新增书籍表、列表/搜索、管理员/馆员维护入口

src/main/java/com/mzh/library/controller/BookCatalogServlet.java

@@ -0,0 +1,98 @@
+package com.mzh.library.controller;
+
+import com.mzh.library.dao.impl.JdbcBookDao;
+import com.mzh.library.entity.AuthenticatedUser;
+import com.mzh.library.entity.Book;
+import com.mzh.library.entity.BookCategory;
+import com.mzh.library.entity.BookSearchCriteria;
+import com.mzh.library.entity.Permission;
+import com.mzh.library.service.BookService;
+import com.mzh.library.service.PermissionPolicy;
+import com.mzh.library.service.ServiceResult;
+import com.mzh.library.service.impl.BookServiceImpl;
+import com.mzh.library.util.SessionAttributes;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.List;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.HttpSession;
+
+public class BookCatalogServlet extends HttpServlet {
+    private static final String CATALOG_JSP = "/WEB-INF/jsp/books/catalog.jsp";
+
+    private BookService bookService;
+    private PermissionPolicy permissionPolicy;
+
+    @Override
+    public void init() {
+        this.bookService = new BookServiceImpl(new JdbcBookDao());
+        this.permissionPolicy = new PermissionPolicy();
+    }
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        BookSearchCriteria criteria = searchCriteria(request);
+        request.setAttribute("criteria", criteria);
+        request.setAttribute("canManageBooks", canManageBooks(request));
+
+        ServiceResult<List<BookCategory>> categoryResult = bookService.listCategories();
+        request.setAttribute("categories", categoryResult.isSuccessful()
+            ? categoryResult.getData()
+            : Collections.emptyList());
+        if (!categoryResult.isSuccessful()) {
+            request.setAttribute("errorMessage", categoryResult.getMessage());
+        }
+
+        ServiceResult<List<Book>> searchResult = bookService.searchBooks(criteria);
+        request.setAttribute("books", searchResult.isSuccessful()
+            ? searchResult.getData()
+            : Collections.emptyList());
+        if (!searchResult.isSuccessful()) {
+            request.setAttribute("errorMessage", searchResult.getMessage());
+            request.setAttribute("errors", searchResult.getErrors());
+        }
+
+        request.getRequestDispatcher(CATALOG_JSP).forward(request, response);
+    }
+
+    private BookSearchCriteria searchCriteria(HttpServletRequest request) {
+        return new BookSearchCriteria(
+            request.getParameter("identifier"),
+            request.getParameter("title"),
+            request.getParameter("author"),
+            optionalLong(request.getParameter("categoryId"))
+        );
+    }
+
+    private Long optionalLong(String value) {
+        String trimmed = trim(value);
+        if (trimmed.isEmpty()) {
+            return null;
+        }
+        try {
+            return Long.valueOf(trimmed);
+        } catch (NumberFormatException ex) {
+            return -1L;
+        }
+    }
+
+    private boolean canManageBooks(HttpServletRequest request) {
+        AuthenticatedUser user = currentUser(request);
+        return user != null && permissionPolicy.allows(user.getRole(), Permission.MANAGE_BOOKS);
+    }
+
+    private AuthenticatedUser currentUser(HttpServletRequest request) {
+        HttpSession session = request.getSession(false);
+        Object value = session == null ? null : session.getAttribute(SessionAttributes.AUTHENTICATED_USER);
+        return value instanceof AuthenticatedUser ? (AuthenticatedUser) value : null;
+    }
+
+    private String trim(String value) {
+        return value == null ? "" : value.trim();
+    }
+}

src/main/java/com/mzh/library/controller/BookManagementServlet.java

@@ -0,0 +1,371 @@
+package com.mzh.library.controller;
+
+import com.mzh.library.dao.impl.JdbcBookDao;
+import com.mzh.library.entity.AuthenticatedUser;
+import com.mzh.library.entity.Book;
+import com.mzh.library.entity.BookCategory;
+import com.mzh.library.entity.BookSearchCriteria;
+import com.mzh.library.entity.BookStatus;
+import com.mzh.library.service.BookService;
+import com.mzh.library.service.ServiceResult;
+import com.mzh.library.service.impl.BookServiceImpl;
+import com.mzh.library.util.SessionAttributes;
+
+import java.io.IOException;
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+
+import javax.servlet.ServletException;
+import javax.servlet.http.HttpServlet;
+import javax.servlet.http.HttpServletRequest;
+import javax.servlet.http.HttpServletResponse;
+import javax.servlet.http.HttpSession;
+
+public class BookManagementServlet extends HttpServlet {
+    private static final String MANAGE_JSP = "/WEB-INF/jsp/books/manage.jsp";
+    private static final String FORM_JSP = "/WEB-INF/jsp/books/form.jsp";
+    private static final String UNAUTHORIZED_JSP = "/WEB-INF/jsp/auth/unauthorized.jsp";
+    private static final String FLASH_SUCCESS = "flashSuccess";
+    private static final String FLASH_ERROR = "flashError";
+
+    private BookService bookService;
+
+    @Override
+    public void init() {
+        this.bookService = new BookServiceImpl(new JdbcBookDao());
+    }
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        String path = request.getServletPath();
+        if ("/books/new".equals(path)) {
+            renderForm(request, response, "Create book", "/books", new Book(), Collections.emptyMap(),
+                Collections.emptyMap(), null);
+            return;
+        }
+        if ("/books/edit".equals(path)) {
+            showEditForm(request, response);
+            return;
+        }
+        if (!"/books".equals(path)) {
+            response.sendError(HttpServletResponse.SC_NOT_FOUND);
+            return;
+        }
+
+        showManagementList(request, response);
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        String path = request.getServletPath();
+        if ("/books".equals(path)) {
+            createBook(request, response);
+            return;
+        }
+        if ("/books/update".equals(path)) {
+            updateBook(request, response);
+            return;
+        }
+        if ("/books/delete".equals(path)) {
+            deleteBook(request, response);
+            return;
+        }
+
+        response.sendError(HttpServletResponse.SC_NOT_FOUND);
+    }
+
+    private void showManagementList(HttpServletRequest request, HttpServletResponse response)
+        throws ServletException, IOException {
+        BookSearchCriteria criteria = searchCriteria(request);
+        request.setAttribute("criteria", criteria);
+        applyFlash(request);
+
+        ServiceResult<List<BookCategory>> categoryResult = bookService.listCategories();
+        request.setAttribute("categories", categoryResult.isSuccessful()
+            ? categoryResult.getData()
+            : Collections.emptyList());
+        if (!categoryResult.isSuccessful()) {
+            request.setAttribute("errorMessage", categoryResult.getMessage());
+        }
+
+        ServiceResult<List<Book>> searchResult = bookService.searchBooks(criteria);
+        request.setAttribute("books", searchResult.isSuccessful()
+            ? searchResult.getData()
+            : Collections.emptyList());
+        if (!searchResult.isSuccessful()) {
+            request.setAttribute("errorMessage", searchResult.getMessage());
+            request.setAttribute("errors", searchResult.getErrors());
+        }
+
+        request.getRequestDispatcher(MANAGE_JSP).forward(request, response);
+    }
+
+    private void showEditForm(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        long id = requiredLong(request.getParameter("id"), -1L);
+        ServiceResult<Optional<Book>> result = bookService.findBook(id);
+        if (!result.isSuccessful() || !result.getData().isPresent()) {
+            flashError(request, result.isSuccessful() ? "Book was not found." : result.getMessage());
+            response.sendRedirect(request.getContextPath() + "/books");
+            return;
+        }
+
+        renderForm(request, response, "Edit book", "/books/update", result.getData().get(),
+            Collections.emptyMap(), Collections.emptyMap(), null);
+    }
+
+    private void createBook(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        BookForm form = readBookForm(request, false);
+        if (!form.getErrors().isEmpty()) {
+            renderForm(request, response, "Create book", "/books", form.getBook(), form.getValues(),
+                form.getErrors(), "Please correct the highlighted book fields.");
+            return;
+        }
+
+        ServiceResult<Long> result = bookService.createBook(currentUser(request), form.getBook());
+        if (!result.isSuccessful()) {
+            handleFormFailure(request, response, "Create book", "/books", form, result);
+            return;
+        }
+
+        flashSuccess(request, result.getMessage());
+        response.sendRedirect(request.getContextPath() + "/books");
+    }
+
+    private void updateBook(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        BookForm form = readBookForm(request, true);
+        if (!form.getErrors().isEmpty()) {
+            renderForm(request, response, "Edit book", "/books/update", form.getBook(), form.getValues(),
+                form.getErrors(), "Please correct the highlighted book fields.");
+            return;
+        }
+
+        ServiceResult<Void> result = bookService.updateBook(currentUser(request), form.getBook());
+        if (!result.isSuccessful()) {
+            handleFormFailure(request, response, "Edit book", "/books/update", form, result);
+            return;
+        }
+
+        flashSuccess(request, result.getMessage());
+        response.sendRedirect(request.getContextPath() + "/books");
+    }
+
+    private void deleteBook(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {
+        long id = requiredLong(request.getParameter("id"), -1L);
+        ServiceResult<Void> result = bookService.deleteBook(currentUser(request), id);
+        if (isPermissionDenied(result)) {
+            forwardDenied(request, response, result.getMessage());
+            return;
+        }
+        if (result.isSuccessful()) {
+            flashSuccess(request, result.getMessage());
+        } else {
+            flashError(request, result.getMessage());
+        }
+        response.sendRedirect(request.getContextPath() + "/books");
+    }
+
+    private void handleFormFailure(HttpServletRequest request, HttpServletResponse response, String title,
+                                   String action, BookForm form, ServiceResult<?> result)
+        throws ServletException, IOException {
+        if (isPermissionDenied(result)) {
+            forwardDenied(request, response, result.getMessage());
+            return;
+        }
+        renderForm(request, response, title, action, form.getBook(), form.getValues(), result.getErrors(),
+            result.getMessage());
+    }
+
+    private void renderForm(HttpServletRequest request, HttpServletResponse response, String title, String action,
+                            Book book, Map<String, String> formValues, Map<String, String> errors, String errorMessage)
+        throws ServletException, IOException {
+        ServiceResult<List<BookCategory>> categoryResult = bookService.listCategories();
+        request.setAttribute("categories", categoryResult.isSuccessful()
+            ? categoryResult.getData()
+            : Collections.emptyList());
+        request.setAttribute("statuses", BookStatus.values());
+        request.setAttribute("formTitle", title);
+        request.setAttribute("formAction", action);
+        request.setAttribute("book", book);
+        request.setAttribute("formValues", formValues);
+        request.setAttribute("errors", errors);
+        if (errorMessage != null && !errorMessage.isEmpty()) {
+            request.setAttribute("errorMessage", errorMessage);
+        } else if (!categoryResult.isSuccessful()) {
+            request.setAttribute("errorMessage", categoryResult.getMessage());
+        }
+        request.getRequestDispatcher(FORM_JSP).forward(request, response);
+    }
+
+    private BookForm readBookForm(HttpServletRequest request, boolean requireId) {
+        Map<String, String> values = formValues(request);
+        Map<String, String> errors = new LinkedHashMap<>();
+        Book book = new Book();
+
+        if (requireId) {
+            book.setId(parseLong(values.get("id"), "id", "Select a valid book.", errors));
+        }
+        book.setIdentifier(values.get("identifier"));
+        book.setTitle(values.get("title"));
+        book.setAuthor(values.get("author"));
+        book.setCategoryId(parseLong(values.get("categoryId"), "categoryId", "Select a category.", errors));
+        book.setTotalCopies(parseInt(values.get("totalCopies"), "totalCopies", "Enter a valid total copy count.", errors));
+        book.setAvailableCopies(parseInt(values.get("availableCopies"), "availableCopies",
+            "Enter a valid available copy count.", errors));
+
+        try {
+            book.setStatus(BookStatus.fromCode(values.get("status")));
+        } catch (IllegalArgumentException ex) {
+            errors.put("status", "Select a status.");
+        }
+
+        return new BookForm(book, values, errors);
+    }
+
+    private Map<String, String> formValues(HttpServletRequest request) {
+        Map<String, String> values = new LinkedHashMap<>();
+        values.put("id", trim(request.getParameter("id")));
+        values.put("identifier", trim(request.getParameter("identifier")));
+        values.put("title", trim(request.getParameter("title")));
+        values.put("author", trim(request.getParameter("author")));
+        values.put("categoryId", trim(request.getParameter("categoryId")));
+        values.put("totalCopies", trim(request.getParameter("totalCopies")));
+        values.put("availableCopies", trim(request.getParameter("availableCopies")));
+        values.put("status", trim(request.getParameter("status")));
+        return values;
+    }
+
+    private BookSearchCriteria searchCriteria(HttpServletRequest request) {
+        return new BookSearchCriteria(
+            request.getParameter("identifier"),
+            request.getParameter("title"),
+            request.getParameter("author"),
+            optionalLong(request.getParameter("categoryId"))
+        );
+    }
+
+    private Long optionalLong(String value) {
+        String trimmed = trim(value);
+        if (trimmed.isEmpty()) {
+            return null;
+        }
+        try {
+            return Long.valueOf(trimmed);
+        } catch (NumberFormatException ex) {
+            return -1L;
+        }
+    }
+
+    private long parseLong(String value, String field, String message, Map<String, String> errors) {
+        String trimmed = trim(value);
+        if (trimmed.isEmpty()) {
+            errors.put(field, message);
+            return 0L;
+        }
+        try {
+            long parsed = Long.parseLong(trimmed);
+            if (parsed <= 0) {
+                errors.put(field, message);
+            }
+            return parsed;
+        } catch (NumberFormatException ex) {
+            errors.put(field, message);
+            return 0L;
+        }
+    }
+
+    private int parseInt(String value, String field, String message, Map<String, String> errors) {
+        String trimmed = trim(value);
+        if (trimmed.isEmpty()) {
+            errors.put(field, message);
+            return -1;
+        }
+        try {
+            return Integer.parseInt(trimmed);
+        } catch (NumberFormatException ex) {
+            errors.put(field, message);
+            return -1;
+        }
+    }
+
+    private long requiredLong(String value, long fallback) {
+        try {
+            long parsed = Long.parseLong(trim(value));
+            return parsed > 0 ? parsed : fallback;
+        } catch (NumberFormatException ex) {
+            return fallback;
+        }
+    }
+
+    private boolean isPermissionDenied(ServiceResult<?> result) {
+        return !result.isSuccessful() && "You do not have permission to manage books.".equals(result.getMessage());
+    }
+
+    private void forwardDenied(HttpServletRequest request, HttpServletResponse response, String message)
+        throws ServletException, IOException {
+        response.setStatus(HttpServletResponse.SC_FORBIDDEN);
+        request.setAttribute("errorMessage", message);
+        request.getRequestDispatcher(UNAUTHORIZED_JSP).forward(request, response);
+    }
+
+    private AuthenticatedUser currentUser(HttpServletRequest request) {
+        HttpSession session = request.getSession(false);
+        Object value = session == null ? null : session.getAttribute(SessionAttributes.AUTHENTICATED_USER);
+        return value instanceof AuthenticatedUser ? (AuthenticatedUser) value : null;
+    }
+
+    private void applyFlash(HttpServletRequest request) {
+        HttpSession session = request.getSession(false);
+        if (session == null) {
+            return;
+        }
+        moveFlash(session, request, FLASH_SUCCESS, "successMessage");
+        moveFlash(session, request, FLASH_ERROR, "errorMessage");
+    }
+
+    private void moveFlash(HttpSession session, HttpServletRequest request, String sessionKey, String requestKey) {
+        Object value = session.getAttribute(sessionKey);
+        if (value != null) {
+            request.setAttribute(requestKey, value);
+            session.removeAttribute(sessionKey);
+        }
+    }
+
+    private void flashSuccess(HttpServletRequest request, String message) {
+        request.getSession().setAttribute(FLASH_SUCCESS, message);
+    }
+
+    private void flashError(HttpServletRequest request, String message) {
+        request.getSession().setAttribute(FLASH_ERROR, message);
+    }
+
+    private String trim(String value) {
+        return value == null ? "" : value.trim();
+    }
+
+    private static final class BookForm {
+        private final Book book;
+        private final Map<String, String> values;
+        private final Map<String, String> errors;
+
+        private BookForm(Book book, Map<String, String> values, Map<String, String> errors) {
+            this.book = book;
+            this.values = values;
+            this.errors = errors;
+        }
+
+        private Book getBook() {
+            return book;
+        }
+
+        private Map<String, String> getValues() {
+            return values;
+        }
+
+        private Map<String, String> getErrors() {
+            return errors;
+        }
+    }
+}

src/main/java/com/mzh/library/dao/BookDao.java

@@ -0,0 +1,24 @@
+package com.mzh.library.dao;
+
+import com.mzh.library.entity.Book;
+import com.mzh.library.entity.BookCategory;
+import com.mzh.library.entity.BookSearchCriteria;
+
+import java.util.List;
+import java.util.Optional;
+
+public interface BookDao {
+    List<BookCategory> findAllCategories();
+
+    List<Book> search(BookSearchCriteria criteria);
+
+    Optional<Book> findById(long id);
+
+    Optional<Book> findByIdentifier(String identifier);
+
+    long create(Book book);
+
+    boolean update(Book book);
+
+    boolean delete(long id);
+}

src/main/java/com/mzh/library/dao/impl/JdbcBookDao.java

@@ -0,0 +1,224 @@
+package com.mzh.library.dao.impl;
+
+import com.mzh.library.dao.BookDao;
+import com.mzh.library.entity.Book;
+import com.mzh.library.entity.BookCategory;
+import com.mzh.library.entity.BookSearchCriteria;
+import com.mzh.library.entity.BookStatus;
+import com.mzh.library.exception.DaoException;
+import com.mzh.library.util.JdbcUtil;
+
+import java.sql.Connection;
+import java.sql.PreparedStatement;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.sql.Statement;
+import java.sql.Timestamp;
+import java.time.LocalDateTime;
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Optional;
+
+public class JdbcBookDao implements BookDao {
+    private static final String BOOK_COLUMNS = ""
+        + "b.id, b.book_identifier, b.title, b.author, b.category_id, c.name AS category_name, "
+        + "b.total_copies, b.available_copies, b.status, b.created_at, b.updated_at ";
+
+    private static final String BOOK_FROM = ""
+        + "FROM books b "
+        + "JOIN book_categories c ON c.id = b.category_id ";
+
+    private static final String FIND_ALL_CATEGORIES = ""
+        + "SELECT id, name, description "
+        + "FROM book_categories "
+        + "ORDER BY name";
+
+    private static final String FIND_BY_ID = "SELECT " + BOOK_COLUMNS + BOOK_FROM + "WHERE b.id = ?";
+
+    private static final String FIND_BY_IDENTIFIER = "SELECT " + BOOK_COLUMNS + BOOK_FROM
+        + "WHERE b.book_identifier = ?";
+
+    private static final String CREATE = ""
+        + "INSERT INTO books "
+        + "(book_identifier, title, author, category_id, total_copies, available_copies, status) "
+        + "VALUES (?, ?, ?, ?, ?, ?, ?)";
+
+    private static final String UPDATE = ""
+        + "UPDATE books "
+        + "SET book_identifier = ?, title = ?, author = ?, category_id = ?, total_copies = ?, "
+        + "available_copies = ?, status = ? "
+        + "WHERE id = ?";
+
+    private static final String DELETE = "DELETE FROM books WHERE id = ?";
+
+    @Override
+    public List<BookCategory> findAllCategories() {
+        try (Connection connection = JdbcUtil.getConnection();
+             PreparedStatement statement = connection.prepareStatement(FIND_ALL_CATEGORIES);
+             ResultSet resultSet = statement.executeQuery()) {
+            List<BookCategory> categories = new ArrayList<>();
+            while (resultSet.next()) {
+                categories.add(mapCategory(resultSet));
+            }
+            return categories;
+        } catch (SQLException ex) {
+            throw new DaoException("Unable to load book categories", ex);
+        }
+    }
+
+    @Override
+    public List<Book> search(BookSearchCriteria criteria) {
+        List<Object> parameters = new ArrayList<>();
+        StringBuilder sql = new StringBuilder("SELECT ")
+            .append(BOOK_COLUMNS)
+            .append(BOOK_FROM)
+            .append("WHERE 1 = 1 ");
+
+        appendLike(sql, parameters, "b.book_identifier", criteria.getIdentifier());
+        appendLike(sql, parameters, "b.title", criteria.getTitle());
+        appendLike(sql, parameters, "b.author", criteria.getAuthor());
+        if (criteria.getCategoryId() != null) {
+            sql.append("AND b.category_id = ? ");
+            parameters.add(criteria.getCategoryId());
+        }
+        sql.append("ORDER BY b.title, b.author, b.book_identifier");
+
+        try (Connection connection = JdbcUtil.getConnection();
+             PreparedStatement statement = connection.prepareStatement(sql.toString())) {
+            bind(statement, parameters);
+            try (ResultSet resultSet = statement.executeQuery()) {
+                List<Book> books = new ArrayList<>();
+                while (resultSet.next()) {
+                    books.add(mapBook(resultSet));
+                }
+                return books;
+            }
+        } catch (SQLException | IllegalArgumentException ex) {
+            throw new DaoException("Unable to search books", ex);
+        }
+    }
+
+    @Override
+    public Optional<Book> findById(long id) {
+        try (Connection connection = JdbcUtil.getConnection();
+             PreparedStatement statement = connection.prepareStatement(FIND_BY_ID)) {
+            statement.setLong(1, id);
+            try (ResultSet resultSet = statement.executeQuery()) {
+                return resultSet.next() ? Optional.of(mapBook(resultSet)) : Optional.empty();
+            }
+        } catch (SQLException | IllegalArgumentException ex) {
+            throw new DaoException("Unable to load book by id", ex);
+        }
+    }
+
+    @Override
+    public Optional<Book> findByIdentifier(String identifier) {
+        try (Connection connection = JdbcUtil.getConnection();
+             PreparedStatement statement = connection.prepareStatement(FIND_BY_IDENTIFIER)) {
+            statement.setString(1, identifier);
+            try (ResultSet resultSet = statement.executeQuery()) {
+                return resultSet.next() ? Optional.of(mapBook(resultSet)) : Optional.empty();
+            }
+        } catch (SQLException | IllegalArgumentException ex) {
+            throw new DaoException("Unable to load book by identifier", ex);
+        }
+    }
+
+    @Override
+    public long create(Book book) {
+        try (Connection connection = JdbcUtil.getConnection();
+             PreparedStatement statement = connection.prepareStatement(CREATE, Statement.RETURN_GENERATED_KEYS)) {
+            bindBook(statement, book);
+            statement.executeUpdate();
+
+            try (ResultSet generatedKeys = statement.getGeneratedKeys()) {
+                if (generatedKeys.next()) {
+                    return generatedKeys.getLong(1);
+                }
+            }
+            throw new DaoException("Unable to read generated book id", null);
+        } catch (SQLException ex) {
+            throw new DaoException("Unable to create book", ex);
+        }
+    }
+
+    @Override
+    public boolean update(Book book) {
+        try (Connection connection = JdbcUtil.getConnection();
+             PreparedStatement statement = connection.prepareStatement(UPDATE)) {
+            bindBook(statement, book);
+            statement.setLong(8, book.getId());
+            return statement.executeUpdate() == 1;
+        } catch (SQLException ex) {
+            throw new DaoException("Unable to update book", ex);
+        }
+    }
+
+    @Override
+    public boolean delete(long id) {
+        try (Connection connection = JdbcUtil.getConnection();
+             PreparedStatement statement = connection.prepareStatement(DELETE)) {
+            statement.setLong(1, id);
+            return statement.executeUpdate() == 1;
+        } catch (SQLException ex) {
+            throw new DaoException("Unable to delete book", ex);
+        }
+    }
+
+    private void appendLike(StringBuilder sql, List<Object> parameters, String column, String value) {
+        if (value == null || value.trim().isEmpty()) {
+            return;
+        }
+        sql.append("AND ").append(column).append(" LIKE ? ");
+        parameters.add("%" + value.trim() + "%");
+    }
+
+    private void bind(PreparedStatement statement, List<Object> parameters) throws SQLException {
+        for (int i = 0; i < parameters.size(); i++) {
+            Object value = parameters.get(i);
+            if (value instanceof Long) {
+                statement.setLong(i + 1, (Long) value);
+            } else {
+                statement.setString(i + 1, value.toString());
+            }
+        }
+    }
+
+    private void bindBook(PreparedStatement statement, Book book) throws SQLException {
+        statement.setString(1, book.getIdentifier());
+        statement.setString(2, book.getTitle());
+        statement.setString(3, book.getAuthor());
+        statement.setLong(4, book.getCategoryId());
+        statement.setInt(5, book.getTotalCopies());
+        statement.setInt(6, book.getAvailableCopies());
+        statement.setString(7, book.getStatus().getCode());
+    }
+
+    private Book mapBook(ResultSet resultSet) throws SQLException {
+        Book book = new Book();
+        book.setId(resultSet.getLong("id"));
+        book.setIdentifier(resultSet.getString("book_identifier"));
+        book.setTitle(resultSet.getString("title"));
+        book.setAuthor(resultSet.getString("author"));
+        book.setCategoryId(resultSet.getLong("category_id"));
+        book.setCategoryName(resultSet.getString("category_name"));
+        book.setTotalCopies(resultSet.getInt("total_copies"));
+        book.setAvailableCopies(resultSet.getInt("available_copies"));
+        book.setStatus(BookStatus.fromCode(resultSet.getString("status")));
+        book.setCreatedAt(toLocalDateTime(resultSet.getTimestamp("created_at")));
+        book.setUpdatedAt(toLocalDateTime(resultSet.getTimestamp("updated_at")));
+        return book;
+    }
+
+    private BookCategory mapCategory(ResultSet resultSet) throws SQLException {
+        BookCategory category = new BookCategory();
+        category.setId(resultSet.getLong("id"));
+        category.setName(resultSet.getString("name"));
+        category.setDescription(resultSet.getString("description"));
+        return category;
+    }
+
+    private LocalDateTime toLocalDateTime(Timestamp timestamp) {
+        return timestamp == null ? null : timestamp.toLocalDateTime();
+    }
+}

src/main/java/com/mzh/library/entity/Book.java

@@ -0,0 +1,105 @@
+package com.mzh.library.entity;
+
+import java.time.LocalDateTime;
+
+public class Book {
+    private long id;
+    private String identifier;
+    private String title;
+    private String author;
+    private long categoryId;
+    private String categoryName;
+    private int totalCopies;
+    private int availableCopies;
+    private BookStatus status;
+    private LocalDateTime createdAt;
+    private LocalDateTime updatedAt;
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getIdentifier() {
+        return identifier;
+    }
+
+    public void setIdentifier(String identifier) {
+        this.identifier = identifier;
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    public String getAuthor() {
+        return author;
+    }
+
+    public void setAuthor(String author) {
+        this.author = author;
+    }
+
+    public long getCategoryId() {
+        return categoryId;
+    }
+
+    public void setCategoryId(long categoryId) {
+        this.categoryId = categoryId;
+    }
+
+    public String getCategoryName() {
+        return categoryName;
+    }
+
+    public void setCategoryName(String categoryName) {
+        this.categoryName = categoryName;
+    }
+
+    public int getTotalCopies() {
+        return totalCopies;
+    }
+
+    public void setTotalCopies(int totalCopies) {
+        this.totalCopies = totalCopies;
+    }
+
+    public int getAvailableCopies() {
+        return availableCopies;
+    }
+
+    public void setAvailableCopies(int availableCopies) {
+        this.availableCopies = availableCopies;
+    }
+
+    public BookStatus getStatus() {
+        return status;
+    }
+
+    public void setStatus(BookStatus status) {
+        this.status = status;
+    }
+
+    public LocalDateTime getCreatedAt() {
+        return createdAt;
+    }
+
+    public void setCreatedAt(LocalDateTime createdAt) {
+        this.createdAt = createdAt;
+    }
+
+    public LocalDateTime getUpdatedAt() {
+        return updatedAt;
+    }
+
+    public void setUpdatedAt(LocalDateTime updatedAt) {
+        this.updatedAt = updatedAt;
+    }
+}

src/main/java/com/mzh/library/entity/BookCategory.java

@@ -0,0 +1,31 @@
+package com.mzh.library.entity;
+
+public class BookCategory {
+    private long id;
+    private String name;
+    private String description;
+
+    public long getId() {
+        return id;
+    }
+
+    public void setId(long id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public void setDescription(String description) {
+        this.description = description;
+    }
+}

src/main/java/com/mzh/library/entity/BookSearchCriteria.java

@@ -0,0 +1,54 @@
+package com.mzh.library.entity;
+
+public class BookSearchCriteria {
+    private String identifier;
+    private String title;
+    private String author;
+    private Long categoryId;
+
+    public BookSearchCriteria() {
+    }
+
+    public BookSearchCriteria(String identifier, String title, String author, Long categoryId) {
+        this.identifier = trim(identifier);
+        this.title = trim(title);
+        this.author = trim(author);
+        this.categoryId = categoryId;
+    }
+
+    public String getIdentifier() {
+        return identifier;
+    }
+
+    public void setIdentifier(String identifier) {
+        this.identifier = trim(identifier);
+    }
+
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = trim(title);
+    }
+
+    public String getAuthor() {
+        return author;
+    }
+
+    public void setAuthor(String author) {
+        this.author = trim(author);
+    }
+
+    public Long getCategoryId() {
+        return categoryId;
+    }
+
+    public void setCategoryId(Long categoryId) {
+        this.categoryId = categoryId;
+    }
+
+    private String trim(String value) {
+        return value == null ? "" : value.trim();
+    }
+}

src/main/java/com/mzh/library/entity/BookStatus.java

@@ -0,0 +1,40 @@
+package com.mzh.library.entity;
+
+import java.util.Locale;
+
+public enum BookStatus {
+    AVAILABLE("available", "Available"),
+    UNAVAILABLE("unavailable", "Unavailable"),
+    ARCHIVED("archived", "Archived");
+
+    private final String code;
+    private final String displayName;
+
+    BookStatus(String code, String displayName) {
+        this.code = code;
+        this.displayName = displayName;
+    }
+
+    public String getCode() {
+        return code;
+    }
+
+    public String getDisplayName() {
+        return displayName;
+    }
+
+    public static BookStatus fromCode(String code) {
+        if (code == null || code.trim().isEmpty()) {
+            throw new IllegalArgumentException("Book status is required");
+        }
+
+        String normalized = code.trim().toLowerCase(Locale.ROOT);
+        for (BookStatus status : values()) {
+            if (status.code.equals(normalized)) {
+                return status;
+            }
+        }
+
+        throw new IllegalArgumentException("Unsupported book status: " + code);
+    }
+}

src/main/java/com/mzh/library/exception/DaoException.java

@@ -1,6 +1,8 @@
 package com.mzh.library.exception;
 
 public class DaoException extends RuntimeException {
+    private static final long serialVersionUID = 1L;
+
     public DaoException(String message, Throwable cause) {
         super(message, cause);
     }

src/main/java/com/mzh/library/filter/AuthorizationFilter.java

@@ -25,6 +25,8 @@ public class AuthorizationFilter implements Filter {
     private static final Logger LOGGER = Logger.getLogger(AuthorizationFilter.class.getName());
     private static final String UNAUTHORIZED_JSP = "/WEB-INF/jsp/auth/unauthorized.jsp";
     private static final List<PathRule> RULES = Arrays.asList(
+        new PathRule("/books", Permission.MANAGE_BOOKS),
+        new PathRule("/catalog", Permission.VIEW_CATALOG),
         new PathRule("/admin", Permission.MANAGE_USERS),
         new PathRule("/librarian", Permission.MANAGE_BORROWING),
         new PathRule("/reader", Permission.VIEW_CATALOG)

src/main/java/com/mzh/library/service/BookService.java

@@ -0,0 +1,23 @@
+package com.mzh.library.service;
+
+import com.mzh.library.entity.AuthenticatedUser;
+import com.mzh.library.entity.Book;
+import com.mzh.library.entity.BookCategory;
+import com.mzh.library.entity.BookSearchCriteria;
+
+import java.util.List;
+import java.util.Optional;
+
+public interface BookService {
+    ServiceResult<List<BookCategory>> listCategories();
+
+    ServiceResult<List<Book>> searchBooks(BookSearchCriteria criteria);
+
+    ServiceResult<Optional<Book>> findBook(long id);
+
+    ServiceResult<Long> createBook(AuthenticatedUser actor, Book book);
+
+    ServiceResult<Void> updateBook(AuthenticatedUser actor, Book book);
+
+    ServiceResult<Void> deleteBook(AuthenticatedUser actor, long id);
+}

src/main/java/com/mzh/library/service/ServiceResult.java

@@ -0,0 +1,55 @@
+package com.mzh.library.service;
+
+import java.util.Collections;
+import java.util.LinkedHashMap;
+import java.util.Map;
+
+public class ServiceResult<T> {
+    private final boolean successful;
+    private final T data;
+    private final String message;
+    private final Map<String, String> errors;
+
+    private ServiceResult(boolean successful, T data, String message, Map<String, String> errors) {
+        this.successful = successful;
+        this.data = data;
+        this.message = message;
+        this.errors = Collections.unmodifiableMap(new LinkedHashMap<>(errors));
+    }
+
+    public static <T> ServiceResult<T> success(T data) {
+        return new ServiceResult<>(true, data, null, Collections.emptyMap());
+    }
+
+    public static <T> ServiceResult<T> success(T data, String message) {
+        return new ServiceResult<>(true, data, message, Collections.emptyMap());
+    }
+
+    public static <T> ServiceResult<T> failure(String message) {
+        return new ServiceResult<>(false, null, message, Collections.emptyMap());
+    }
+
+    public static <T> ServiceResult<T> validationFailure(String message, Map<String, String> errors) {
+        return new ServiceResult<>(false, null, message, errors);
+    }
+
+    public boolean isSuccessful() {
+        return successful;
+    }
+
+    public T getData() {
+        return data;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public Map<String, String> getErrors() {
+        return errors;
+    }
+
+    public boolean hasErrors() {
+        return !errors.isEmpty();
+    }
+}

src/main/java/com/mzh/library/service/impl/BookServiceImpl.java

@@ -0,0 +1,218 @@
+package com.mzh.library.service.impl;
+
+import com.mzh.library.dao.BookDao;
+import com.mzh.library.entity.AuthenticatedUser;
+import com.mzh.library.entity.Book;
+import com.mzh.library.entity.BookCategory;
+import com.mzh.library.entity.BookSearchCriteria;
+import com.mzh.library.entity.Permission;
+import com.mzh.library.exception.DaoException;
+import com.mzh.library.service.BookService;
+import com.mzh.library.service.PermissionPolicy;
+import com.mzh.library.service.ServiceResult;
+
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public class BookServiceImpl implements BookService {
+    private static final Logger LOGGER = Logger.getLogger(BookServiceImpl.class.getName());
+    private static final String UNAVAILABLE_MESSAGE =
+        "Book service is temporarily unavailable. Please try again later.";
+    private static final String VALIDATION_MESSAGE = "Please correct the highlighted book fields.";
+    private static final String DENIED_MESSAGE = "You do not have permission to manage books.";
+
+    private final BookDao bookDao;
+    private final PermissionPolicy permissionPolicy;
+
+    public BookServiceImpl(BookDao bookDao) {
+        this(bookDao, new PermissionPolicy());
+    }
+
+    public BookServiceImpl(BookDao bookDao, PermissionPolicy permissionPolicy) {
+        this.bookDao = bookDao;
+        this.permissionPolicy = permissionPolicy;
+    }
+
+    @Override
+    public ServiceResult<List<BookCategory>> listCategories() {
+        try {
+            return ServiceResult.success(bookDao.findAllCategories());
+        } catch (DaoException ex) {
+            LOGGER.log(Level.SEVERE, "Unable to list book categories", ex);
+            return ServiceResult.failure(UNAVAILABLE_MESSAGE);
+        }
+    }
+
+    @Override
+    public ServiceResult<List<Book>> searchBooks(BookSearchCriteria criteria) {
+        BookSearchCriteria normalized = criteria == null ? new BookSearchCriteria() : criteria;
+        if (normalized.getCategoryId() != null && normalized.getCategoryId() <= 0) {
+            Map<String, String> errors = new LinkedHashMap<>();
+            errors.put("categoryId", "Select a valid category.");
+            return ServiceResult.validationFailure("Please correct the catalog search filters.", errors);
+        }
+
+        try {
+            return ServiceResult.success(bookDao.search(normalized));
+        } catch (DaoException ex) {
+            LOGGER.log(Level.SEVERE, "Unable to search books", ex);
+            return ServiceResult.failure(UNAVAILABLE_MESSAGE);
+        }
+    }
+
+    @Override
+    public ServiceResult<Optional<Book>> findBook(long id) {
+        if (id <= 0) {
+            return ServiceResult.failure("Select a valid book.");
+        }
+
+        try {
+            return ServiceResult.success(bookDao.findById(id));
+        } catch (DaoException ex) {
+            LOGGER.log(Level.SEVERE, "Unable to load book id=" + id, ex);
+            return ServiceResult.failure(UNAVAILABLE_MESSAGE);
+        }
+    }
+
+    @Override
+    public ServiceResult<Long> createBook(AuthenticatedUser actor, Book book) {
+        if (!canManageBooks(actor)) {
+            return ServiceResult.failure(DENIED_MESSAGE);
+        }
+
+        normalize(book);
+        Map<String, String> errors = validate(book, false);
+        if (!errors.isEmpty()) {
+            return ServiceResult.validationFailure(VALIDATION_MESSAGE, errors);
+        }
+
+        try {
+            if (bookDao.findByIdentifier(book.getIdentifier()).isPresent()) {
+                errors.put("identifier", "Book identifier is already in use.");
+                return ServiceResult.validationFailure(VALIDATION_MESSAGE, errors);
+            }
+
+            long id = bookDao.create(book);
+            LOGGER.info("Created book id=" + id + " actorId=" + actor.getId());
+            return ServiceResult.success(id, "Book created.");
+        } catch (DaoException ex) {
+            LOGGER.log(Level.SEVERE, "Unable to create book actorId=" + actor.getId(), ex);
+            return ServiceResult.failure(UNAVAILABLE_MESSAGE);
+        }
+    }
+
+    @Override
+    public ServiceResult<Void> updateBook(AuthenticatedUser actor, Book book) {
+        if (!canManageBooks(actor)) {
+            return ServiceResult.failure(DENIED_MESSAGE);
+        }
+
+        normalize(book);
+        Map<String, String> errors = validate(book, true);
+        if (!errors.isEmpty()) {
+            return ServiceResult.validationFailure(VALIDATION_MESSAGE, errors);
+        }
+
+        try {
+            Optional<Book> existingWithIdentifier = bookDao.findByIdentifier(book.getIdentifier());
+            if (existingWithIdentifier.isPresent() && existingWithIdentifier.get().getId() != book.getId()) {
+                errors.put("identifier", "Book identifier is already in use.");
+                return ServiceResult.validationFailure(VALIDATION_MESSAGE, errors);
+            }
+
+            if (!bookDao.update(book)) {
+                return ServiceResult.failure("Book was not found.");
+            }
+
+            LOGGER.info("Updated book id=" + book.getId() + " actorId=" + actor.getId());
+            return ServiceResult.success(null, "Book updated.");
+        } catch (DaoException ex) {
+            LOGGER.log(Level.SEVERE, "Unable to update book id=" + book.getId() + " actorId=" + actor.getId(), ex);
+            return ServiceResult.failure(UNAVAILABLE_MESSAGE);
+        }
+    }
+
+    @Override
+    public ServiceResult<Void> deleteBook(AuthenticatedUser actor, long id) {
+        if (!canManageBooks(actor)) {
+            return ServiceResult.failure(DENIED_MESSAGE);
+        }
+        if (id <= 0) {
+            return ServiceResult.failure("Select a valid book.");
+        }
+
+        try {
+            if (!bookDao.delete(id)) {
+                return ServiceResult.failure("Book was not found.");
+            }
+
+            LOGGER.info("Deleted book id=" + id + " actorId=" + actor.getId());
+            return ServiceResult.success(null, "Book deleted.");
+        } catch (DaoException ex) {
+            LOGGER.log(Level.SEVERE, "Unable to delete book id=" + id + " actorId=" + actor.getId(), ex);
+            return ServiceResult.failure(UNAVAILABLE_MESSAGE);
+        }
+    }
+
+    private boolean canManageBooks(AuthenticatedUser actor) {
+        return actor != null && permissionPolicy.allows(actor.getRole(), Permission.MANAGE_BOOKS);
+    }
+
+    private void normalize(Book book) {
+        if (book == null) {
+            return;
+        }
+        book.setIdentifier(trim(book.getIdentifier()));
+        book.setTitle(trim(book.getTitle()));
+        book.setAuthor(trim(book.getAuthor()));
+    }
+
+    private Map<String, String> validate(Book book, boolean requireId) {
+        Map<String, String> errors = new LinkedHashMap<>();
+        if (book == null) {
+            errors.put("book", "Book details are required.");
+            return errors;
+        }
+
+        if (requireId && book.getId() <= 0) {
+            errors.put("id", "Select a valid book.");
+        }
+        requireLength(errors, "identifier", book.getIdentifier(), "Book identifier", 64);
+        requireLength(errors, "title", book.getTitle(), "Title", 200);
+        requireLength(errors, "author", book.getAuthor(), "Author", 120);
+        if (book.getCategoryId() <= 0) {
+            errors.put("categoryId", "Select a category.");
+        }
+        if (book.getTotalCopies() < 0) {
+            errors.put("totalCopies", "Total copies cannot be negative.");
+        }
+        if (book.getAvailableCopies() < 0) {
+            errors.put("availableCopies", "Available copies cannot be negative.");
+        }
+        if (book.getAvailableCopies() > book.getTotalCopies()) {
+            errors.put("availableCopies", "Available copies cannot exceed total copies.");
+        }
+        if (book.getStatus() == null) {
+            errors.put("status", "Select a status.");
+        }
+        return errors;
+    }
+
+    private void requireLength(Map<String, String> errors, String field, String value, String label, int maxLength) {
+        if (value == null || value.isEmpty()) {
+            errors.put(field, label + " is required.");
+            return;
+        }
+        if (value.length() > maxLength) {
+            errors.put(field, label + " must be " + maxLength + " characters or fewer.");
+        }
+    }
+
+    private String trim(String value) {
+        return value == null ? "" : value.trim();
+    }
+}

src/main/resources/db/schema.sql

@@ -57,6 +57,41 @@ CREATE TABLE IF NOT EXISTS system_logs (
   KEY idx_system_logs_created_at (created_at)
 ) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
 
+CREATE TABLE IF NOT EXISTS book_categories (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  name VARCHAR(96) NOT NULL,
+  description VARCHAR(255) NULL,
+  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  UNIQUE KEY uk_book_categories_name (name)
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
+CREATE TABLE IF NOT EXISTS books (
+  id BIGINT PRIMARY KEY AUTO_INCREMENT,
+  book_identifier VARCHAR(64) NOT NULL,
+  title VARCHAR(200) NOT NULL,
+  author VARCHAR(120) NOT NULL,
+  category_id BIGINT NOT NULL,
+  total_copies INT NOT NULL DEFAULT 0,
+  available_copies INT NOT NULL DEFAULT 0,
+  status VARCHAR(32) NOT NULL DEFAULT 'available',
+  created_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP,
+  updated_at TIMESTAMP NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
+  UNIQUE KEY uk_books_identifier (book_identifier),
+  KEY idx_books_title (title),
+  KEY idx_books_author (author),
+  KEY idx_books_category_id (category_id),
+  KEY idx_books_status (status),
+  CONSTRAINT fk_books_category
+    FOREIGN KEY (category_id) REFERENCES book_categories (id),
+  CONSTRAINT chk_books_total_copies
+    CHECK (total_copies >= 0),
+  CONSTRAINT chk_books_available_copies
+    CHECK (available_copies >= 0 AND available_copies <= total_copies),
+  CONSTRAINT chk_books_status
+    CHECK (status IN ('available', 'unavailable', 'archived'))
+) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci;
+
 INSERT INTO roles (code, name, description) VALUES
   ('administrator', 'Administrator', 'Full system administration role'),
   ('librarian', 'Librarian', 'Library operation and borrowing management role'),
@@ -101,3 +136,28 @@ INSERT IGNORE INTO users (username, password_hash, display_name, role_code, acti
   ('admin', 'pbkdf2_sha256$60000$bXpoLWFkbWluLWRlbW8tc2FsdA==$RwBCvhf3Wsc0jemnHlir4mdNZF4ZhHjrfHx/b1Bera0=', 'System Administrator', 'administrator', 1),
   ('librarian', 'pbkdf2_sha256$60000$bXpoLWxpYnJhcmlhbi1kZW1vLXNhbHQ=$StIdJGDRIiF4aCr+qKuwvob5sL3+6j1caF2sQNqFi78=', 'Library Staff', 'librarian', 1),
   ('reader', 'pbkdf2_sha256$60000$bXpoLXJlYWRlci1kZW1vLXNhbHQ=$iaiZPGhaIQ+2R2o9UQRj6wsrmYSJ4efqS3jCzM/XU7g=', 'Demo Reader', 'reader', 1);
+
+INSERT INTO book_categories (name, description) VALUES
+  ('Computer Science', 'Programming, software engineering, and systems books'),
+  ('Literature', 'Classic and modern literature'),
+  ('History', 'World and regional history'),
+  ('Science', 'Natural science and popular science')
+ON DUPLICATE KEY UPDATE
+  description = VALUES(description);
+
+INSERT INTO books (book_identifier, title, author, category_id, total_copies, available_copies, status) VALUES
+  ('BK-0001', 'Effective Java', 'Joshua Bloch',
+    (SELECT id FROM book_categories WHERE name = 'Computer Science'), 5, 4, 'available'),
+  ('BK-0002', 'Clean Code', 'Robert C. Martin',
+    (SELECT id FROM book_categories WHERE name = 'Computer Science'), 4, 2, 'available'),
+  ('BK-0003', 'Pride and Prejudice', 'Jane Austen',
+    (SELECT id FROM book_categories WHERE name = 'Literature'), 3, 3, 'available'),
+  ('BK-0004', 'A Brief History of Time', 'Stephen Hawking',
+    (SELECT id FROM book_categories WHERE name = 'Science'), 2, 1, 'available')
+ON DUPLICATE KEY UPDATE
+  title = VALUES(title),
+  author = VALUES(author),
+  category_id = VALUES(category_id),
+  total_copies = VALUES(total_copies),
+  available_copies = VALUES(available_copies),
+  status = VALUES(status);

src/main/webapp/WEB-INF/jsp/books/catalog.jsp

@@ -0,0 +1,109 @@
+<%@ page contentType="text/html;charset=UTF-8" pageEncoding="UTF-8" %>
+<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
+<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
+<!doctype html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <title>Catalog - MZH Library</title>
+    <link rel="stylesheet" href="${pageContext.request.contextPath}/static/css/app.css">
+</head>
+<body>
+<%@ include file="/WEB-INF/jsp/common/header.jspf" %>
+<main class="page-shell">
+    <section class="dashboard-hero catalog-hero" aria-labelledby="catalog-title">
+        <p class="eyebrow">Catalog</p>
+        <h1 id="catalog-title">Book catalog</h1>
+        <p>Search the library collection by identifier, title, author, or category.</p>
+    </section>
+
+    <c:if test="${not empty errorMessage}">
+        <div class="message message-error" role="alert">
+            <c:out value="${errorMessage}" />
+        </div>
+    </c:if>
+
+    <section class="toolbar-panel" aria-label="Catalog search">
+        <form class="search-form" action="${pageContext.request.contextPath}/catalog" method="get">
+            <div class="search-field">
+                <label for="identifier">Book ID</label>
+                <input id="identifier" name="identifier" type="text" value="${fn:escapeXml(criteria.identifier)}">
+            </div>
+
+            <div class="search-field">
+                <label for="title">Title</label>
+                <input id="title" name="title" type="text" value="${fn:escapeXml(criteria.title)}">
+            </div>
+
+            <div class="search-field">
+                <label for="author">Author</label>
+                <input id="author" name="author" type="text" value="${fn:escapeXml(criteria.author)}">
+            </div>
+
+            <div class="search-field">
+                <label for="categoryId">Category</label>
+                <select id="categoryId" name="categoryId">
+                    <option value="">All categories</option>
+                    <c:forEach var="category" items="${categories}">
+                        <option value="${category.id}" <c:if test="${criteria.categoryId == category.id}">selected</c:if>>
+                            <c:out value="${category.name}" />
+                        </option>
+                    </c:forEach>
+                </select>
+                <c:if test="${not empty errors.categoryId}">
+                    <span class="field-error"><c:out value="${errors.categoryId}" /></span>
+                </c:if>
+            </div>
+
+            <button class="button button-primary" type="submit">Search</button>
+            <a class="button button-secondary" href="${pageContext.request.contextPath}/catalog">Clear</a>
+            <c:if test="${canManageBooks}">
+                <a class="button button-secondary" href="${pageContext.request.contextPath}/books">Manage books</a>
+            </c:if>
+        </form>
+    </section>
+
+    <section class="table-panel" aria-labelledby="catalog-results-title">
+        <h2 id="catalog-results-title">Results</h2>
+        <c:choose>
+            <c:when test="${empty books}">
+                <p class="empty-state">No books match the current filters.</p>
+            </c:when>
+            <c:otherwise>
+                <div class="table-scroll">
+                    <table class="data-table">
+                        <thead>
+                        <tr>
+                            <th scope="col">Book ID</th>
+                            <th scope="col">Title</th>
+                            <th scope="col">Author</th>
+                            <th scope="col">Category</th>
+                            <th scope="col">Copies</th>
+                            <th scope="col">Status</th>
+                        </tr>
+                        </thead>
+                        <tbody>
+                        <c:forEach var="book" items="${books}">
+                            <tr>
+                                <td><c:out value="${book.identifier}" /></td>
+                                <td><c:out value="${book.title}" /></td>
+                                <td><c:out value="${book.author}" /></td>
+                                <td><c:out value="${book.categoryName}" /></td>
+                                <td><c:out value="${book.availableCopies}" /> / <c:out value="${book.totalCopies}" /></td>
+                                <td>
+                                    <span class="status-pill status-${book.status.code}">
+                                        <c:out value="${book.status.displayName}" />
+                                    </span>
+                                </td>
+                            </tr>
+                        </c:forEach>
+                        </tbody>
+                    </table>
+                </div>
+            </c:otherwise>
+        </c:choose>
+    </section>
+</main>
+</body>
+</html>

src/main/webapp/WEB-INF/jsp/books/form.jsp

@@ -0,0 +1,119 @@
+<%@ page contentType="text/html;charset=UTF-8" pageEncoding="UTF-8" %>
+<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
+<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
+<!doctype html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <title><c:out value="${formTitle}" /> - MZH Library</title>
+    <link rel="stylesheet" href="${pageContext.request.contextPath}/static/css/app.css">
+</head>
+<body>
+<%@ include file="/WEB-INF/jsp/common/header.jspf" %>
+<main class="page-shell">
+    <section class="form-panel" aria-labelledby="book-form-title">
+        <p class="eyebrow">Book Management</p>
+        <h1 id="book-form-title"><c:out value="${formTitle}" /></h1>
+
+        <c:if test="${not empty errorMessage}">
+            <div class="message message-error" role="alert">
+                <c:out value="${errorMessage}" />
+            </div>
+        </c:if>
+
+        <c:set var="hasFormValues" value="${not empty formValues}" />
+        <c:set var="identifierValue" value="${hasFormValues ? formValues.identifier : book.identifier}" />
+        <c:set var="titleValue" value="${hasFormValues ? formValues.title : book.title}" />
+        <c:set var="authorValue" value="${hasFormValues ? formValues.author : book.author}" />
+        <c:set var="categoryValue" value="${book.categoryId}" />
+        <c:set var="totalCopiesValue" value="${hasFormValues ? formValues.totalCopies : book.totalCopies}" />
+        <c:set var="availableCopiesValue" value="${hasFormValues ? formValues.availableCopies : book.availableCopies}" />
+        <c:set var="statusValue" value="${hasFormValues ? formValues.status : book.status.code}" />
+
+        <form class="book-form" action="${pageContext.request.contextPath}${formAction}" method="post" novalidate>
+            <c:if test="${book.id > 0}">
+                <input type="hidden" name="id" value="${book.id}">
+            </c:if>
+
+            <div class="form-grid">
+                <div class="form-field">
+                    <label for="identifier">Book ID</label>
+                    <input id="identifier" name="identifier" type="text" value="${fn:escapeXml(identifierValue)}" required>
+                    <c:if test="${not empty errors.identifier}">
+                        <span class="field-error"><c:out value="${errors.identifier}" /></span>
+                    </c:if>
+                </div>
+
+                <div class="form-field">
+                    <label for="title">Title</label>
+                    <input id="title" name="title" type="text" value="${fn:escapeXml(titleValue)}" required>
+                    <c:if test="${not empty errors.title}">
+                        <span class="field-error"><c:out value="${errors.title}" /></span>
+                    </c:if>
+                </div>
+
+                <div class="form-field">
+                    <label for="author">Author</label>
+                    <input id="author" name="author" type="text" value="${fn:escapeXml(authorValue)}" required>
+                    <c:if test="${not empty errors.author}">
+                        <span class="field-error"><c:out value="${errors.author}" /></span>
+                    </c:if>
+                </div>
+
+                <div class="form-field">
+                    <label for="categoryId">Category</label>
+                    <select id="categoryId" name="categoryId" required>
+                        <option value="">Select category</option>
+                        <c:forEach var="category" items="${categories}">
+                            <option value="${category.id}" <c:if test="${categoryValue == category.id}">selected</c:if>>
+                                <c:out value="${category.name}" />
+                            </option>
+                        </c:forEach>
+                    </select>
+                    <c:if test="${not empty errors.categoryId}">
+                        <span class="field-error"><c:out value="${errors.categoryId}" /></span>
+                    </c:if>
+                </div>
+
+                <div class="form-field">
+                    <label for="totalCopies">Total copies</label>
+                    <input id="totalCopies" name="totalCopies" type="number" min="0" value="${fn:escapeXml(totalCopiesValue)}" required>
+                    <c:if test="${not empty errors.totalCopies}">
+                        <span class="field-error"><c:out value="${errors.totalCopies}" /></span>
+                    </c:if>
+                </div>
+
+                <div class="form-field">
+                    <label for="availableCopies">Available copies</label>
+                    <input id="availableCopies" name="availableCopies" type="number" min="0" value="${fn:escapeXml(availableCopiesValue)}" required>
+                    <c:if test="${not empty errors.availableCopies}">
+                        <span class="field-error"><c:out value="${errors.availableCopies}" /></span>
+                    </c:if>
+                </div>
+
+                <div class="form-field">
+                    <label for="status">Status</label>
+                    <select id="status" name="status" required>
+                        <option value="">Select status</option>
+                        <c:forEach var="status" items="${statuses}">
+                            <option value="${status.code}" <c:if test="${statusValue == status.code}">selected</c:if>>
+                                <c:out value="${status.displayName}" />
+                            </option>
+                        </c:forEach>
+                    </select>
+                    <c:if test="${not empty errors.status}">
+                        <span class="field-error"><c:out value="${errors.status}" /></span>
+                    </c:if>
+                </div>
+            </div>
+
+            <div class="form-actions">
+                <button class="button button-primary" type="submit">Save</button>
+                <a class="button button-secondary" href="${pageContext.request.contextPath}/books">Cancel</a>
+            </div>
+        </form>
+    </section>
+</main>
+</body>
+</html>

src/main/webapp/WEB-INF/jsp/books/manage.jsp

@@ -0,0 +1,126 @@
+<%@ page contentType="text/html;charset=UTF-8" pageEncoding="UTF-8" %>
+<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
+<%@ taglib prefix="fn" uri="http://java.sun.com/jsp/jstl/functions" %>
+<!doctype html>
+<html lang="en">
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1">
+    <title>Manage Books - MZH Library</title>
+    <link rel="stylesheet" href="${pageContext.request.contextPath}/static/css/app.css">
+</head>
+<body>
+<%@ include file="/WEB-INF/jsp/common/header.jspf" %>
+<main class="page-shell">
+    <section class="dashboard-hero catalog-hero" aria-labelledby="manage-title">
+        <p class="eyebrow">Book Management</p>
+        <h1 id="manage-title">Manage books</h1>
+        <p>Create, update, delete, and review inventory for catalog records.</p>
+        <a class="button button-primary" href="${pageContext.request.contextPath}/books/new">New book</a>
+    </section>
+
+    <c:if test="${not empty successMessage}">
+        <div class="message message-success" role="status">
+            <c:out value="${successMessage}" />
+        </div>
+    </c:if>
+    <c:if test="${not empty errorMessage}">
+        <div class="message message-error" role="alert">
+            <c:out value="${errorMessage}" />
+        </div>
+    </c:if>
+
+    <section class="toolbar-panel" aria-label="Book management search">
+        <form class="search-form" action="${pageContext.request.contextPath}/books" method="get">
+            <div class="search-field">
+                <label for="identifier">Book ID</label>
+                <input id="identifier" name="identifier" type="text" value="${fn:escapeXml(criteria.identifier)}">
+            </div>
+
+            <div class="search-field">
+                <label for="title">Title</label>
+                <input id="title" name="title" type="text" value="${fn:escapeXml(criteria.title)}">
+            </div>
+
+            <div class="search-field">
+                <label for="author">Author</label>
+                <input id="author" name="author" type="text" value="${fn:escapeXml(criteria.author)}">
+            </div>
+
+            <div class="search-field">
+                <label for="categoryId">Category</label>
+                <select id="categoryId" name="categoryId">
+                    <option value="">All categories</option>
+                    <c:forEach var="category" items="${categories}">
+                        <option value="${category.id}" <c:if test="${criteria.categoryId == category.id}">selected</c:if>>
+                            <c:out value="${category.name}" />
+                        </option>
+                    </c:forEach>
+                </select>
+                <c:if test="${not empty errors.categoryId}">
+                    <span class="field-error"><c:out value="${errors.categoryId}" /></span>
+                </c:if>
+            </div>
+
+            <button class="button button-primary" type="submit">Search</button>
+            <a class="button button-secondary" href="${pageContext.request.contextPath}/books">Clear</a>
+            <a class="button button-secondary" href="${pageContext.request.contextPath}/catalog">View catalog</a>
+        </form>
+    </section>
+
+    <section class="table-panel" aria-labelledby="management-results-title">
+        <h2 id="management-results-title">Book records</h2>
+        <c:choose>
+            <c:when test="${empty books}">
+                <p class="empty-state">No book records match the current filters.</p>
+            </c:when>
+            <c:otherwise>
+                <div class="table-scroll">
+                    <table class="data-table">
+                        <thead>
+                        <tr>
+                            <th scope="col">Book ID</th>
+                            <th scope="col">Title</th>
+                            <th scope="col">Author</th>
+                            <th scope="col">Category</th>
+                            <th scope="col">Copies</th>
+                            <th scope="col">Status</th>
+                            <th scope="col">Actions</th>
+                        </tr>
+                        </thead>
+                        <tbody>
+                        <c:forEach var="book" items="${books}">
+                            <tr>
+                                <td><c:out value="${book.identifier}" /></td>
+                                <td><c:out value="${book.title}" /></td>
+                                <td><c:out value="${book.author}" /></td>
+                                <td><c:out value="${book.categoryName}" /></td>
+                                <td><c:out value="${book.availableCopies}" /> / <c:out value="${book.totalCopies}" /></td>
+                                <td>
+                                    <span class="status-pill status-${book.status.code}">
+                                        <c:out value="${book.status.displayName}" />
+                                    </span>
+                                </td>
+                                <td>
+                                    <div class="table-actions">
+                                        <a class="button button-secondary"
+                                           href="${pageContext.request.contextPath}/books/edit?id=${book.id}">Edit</a>
+                                        <form action="${pageContext.request.contextPath}/books/delete"
+                                              method="post"
+                                              onsubmit="return confirm('Delete this book record?');">
+                                            <input type="hidden" name="id" value="${book.id}">
+                                            <button class="button button-danger" type="submit">Delete</button>
+                                        </form>
+                                    </div>
+                                </td>
+                            </tr>
+                        </c:forEach>
+                        </tbody>
+                    </table>
+                </div>
+            </c:otherwise>
+        </c:choose>
+    </section>
+</main>
+</body>
+</html>

src/main/webapp/WEB-INF/jsp/common/header.jspf

@@ -4,11 +4,13 @@
     <c:if test="${not empty sessionScope.authenticatedUser}">
         <nav class="top-nav" aria-label="Primary">
             <a href="${pageContext.request.contextPath}/dashboard">Dashboard</a>
+            <a href="${pageContext.request.contextPath}/catalog">Catalog</a>
             <c:if test="${sessionScope.userRole == 'administrator'}">
                 <a href="${pageContext.request.contextPath}/admin/home">Admin</a>
             </c:if>
             <c:if test="${sessionScope.userRole == 'administrator' or sessionScope.userRole == 'librarian'}">
                 <a href="${pageContext.request.contextPath}/librarian/home">Librarian</a>
+                <a href="${pageContext.request.contextPath}/books">Books</a>
             </c:if>
             <a href="${pageContext.request.contextPath}/reader/home">Reader</a>
             <span class="user-pill">

src/main/webapp/WEB-INF/jsp/dashboard.jsp

@@ -34,11 +34,23 @@
                 <p>Book, reader, borrowing, return, renewal, and overdue entry point.</p>
                 <a class="button button-secondary" href="${pageContext.request.contextPath}/librarian/home">Open</a>
             </article>
+
+            <article class="workspace-card">
+                <h2>Book Management</h2>
+                <p>Create, update, delete, and review book inventory records.</p>
+                <a class="button button-secondary" href="${pageContext.request.contextPath}/books">Open</a>
+            </article>
         </c:if>
 
+        <article class="workspace-card">
+            <h2>Book Catalog</h2>
+            <p>Search books by title, author, category, or book identifier.</p>
+            <a class="button button-secondary" href="${pageContext.request.contextPath}/catalog">Search</a>
+        </article>
+
         <article class="workspace-card">
             <h2>Reader Center</h2>
-            <p>Catalog search and reader self-service entry point.</p>
+            <p>Reader self-service entry point.</p>
             <a class="button button-secondary" href="${pageContext.request.contextPath}/reader/home">Open</a>
         </article>
     </section>

src/main/webapp/WEB-INF/jsp/role-home.jsp

@@ -19,6 +19,22 @@
         <p><c:out value="${areaSummary}" /></p>
         <a class="button button-primary" href="${pageContext.request.contextPath}/dashboard">Back to dashboard</a>
     </section>
+
+    <section class="card-grid role-actions" aria-label="Workspace actions">
+        <article class="workspace-card">
+            <h2>Book Catalog</h2>
+            <p>Search available collection records by title, author, category, or book identifier.</p>
+            <a class="button button-secondary" href="${pageContext.request.contextPath}/catalog">Search catalog</a>
+        </article>
+
+        <c:if test="${sessionScope.userRole == 'administrator' or sessionScope.userRole == 'librarian'}">
+            <article class="workspace-card">
+                <h2>Book Management</h2>
+                <p>Create, update, delete, and review inventory fields for book records.</p>
+                <a class="button button-secondary" href="${pageContext.request.contextPath}/books">Manage books</a>
+            </article>
+        </c:if>
+    </section>
 </main>
 </body>
 </html>

src/main/webapp/WEB-INF/web.xml

@@ -75,6 +75,28 @@
         <url-pattern>/reader/home</url-pattern>
     </servlet-mapping>
 
+    <servlet>
+        <servlet-name>BookCatalogServlet</servlet-name>
+        <servlet-class>com.mzh.library.controller.BookCatalogServlet</servlet-class>
+    </servlet>
+    <servlet-mapping>
+        <servlet-name>BookCatalogServlet</servlet-name>
+        <url-pattern>/catalog</url-pattern>
+    </servlet-mapping>
+
+    <servlet>
+        <servlet-name>BookManagementServlet</servlet-name>
+        <servlet-class>com.mzh.library.controller.BookManagementServlet</servlet-class>
+    </servlet>
+    <servlet-mapping>
+        <servlet-name>BookManagementServlet</servlet-name>
+        <url-pattern>/books</url-pattern>
+        <url-pattern>/books/new</url-pattern>
+        <url-pattern>/books/edit</url-pattern>
+        <url-pattern>/books/update</url-pattern>
+        <url-pattern>/books/delete</url-pattern>
+    </servlet-mapping>
+
     <servlet>
         <servlet-name>UnauthorizedServlet</servlet-name>
         <servlet-class>com.mzh.library.controller.UnauthorizedServlet</servlet-class>

src/main/webapp/static/css/app.css

@@ -8,6 +8,8 @@
     --color-primary: #256f6c;
     --color-primary-strong: #1b5654;
     --color-accent: #b54238;
+    --color-success: #2f6f3e;
+    --color-warning: #8a5a00;
     --shadow-panel: 0 18px 45px rgba(28, 39, 49, 0.12);
 }
 
@@ -91,7 +93,10 @@ a {
 .login-panel,
 .notice-panel,
 .dashboard-hero,
-.workspace-card {
+.workspace-card,
+.toolbar-panel,
+.table-panel,
+.form-panel {
     border: 1px solid var(--color-border);
     border-radius: 8px;
     background: var(--color-panel);
@@ -184,6 +189,15 @@ h2 {
     background: #ffffff;
 }
 
+.button-danger {
+    color: #ffffff;
+    background: var(--color-accent);
+}
+
+.button-danger:hover {
+    background: #8f3028;
+}
+
 .message {
     margin-bottom: 16px;
     padding: 10px 12px;
@@ -197,6 +211,12 @@ h2 {
     background: #fff0ee;
 }
 
+.message-success {
+    color: #1f572e;
+    border: 1px solid rgba(47, 111, 62, 0.3);
+    background: #effaf1;
+}
+
 .page-shell {
     padding: 36px 0 56px;
 }
@@ -239,6 +259,173 @@ h2 {
     padding: 28px;
 }
 
+.role-actions {
+    margin-top: 24px;
+}
+
+.catalog-hero {
+    display: flex;
+    align-items: flex-start;
+    justify-content: space-between;
+    gap: 18px;
+    flex-wrap: wrap;
+}
+
+.catalog-hero .button {
+    margin-top: 0;
+}
+
+.toolbar-panel,
+.table-panel,
+.form-panel {
+    padding: 24px;
+    margin-bottom: 24px;
+}
+
+.search-form {
+    display: grid;
+    grid-template-columns: repeat(4, minmax(120px, 1fr)) auto auto auto;
+    gap: 10px;
+    align-items: end;
+}
+
+.search-field {
+    display: grid;
+    gap: 6px;
+}
+
+.search-form label {
+    color: var(--color-muted);
+    font-size: 13px;
+    font-weight: 700;
+}
+
+.search-form input,
+.search-form select,
+.book-form input,
+.book-form select {
+    width: 100%;
+    min-height: 42px;
+    padding: 9px 11px;
+    border: 1px solid var(--color-border);
+    border-radius: 6px;
+    background: #ffffff;
+    font: inherit;
+}
+
+.search-form input:focus,
+.search-form select:focus,
+.book-form input:focus,
+.book-form select:focus {
+    outline: 3px solid rgba(37, 111, 108, 0.18);
+    border-color: var(--color-primary);
+}
+
+.table-scroll {
+    width: 100%;
+    overflow-x: auto;
+}
+
+.data-table {
+    width: 100%;
+    min-width: 760px;
+    border-collapse: collapse;
+    font-size: 14px;
+}
+
+.data-table th,
+.data-table td {
+    padding: 12px 10px;
+    text-align: left;
+    border-bottom: 1px solid var(--color-border);
+    vertical-align: middle;
+}
+
+.data-table th {
+    color: var(--color-muted);
+    font-size: 13px;
+    font-weight: 700;
+    background: #f8fafc;
+}
+
+.empty-state {
+    margin-bottom: 0;
+    color: var(--color-muted);
+}
+
+.status-pill {
+    display: inline-flex;
+    min-height: 28px;
+    align-items: center;
+    padding: 4px 9px;
+    border-radius: 999px;
+    font-size: 12px;
+    font-weight: 700;
+}
+
+.status-available {
+    color: var(--color-success);
+    background: #edf8ef;
+}
+
+.status-unavailable {
+    color: var(--color-warning);
+    background: #fff7e5;
+}
+
+.status-archived {
+    color: var(--color-muted);
+    background: #eef1f5;
+}
+
+.table-actions {
+    display: flex;
+    gap: 8px;
+    align-items: center;
+    flex-wrap: wrap;
+}
+
+.table-actions form {
+    margin: 0;
+}
+
+.form-panel {
+    max-width: 860px;
+}
+
+.book-form {
+    display: grid;
+    gap: 20px;
+}
+
+.form-grid {
+    display: grid;
+    grid-template-columns: repeat(2, minmax(0, 1fr));
+    gap: 16px;
+}
+
+.form-field {
+    display: grid;
+    gap: 6px;
+}
+
+.form-field label {
+    color: var(--color-muted);
+    font-size: 14px;
+    font-weight: 700;
+}
+
+.field-error {
+    color: #7a211a;
+    font-size: 13px;
+}
+
+.form-actions {
+    display: flex;
+    gap: 10px;
+    flex-wrap: wrap;
+}
+
 @media (max-width: 720px) {
     .app-header {
         align-items: flex-start;
@@ -257,7 +444,15 @@ h2 {
     .login-panel,
     .notice-panel,
     .dashboard-hero,
-    .workspace-card {
+    .workspace-card,
+    .toolbar-panel,
+    .table-panel,
+    .form-panel {
         box-shadow: none;
     }
+
+    .search-form,
+    .form-grid {
+        grid-template-columns: 1fr;
+    }
 }

src/test/java/com/mzh/library/service/BookServiceCheck.java

@@ -0,0 +1,219 @@
+package com.mzh.library.service;
+
+import com.mzh.library.dao.BookDao;
+import com.mzh.library.entity.AuthenticatedUser;
+import com.mzh.library.entity.Book;
+import com.mzh.library.entity.BookCategory;
+import com.mzh.library.entity.BookSearchCriteria;
+import com.mzh.library.entity.BookStatus;
+import com.mzh.library.entity.Permission;
+import com.mzh.library.entity.Role;
+import com.mzh.library.exception.DaoException;
+import com.mzh.library.service.impl.BookServiceImpl;
+
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.EnumSet;
+import java.util.LinkedHashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Optional;
+import java.util.logging.Level;
+import java.util.logging.Logger;
+
+public final class BookServiceCheck {
+    private static final String UNAVAILABLE_MESSAGE =
+        "Book service is temporarily unavailable. Please try again later.";
+
+    private BookServiceCheck() {
+    }
+
+    public static void main(String[] args) {
+        Logger.getLogger(BookServiceImpl.class.getName()).setLevel(Level.OFF);
+
+        InMemoryBookDao dao = new InMemoryBookDao();
+        BookService service = new BookServiceImpl(dao);
+        AuthenticatedUser librarian = user(10L, Role.LIBRARIAN);
+        AuthenticatedUser reader = user(20L, Role.READER);
+
+        ServiceResult<Long> invalidInventory = service.createBook(librarian,
+            book(0L, "BK-1000", "Invalid Copies", "Test Author", 1L, 2, 3, BookStatus.AVAILABLE));
+        require(!invalidInventory.isSuccessful(), "invalid inventory should fail");
+        require(invalidInventory.getErrors().containsKey("availableCopies"),
+            "available copies greater than total should be rejected");
+
+        ServiceResult<Long> denied = service.createBook(reader,
+            book(0L, "BK-1001", "Reader Write", "Test Author", 1L, 1, 1, BookStatus.AVAILABLE));
+        require(!denied.isSuccessful(), "reader write should fail");
+        require("You do not have permission to manage books.".equals(denied.getMessage()),
+            "reader write should return permission message");
+
+        ServiceResult<Long> created = service.createBook(librarian,
+            book(0L, "BK-1002", "Service Test", "Test Author", 1L, 2, 1, BookStatus.AVAILABLE));
+        require(created.isSuccessful(), "librarian should create a valid book");
+        long createdId = created.getData();
+
+        ServiceResult<Long> duplicate = service.createBook(librarian,
+            book(0L, "BK-1002", "Duplicate", "Test Author", 1L, 1, 1, BookStatus.AVAILABLE));
+        require(!duplicate.isSuccessful(), "duplicate identifier should fail");
+        require(duplicate.getErrors().containsKey("identifier"), "duplicate should target identifier field");
+
+        ServiceResult<Void> updated = service.updateBook(librarian,
+            book(createdId, "BK-1003", "Service Test Updated", "Test Author", 1L, 3, 3, BookStatus.AVAILABLE));
+        require(updated.isSuccessful(), "librarian should update a valid book");
+        require(dao.findById(createdId).get().getAvailableCopies() == 3, "update should persist available copies");
+
+        ServiceResult<List<Book>> search = service.searchBooks(new BookSearchCriteria("BK-1003", "", "", null));
+        require(search.isSuccessful(), "search should succeed");
+        require(search.getData().size() == 1, "search should find updated identifier");
+
+        ServiceResult<Void> deleted = service.deleteBook(librarian, createdId);
+        require(deleted.isSuccessful(), "librarian should delete a book");
+        require(!dao.findById(createdId).isPresent(), "delete should remove the record");
+
+        BookService failingService = new BookServiceImpl(new FailingBookDao());
+        ServiceResult<List<Book>> unavailable = failingService.searchBooks(new BookSearchCriteria());
+        require(!unavailable.isSuccessful(), "DAO failure should not escape service");
+        require(UNAVAILABLE_MESSAGE.equals(unavailable.getMessage()), "DAO failure should map to safe message");
+    }
+
+    private static AuthenticatedUser user(long id, Role role) {
+        return new AuthenticatedUser(id, role.getCode(), role.getDisplayName(), role,
+            role == Role.READER
+                ? EnumSet.of(Permission.VIEW_CATALOG, Permission.BORROW_BOOKS)
+                : EnumSet.of(Permission.MANAGE_BOOKS, Permission.VIEW_CATALOG));
+    }
+
+    private static Book book(long id, String identifier, String title, String author, long categoryId,
+                             int totalCopies, int availableCopies, BookStatus status) {
+        Book book = new Book();
+        book.setId(id);
+        book.setIdentifier(identifier);
+        book.setTitle(title);
+        book.setAuthor(author);
+        book.setCategoryId(categoryId);
+        book.setTotalCopies(totalCopies);
+        book.setAvailableCopies(availableCopies);
+        book.setStatus(status);
+        return book;
+    }
+
+    private static void require(boolean condition, String message) {
+        if (!condition) {
+            throw new AssertionError(message);
+        }
+    }
+
+    private static final class InMemoryBookDao implements BookDao {
+        private final Map<Long, Book> books = new LinkedHashMap<>();
+        private long nextId = 1L;
+
+        @Override
+        public List<BookCategory> findAllCategories() {
+            BookCategory category = new BookCategory();
+            category.setId(1L);
+            category.setName("Computer Science");
+            return Collections.singletonList(category);
+        }
+
+        @Override
+        public List<Book> search(BookSearchCriteria criteria) {
+            List<Book> matches = new ArrayList<>();
+            for (Book book : books.values()) {
+                if (matches(criteria.getIdentifier(), book.getIdentifier())
+                    && matches(criteria.getTitle(), book.getTitle())
+                    && matches(criteria.getAuthor(), book.getAuthor())
+                    && (criteria.getCategoryId() == null || criteria.getCategoryId() == book.getCategoryId())) {
+                    matches.add(copy(book));
+                }
+            }
+            return matches;
+        }
+
+        @Override
+        public Optional<Book> findById(long id) {
+            return Optional.ofNullable(books.get(id)).map(this::copy);
+        }
+
+        @Override
+        public Optional<Book> findByIdentifier(String identifier) {
+            for (Book book : books.values()) {
+                if (book.getIdentifier().equals(identifier)) {
+                    return Optional.of(copy(book));
+                }
+            }
+            return Optional.empty();
+        }
+
+        @Override
+        public long create(Book book) {
+            long id = nextId++;
+            Book stored = copy(book);
+            stored.setId(id);
+            books.put(id, stored);
+            return id;
+        }
+
+        @Override
+        public boolean update(Book book) {
+            if (!books.containsKey(book.getId())) {
+                return false;
+            }
+            books.put(book.getId(), copy(book));
+            return true;
+        }
+
+        @Override
+        public boolean delete(long id) {
+            return books.remove(id) != null;
+        }
+
+        private boolean matches(String filter, String value) {
+            return filter == null || filter.isEmpty() || value.contains(filter);
+        }
+
+        private Book copy(Book source) {
+            Book copy = book(source.getId(), source.getIdentifier(), source.getTitle(), source.getAuthor(),
+                source.getCategoryId(), source.getTotalCopies(), source.getAvailableCopies(), source.getStatus());
+            copy.setCategoryName(source.getCategoryName());
+            return copy;
+        }
+    }
+
+    private static final class FailingBookDao implements BookDao {
+        @Override
+        public List<BookCategory> findAllCategories() {
+            throw new DaoException("Simulated category failure", null);
+        }
+
+        @Override
+        public List<Book> search(BookSearchCriteria criteria) {
+            throw new DaoException("Simulated search failure", null);
+        }
+
+        @Override
+        public Optional<Book> findById(long id) {
+            throw new DaoException("Simulated find failure", null);
+        }
+
+        @Override
+        public Optional<Book> findByIdentifier(String identifier) {
+            throw new DaoException("Simulated find failure", null);
+        }
+
+        @Override
+        public long create(Book book) {
+            throw new DaoException("Simulated create failure", null);
+        }
+
+        @Override
+        public boolean update(Book book) {
+            throw new DaoException("Simulated update failure", null);
+        }
+
+        @Override
+        public boolean delete(long id) {
+            throw new DaoException("Simulated delete failure", null);
+        }
+    }
+}