借书/还书/续借/逾期管理

src/main/java/com/mzh/library/util/JdbcUtil.java

@@ -13,6 +13,11 @@ public final class JdbcUtil {
     private static final String CONFIG_FILE = "db.properties";
     private static final String DEFAULT_DRIVER = "com.mysql.cj.jdbc.Driver";
 
+    @FunctionalInterface
+    public interface TransactionCallback<T> {
+        T execute(Connection connection) throws SQLException;
+    }
+
     private JdbcUtil() {
     }
 
@@ -31,6 +36,33 @@ public final class JdbcUtil {
         }
     }
 
+    public static <T> T executeInTransaction(TransactionCallback<T> callback) {
+        try (Connection connection = getConnection()) {
+            connection.setAutoCommit(false);
+            try {
+                T result = callback.execute(connection);
+                connection.commit();
+                return result;
+            } catch (SQLException ex) {
+                rollbackQuietly(connection);
+                throw new DaoException("Unable to complete database transaction", ex);
+            } catch (RuntimeException ex) {
+                rollbackQuietly(connection);
+                throw ex;
+            }
+        } catch (SQLException ex) {
+            throw new DaoException("Unable to complete database transaction", ex);
+        }
+    }
+
+    private static void rollbackQuietly(Connection connection) {
+        try {
+            connection.rollback();
+        } catch (SQLException ignored) {
+            // Preserve the original transaction failure for callers and logs.
+        }
+    }
+
     private static Properties loadProperties() {
         try (InputStream inputStream = Thread.currentThread()
             .getContextClassLoader()