Initial commit

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

@@ -0,0 +1,36 @@
+package com.mzh.library.controller;
+
+import com.mzh.library.entity.AuthenticatedUser;
+import com.mzh.library.util.SessionAttributes;
+
+import java.io.IOException;
+import java.util.logging.Logger;
+
+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 LogoutServlet extends HttpServlet {
+    private static final Logger LOGGER = Logger.getLogger(LogoutServlet.class.getName());
+
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        HttpSession session = request.getSession(false);
+        if (session != null) {
+            AuthenticatedUser user = currentUser(session);
+            if (user != null) {
+                LOGGER.info("Logout userId=" + user.getId() + " role=" + user.getRole().getCode());
+            }
+            session.invalidate();
+        }
+
+        response.sendRedirect(request.getContextPath() + "/login");
+    }
+
+    private AuthenticatedUser currentUser(HttpSession session) {
+        Object value = session.getAttribute(SessionAttributes.AUTHENTICATED_USER);
+        return value instanceof AuthenticatedUser ? (AuthenticatedUser) value : null;
+    }
+}