添加过滤器

src/com/landaiqing/filter/UserSessionFilter.java

@@ -0,0 +1,53 @@
+package com.landaiqing.filter;
+
+
+import jakarta.servlet.*;
+import jakarta.servlet.annotation.WebFilter;
+import jakarta.servlet.annotation.WebServlet;
+import jakarta.servlet.http.HttpServletRequest;
+import jakarta.servlet.http.HttpServletResponse;
+import jakarta.servlet.http.HttpSession;
+
+import java.io.IOException;
+
+/**
+ * @author 余胜军
+ * @ClassName UserSessionFilter
+ * @qq 644064779
+ * @addres www.mayikt.com
+ * 微信:yushengjun644
+ */
+@WebFilter("/*")// 过滤器所有的请求
+public class UserSessionFilter implements Filter {
+    private String[] excludeUrls = new String[]{"/login", "/register", "/VerifycodeServlet"};
+
+    @Override
+    public void doFilter(ServletRequest servletRequest, ServletResponse servletResponse, FilterChain filterChain) throws IOException, ServletException {
+        // 从session获取到用户的会话信息 判断用户是否登录过
+        HttpServletRequest httpServletRequest = (HttpServletRequest) servletRequest;
+        HttpServletResponse httpServletResponse = (HttpServletResponse) servletResponse;
+        String contextPath = httpServletRequest.getContextPath();
+        // 定义一个数组 哪些 请求是需要排除的
+        for (int i = 0; i < excludeUrls.length; i++) {
+            String excludeUrl = contextPath + excludeUrls[i];
+            String requestURI = httpServletRequest.getRequestURI();
+            if (excludeUrl.equals(requestURI)) {
+                // 放行请求
+                filterChain.doFilter(httpServletRequest, httpServletResponse);
+                return;
+            }
+        }
+        // 排除请求
+        HttpSession session = httpServletRequest.getSession();
+        Object user = session.getAttribute("user");
+        if (user == null) {
+            // 当前用户没有登录或者登录会话失效
+            // 重定向到登录页面
+            httpServletResponse.sendRedirect(contextPath+"/login");
+            return;
+        }
+        // 用户已经登录了 正常放行请求
+        filterChain.doFilter(httpServletRequest, httpServletResponse);
+    }
+}
+