一个简单的超市订单管理系统（4）-用户注销和权限拦截

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一个简单的超市订单管理系统（4）-用户注销和权限拦截

1.注销功能：移除session，返回登录页面即可

　　（1）编写移除注销功能的servlet

 1 package com.xiaoma.servlet.user;
 2 
 3 import com.xiaoma.util.Constants;
 4 
 5 import javax.servlet.ServletException;
 6 import javax.servlet.http.HttpServlet;
 7 import javax.servlet.http.HttpServletRequest;
 8 import javax.servlet.http.HttpServletResponse;
 9 import java.io.IOException;
10 
11 public class LogoutServlet extends HttpServlet {
12     @Override
13     protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
14         //移除session
15         req.getSession().removeAttribute(Constants.USER_SESSION);
16         //重定向到登录页面
17         resp.sendRedirect(req.getContextPath()+"/login.jsp");
18     }
19 
20     @Override
21     protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
22         doGet(req, resp);
23     }
24 }

　　（2）在web.xml中注册我们的servlet，注意这里的url-patten是走的前端的jsp/common/head.jsp下的退出走的那个url

　　（3）效果图

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2. 登录权限拦截

　　（1）在filter文件夹下创建一个SysFilter类文件，用来进行登录拦截，所需的error.jsp页面链接：https://pan.baidu.com/s/1UKtUbRBphFyIlk6RU9aR9g提取码：5210

 1 package com.xiaoma.filter;
 2 
 3 import com.xiaoma.pojo.User;
 4 import com.xiaoma.util.Constants;
 5 
 6 import javax.servlet.*;
 7 import javax.servlet.http.HttpServletRequest;
 8 import javax.servlet.http.HttpServletResponse;
 9 import java.io.IOException;
10 
11 
12 public class SysFilter implements Filter {
13 
14     @Override
15     public void init(FilterConfig filterConfig) throws ServletException {
16 
17     }
18 
19     @Override
20     public void doFilter(ServletRequest req, ServletResponse resp, FilterChain filterChain) throws IOException, ServletException {
21         //request用来获取session，request用来重定向
22         HttpServletRequest request=(HttpServletRequest) req;
23         HttpServletResponse response=(HttpServletResponse) resp;
24 
25         //获取session
26         User user=(User) request.getSession().getAttribute(Constants.USER_SESSION);
27 
28         //用户session为空，就说明用户已经注销了，或者未登录
29         if (user == null) {
30             response.sendRedirect(((HttpServletRequest) req).getContextPath()+"/error.jsp");
31         }else{
32             filterChain.doFilter(req,resp);
33         }
34     }
35 
36     @Override
37     public void destroy() {
38 
39     }
40 }

　　（2）在web.xml中注册过滤器

1     <!--注册权限拦截过滤器-->
2     <filter>
3         <filter-name>SysFilter</filter-name>
4         <filter-class>com.xiaoma.filter.SysFilter</filter-class>
5     </filter>
6     <filter-mapping>
7         <filter-name>SysFilter</filter-name>
8         <url-pattern>/jsp/*</url-pattern>
9     </filter-mapping>

　　（3）运行测试效果

来源：https://www.cnblogs.com/XiaoMaGuai/p/15422003.html

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