监听器HttpSessionBindingListener——监听Session属性的绑定、解绑

素颜马尾好姑娘i 2022-03-18 03:01 217阅读 0赞

### 文章目录 ###

*   *   *  一、项目结构
         *  二、用户类
         *  三、servlet测试
         *  四、部署及运行结果

### 一、项目结构 ###

项目实现：监听对象是否绑定到session  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hqdTIy_size_16_color_FFFFFF_t_70]

### 二、用户类 ###

写一个用户类，实现session绑定监听器  
**User.java**

package net.test.bean;
    
    import javax.servlet.http.HttpSessionBindingEvent;
    import javax.servlet.http.HttpSessionBindingListener;
    
    public class User implements HttpSessionBindingListener {
    
        private int id;
        private String name;
    
        public int getId() {
            return id;
        }
    
        public void setId(int id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
    
        @Override
        public void valueBound(HttpSessionBindingEvent httpSessionBindingEvent) {
            //绑定
            System.out.println("对象被绑定了");
        }
    
        @Override
        public void valueUnbound(HttpSessionBindingEvent httpSessionBindingEvent) {
            //解绑
            System.out.println("对象被解绑了");
    
        }
    }

### 三、servlet测试 ###

写一个servlet，用来测试用户绑定的监听功能  
TestUserServlet.java

package net.test.servlet;
    
    import net.test.bean.User;
    
    import javax.servlet.ServletException;
    import javax.servlet.annotation.WebServlet;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    import javax.servlet.http.HttpSession;
    import java.io.IOException;
    
    @WebServlet(name = "TestUserServlet",urlPatterns = "/testBind")
    public class TestUserServlet extends HttpServlet {
        protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    
        }
    
        protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            HttpSession session = request.getSession();
            User user = new User();
            user.setId(1);
            user.setName("小明");
            //绑定对象
            session.setAttribute("user",user);
    
            //解绑对象
            session.removeAttribute("user");
        }
    }

### 四、部署及运行结果 ###

部署  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hqdTIy_size_16_color_FFFFFF_t_70 1]  
浏览器中访问：[http://localhost:8081/testBind][http_localhost_8081_testBind]  
控制台出现以下结果：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hqdTIy_size_16_color_FFFFFF_t_70 2]

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hqdTIy_size_16_color_FFFFFF_t_70]: /images/20220318/54e533ffa71347f4a148fd426ee0e005.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hqdTIy_size_16_color_FFFFFF_t_70 1]: /images/20220318/3ae0e8b23a4f46c6b158a61054fe44ab.png
[http_localhost_8081_testBind]: http://localhost:8081/testBind
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2hqdTIy_size_16_color_FFFFFF_t_70 2]: /images/20220318/82c8f7ef3ae54b2b92dc45c9e9acebda.png