springBoot创建session监听器

以你之姓@ 2023-10-18 14:33 129阅读 0赞

## 1.建立session监听，要实现HttpSessionListener接口,加上注解@WebListener ##

@WebListener
     public class SessionListener implements HttpSessionListener {
         
            public void sessionCreated(HttpSessionEvent httpSessionEvent) {
          
                HttpSession session = httpSessionEvent.getSession();  
                myc.addSession(session);  
            }  
    
            public void sessionDestroyed(HttpSessionEvent httpSessionEvent) {
          
                HttpSession session = httpSessionEvent.getSession();  
                myc.delSession(session);  
            }
     }

## 2.启动类加上注解@ServletComponentScan，这样才能扫描到监听器 ##

#### 简单说下，javaWeb中配置监听器在web.xml中加上 ####

<listener> 
      <listener-class>zjq.listener.SessionListener</listener-class> 
     </listener>

## 3.下面举一个通过sessionId获取会话的例子来具体阐述 ##

#### 1.先新建一个MySessionContext类 ####

package com.boot.zhiyi.util;
    
    import java.util.HashMap;
    
    import javax.servlet.http.HttpSession;
    
    public class MySessionContext {
        
    	private static MySessionContext instance;
    	private HashMap<String, HttpSession> sessionMap;
    
    	private MySessionContext() {
        
    		sessionMap = new HashMap<String, HttpSession>();
    	}
    
    	public static MySessionContext getInstance() {
        
    		if (instance == null) {
        
    			instance = new MySessionContext();
    		}
    		return instance;
    	}
    
    	public synchronized void addSession(HttpSession session) {
        
    		if (session != null) {
        
    			sessionMap.put(session.getId(), session);
    		}
    	}
    
    	public synchronized void delSession(HttpSession session) {
        
    		if (session != null) {
        
    			sessionMap.remove(session.getId());
    		}
    	}
    
    	public synchronized HttpSession getSession(String sessionID) {
        
    		if (sessionID == null) {
        
    			return null;
    		}
    		return sessionMap.get(sessionID);
    	}
    }

这个代码可以直接拿来copy，不用做任何修改

#### 2.在刚刚你创建的SessionListener监听器里面，修改你实现的两个方法： ####

*  sessionCreated
 *  sessionDestroyed  
    具体如下：

package com.boot.zhiyi.listerner;
    
    import javax.servlet.annotation.WebListener;
    import javax.servlet.http.HttpSession;
    import javax.servlet.http.HttpSessionEvent;
    import javax.servlet.http.HttpSessionListener;
    
    import com.boot.zhiyi.util.MySessionContext;
    @WebListener
    public class SessionListener implements  HttpSessionListener{
        
    	 private MySessionContext myc = MySessionContext.getInstance();  
    	@Override
    	public void sessionCreated(HttpSessionEvent se) {
        
    		HttpSession session = se.getSession();  
            myc.addSession(session); //将你创建的session会话加入到map接口中
            //下面这句代码用于设置session的声明周期
            session.setMaxInactiveInterval(3);//以秒为单位，即在没有活动30分钟后，session将失效
    	}
    
    	@Override
    	public void sessionDestroyed(HttpSessionEvent se) {
        
    		// TODO Auto-generated method stub
    		 HttpSession session = se.getSession();  
             myc.delSession(session);  //此处用于将你的session对象从map中移除
    	}
    	
    }

#### 3.具体获取sessionId的方法：在Controller中： ####

@ResponseBody
    	@GetMapping("/get")
    	public Map<String, Object> get(@RequestParam("sid") String sid, HttpServletResponse response,HttpServletRequest request) {
        
    		response.setHeader("Access-Control-Allow-Origin", "*");
    		Map<String, Object> map = new HashMap<String, Object>();
    		MySessionContext myc= MySessionContext.getInstance();  
    //		HttpSession session = request.getSession().getSessionContext().getSession(sid); 这个方法已经被废弃
    		HttpSession session = myc.getSession(sid);  //此处就是通过sessionId获取session信息
    		if(session!=null) {
        
    			String user=String.valueOf(session.getAttribute("user"));
    			String keySecret=String.valueOf(session.getAttribute("keySecret"));
    			map.put("user", user);
    			map.put("keySecret", keySecret);
    		}
    				
    		return map;
    	}