使用ThreadLocal保存用户登录信息

╰半橙微兮° 2022-08-14 01:37 273阅读 0赞

最近在使用WebSocket来进行消息推送，一，系统推送。二，用户对用户进行推送。

SystemSession类：

import com.srkj.code.model.User;
    /**
     * 线程共享类
     * @author 胡汉三 
     *
     * 2014-11-18 下午2:40:27
     */
    public class SystemSession {
    	//声明
    	private static ThreadLocal<User> local = new ThreadLocal<User>();  
    	/**
    	 * 赋值
    	 * @param session
    	 */
        public static void set(User session) {  
            local.set(session);  
        }  
        /**
         * 取值
         * @return
         */
        public static User get() {  
            return local.get();  
        }    
        /**
         * 移除
         */
        public static void remove(){
        	local.remove();
        }
    }

使用过滤器拦截用户请求：

import java.io.IOException;
    
    import javax.servlet.Filter;
    import javax.servlet.FilterChain;
    import javax.servlet.FilterConfig;
    import javax.servlet.ServletException;
    import javax.servlet.ServletRequest;
    import javax.servlet.ServletResponse;
    import javax.servlet.http.HttpServletRequest;
    
    import com.srkj.code.model.User;
    /**
     * Session过滤器
     * @author 胡汉三
     *
     * 2014-11-18 下午2:41:35
     */
    public class MyFilter implements Filter{
    
    	public void destroy() {}
    	
    	public void doFilter(ServletRequest req, ServletResponse res,
    			FilterChain filterChain) throws IOException, ServletException {
    		HttpServletRequest request = (HttpServletRequest)req;  
    	    User userSession = (User)request.getSession().getAttribute("userInfo");  
    	    if (userSession != null) {  
    	    	//重新设值session
    	        request.getSession().setAttribute("userInfo", userSession);  
    	    }    
    	    filterChain.doFilter(req, res);    
    		
    	}
    
    	public void init(FilterConfig arg0) throws ServletException {}
    	
    }

web.xml配置：

<filter>
            <filter-name>myFilter</filter-name>
            <filter-class>com.srkj.code.util.MyFilter</filter-class>
        </filter>
        <filter-mapping>
            <filter-name>myFilter</filter-name> 
            <url-pattern>/*</url-pattern>
        </filter-mapping>

在配置一个用户session状态变更的监听类MyHttpSessionAttributeListener：

import javax.servlet.http.HttpSessionAttributeListener;
    import javax.servlet.http.HttpSessionBindingEvent;
    
    
    import com.srkj.code.model.User;
    /**
     * Session监听器
     * @author 胡汉三
     * 
     * 2014-11-18 下午2:42:02
     */
    public class MyHttpSessionAttributeListener implements HttpSessionAttributeListener {  
    	/**
    	 * 添加Session
    	 */
    	public void attributeAdded(HttpSessionBindingEvent event) {  
            if ("userInfo".equals(event.getName())) {  
                SystemSession.set((User)event.getValue());  
            }  
        }  
      
    	/**
    	 * 替代Session
    	 */
        public void attributeReplaced(HttpSessionBindingEvent event) {  
            if ("userInfo".equals(event.getName())) {  
                SystemSession.set((User)event.getValue());  
            }  
        }
    
        /**
         * 销毁Session
         */
    	public void attributeRemoved(HttpSessionBindingEvent event) {
    		if("userInfo".equals(event.getName())){
    			SystemSession.remove();  
    		}  
    	}     
    }

web.xml监听配置：

<listener>
    		<listener-class>com.srkj.code.util.MyHttpSessionAttributeListener</listener-class>
    	 </listener>

这样之后，就可以在程序中直接SystemSession.get() 就能得到用户对象，如：

public ChatAnnotation() {
    		nickname = SystemSession.get().getUuuid();  
    	}