Spring WebSocket实现消息推送

Spring WebSocket实现消息推送

第一步： 添加Spring WebSocket的依赖jar包

（注：这里使用maven方式添加 手动添加的同学请自行下载相应jar包放到lib目录）

        
            org.springframework
            spring-websocket
            ${spring.version}
        
        
            org.springframework
            spring-messaging
            ${spring.version}
                

 

第二步：建立一个类实现WebSocketConfigurer接口

package com.quicksand.push;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
import org.springframework.web.socket.handler.TextWebSocketHandler;


@Configuration
@EnableWebMvc
@EnableWebSocket
public class SpringWebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer {
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(webSocketHandler(),"/websocket/socketServer.do").addInterceptors(new SpringWebSocketHandlerInterceptor());
        registry.addHandler(webSocketHandler(), "/sockjs/socketServer.do").addInterceptors(new SpringWebSocketHandlerInterceptor()).withSockJS();
    }
 
    @Bean
    public TextWebSocketHandler webSocketHandler(){
        return new SpringWebSocketHandler();
    }

}

 

 第三步：继承WebSocketHandler对象。该对象提供了客户端连接,关闭,错误,发送等方法,重写这几个方法即可实现自定义业务逻辑

package com.quicksand.push;

import java.io.IOException;
import java.util.ArrayList;
import org.apache.log4j.Logger;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.TextWebSocketHandler;


public class SpringWebSocketHandler extends TextWebSocketHandler {
    private static final ArrayList users;//这个会出现性能问题，最好用Map来存储，key用userid
    private static Logger logger = Logger.getLogger(SpringWebSocketHandler.class);
    static {
        users = new ArrayList();
    }
    
    public SpringWebSocketHandler() {
        // TODO Auto-generated constructor stub
    }

    /**
     * 连接成功时候，会触发页面上onopen方法
     */
    public void afterConnectionEstablished(WebSocketSession session) throws Exception {
        // TODO Auto-generated method stub
        System.out.println("connect to the websocket success......当前数量:"+users.size());
        users.add(session);
        //这块会实现自己业务，比如，当用户登录后，会把离线消息推送给用户
        //TextMessage returnMessage = new TextMessage("你将收到的离线");
        //session.sendMessage(returnMessage);
    }
    
    /**
     * 关闭连接时触发
     */
    public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
        logger.debug("websocket connection closed......");
        String username= (String) session.getAttributes().get("WEBSOCKET_USERNAME");
        System.out.println("用户"+username+"已退出！");
        users.remove(session);
        System.out.println("剩余在线用户"+users.size());
    }

    /**
     * js调用websocket.send时候，会调用该方法
     */
    @Override    
    protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
        super.handleTextMessage(session, message);
    }

    public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
        if(session.isOpen()){session.close();}
        logger.debug("websocket connection closed......");
        users.remove(session);
    }

    public boolean supportsPartialMessages() {
        return false;
    }
    
    
    /**
     * 给某个用户发送消息
     *
     * @param userName
     * @param message
     */
    public void sendMessageToUser(String userName, TextMessage message) {
        for (WebSocketSession user : users) {
            if (user.getAttributes().get("WEBSOCKET_USERNAME").equals(userName)) {
                try {
                    if (user.isOpen()) {
                        user.sendMessage(message);
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
                break;
            }
        }
    }
    
    /**
     * 给所有在线用户发送消息
     *
     * @param message
     */
    public void sendMessageToUsers(TextMessage message) {
        for (WebSocketSession user : users) {
            try {
                if (user.isOpen()) {
                    user.sendMessage(message);
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

}

 

第四步：继承HttpSessionHandshakeInterceptor对象。该对象作为页面连接websocket服务的拦截器,代码如下：

package com.quicksand.push;
import java.util.Map;

import javax.servlet.http.HttpSession;

import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.http.server.ServletServerHttpRequest;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.support.HttpSessionHandshakeInterceptor;

/**
 * WebSocket拦截器
 * @author WANG
 *
 */
public class SpringWebSocketHandlerInterceptor extends HttpSessionHandshakeInterceptor {
    @Override
    public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
            Map attributes) throws Exception {
        // TODO Auto-generated method stub
        System.out.println("Before Handshake");
        if (request instanceof ServletServerHttpRequest) {
            ServletServerHttpRequest servletRequest = (ServletServerHttpRequest) request;
            HttpSession session = servletRequest.getServletRequest().getSession(false);
            if (session != null) {
                //使用userName区分WebSocketHandler，以便定向发送消息
                String userName = (String) session.getAttribute("SESSION_USERNAME");
                if (userName==null) {
                    userName="default-system";
                }
                attributes.put("WEBSOCKET_USERNAME",userName);
            }
        }
        return super.beforeHandshake(request, response, wsHandler, attributes);
        
    }
    
    @Override
    public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
            Exception ex) {
        // TODO Auto-generated method stub
        super.afterHandshake(request, response, wsHandler, ex);
    }
}

 

第5步 让SpringWebSocketConfig配置类随spring容器启动 spring文件中加入如下代码：