maven依赖
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-websocket</artifactId>
<version>4.0.3.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-messaging</artifactId>
<version>4.3.2.RELEASE</version>
</dependency>
<dependency>
<groupId>javax.websocket</groupId>
<artifactId>javax.websocket-api</artifactId>
<version>1.0</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.eclipse.jetty.websocket</groupId>
<artifactId>websocket-server</artifactId>
<version>9.3.3.v20150827</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.tomcat.embed</groupId>
<artifactId>tomcat-embed-websocket</artifactId>
<version>8.0.23</version>
<scope>provided</scope>
</dependency>
配置入口类
配置WebSocket的入口,编写WebSocketConfig类实现WebSocketConfigurer 接口
package com.hiwei.demo.webSocket;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
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
@EnableWebSocket
@EnableWebMvc
public class SpringWebSocketConfig implements WebSocketConfigurer {
@Override
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();
}
}
定义入口类
定义一个SpringWebSocketHandler类继承TextWebSocketHandler，这个类是用来处理Websocket连接建立、断开，消息发送的逻辑的，这个是消息处理的核心代码:
package com.hiwei.demo.webSocket;
import java.io.IOException;
import java.util.HashMap;
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 HashMap<String,WebSocketSession> users;
static {
users = new HashMap<String,WebSocketSession>();
}
public SpringWebSocketHandler() {
}
/**
* 连接成功触发
*/
@Override
public void afterConnectionEstablished(WebSocketSession session) throws Exception {
users.put((String) session.getAttributes().get("SESSION_USERID"), session);
System.out.println("connect to the websocket success......当前数量:"+users.size());
//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("连接成功");
session.sendMessage(returnMessage);
}
/**
* 关闭连接时触发
*/
@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
String username= (String) session.getAttributes().get("WEBSOCKET_USERNAME");
System.out.println("用户"+username+"已退出！");
users.remove(session.getAttributes().get("SESSION_USERID"));
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);
TextMessage returnMessage = new TextMessage(message.getPayload().toString());
sendMessageToUsers(returnMessage);
}
public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
if(session.isOpen()){session.close();}
users.remove(session.getAttributes().get("SESSION_USERID"));
}
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.values()) {
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.values()) {
try {
if (user.isOpen()) {
user.sendMessage(message);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
拦截器配置
从WebSocketConfig中可以看到在注册WebSocket通道时，不仅设置了入口地址，还配置了拦截器，拦截器可以实现握手之前和之后的逻辑操作，这里配置的拦截器主要用于保存用户名以便于在Handler中定向发送消息。
package com.hiwei.demo.webSocket;
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;
public class SpringWebSocketHandlerInterceptor extends HttpSessionHandshakeInterceptor {
@Override
public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler,
Map<String, Object> attributes) throws Exception {
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) {
super.afterHandshake(request, response, wsHandler, ex);
}
}
配置Websocket连接前台页面
网页端连接Websocket和推送消息的界面就是这里
<%@ page language="java" contentType="text/html; charset=utf-8"
pageEncoding="utf-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>消息</title>
</head>
<body>
<script type="text/javascript" src="http://cdn.bootcss.com/jquery/3.1.0/jquery.min.js"></script>
<script type="text/javascript" src="http://cdn.bootcss.com/sockjs-client/1.1.1/sockjs.js"></script>
<script type="text/javascript">
var msgDiv = document.getElementById("#msgDiv");
var websocket = null;
if ('WebSocket' in window) {
websocket = new WebSocket("ws://172.30.99.37:8080/springmvcMybatis/websocket/socketServer.do");
}
else if ('MozWebSocket' in window) {
websocket = new MozWebSocket("ws://172.30.99.37:8080/springmvcMybatis/websocket/socketServer.do");
}
else {
websocket = new SockJS("http://172.30.99.37:8080/springmvcMybatis/sockjs/socketServer.do");
}
websocket.onopen = onOpen;
websocket.onmessage = onMessage;
websocket.onerror = onError;
websocket.onclose = onClose;
function onOpen(openEvt) {
//alert(openEvt.Data+"onOpen");
}
function onMessage(evt) {
$('#msgDiv').val(evt.data)
}
function onError() {
alert("出错"+"onError");
}
function onClose() {
alert("关闭"+"onClose");
}
function doSend() {
if (websocket.readyState == websocket.OPEN) {
var msg = document.getElementById("inputMsg").value;
websocket.send(msg);
} else {
alert("连接失败!");
}
}
window.close=function(){
websocket.onclose();
}
</script>
<body align="center">
<h3>消息推送</h3>
请输入：<textarea rows="8" cols="50" id="inputMsg" name="inputMsg"></textarea>
<button onclick="doSend();">发送</button>
<hr/>
<textarea rows="10" cols="70" id="msgDiv"></textarea>
</body>
</html>
另：web.xml中的servlet和filter中添加异步支持
<async-supported>true</async-supported>