WebSocket 学习教程（二）：Spring websocket实现消息推送
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环境介绍：
Jdk 1.7 （1.6不支持）
Tomcat7.0.52 （支持Websocket协议）
Spring4.0.26 （支持Websocket）
web.xml（配置了前端自动优化HtmlCompressor和Druid监控），自动优化会影响Websocket js脚本，后面会讲
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配置步骤：
1. 引入Spring相关Jar，特别需要下面这两个
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-websocket</artifactId>
<version>4.0.6.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-messaging</artifactId>
<version>4.0.6.RELEASE</version>
</dependency>
2. 编写WebSocketConfig implements WebSocketConfigurer
WebSocketConfig.java
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;
import cn.com.ship.message.handler.ChatMessageHandler;
import cn.com.ship.message.handler.TextMessageHandler;
@Configuration
//@EnableWebMvc//这个标注可以不加，如果有加，要extends WebMvcConfigurerAdapter
@EnableWebSocket
public class WebSocketConfig implements WebSocketConfigurer {
@Override
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
registry.addHandler(chatMessageHandler(),"/websocket/chatMessageServer.do").addInterceptors(new ChatHandshakeInterceptor());
registry.addHandler(chatMessageHandler(), "/sockjs/chatMessageServer.do").addInterceptors(new ChatHandshakeInterceptor()).withSockJS();
}
@Bean
public TextWebSocketHandler chatMessageHandler(){
return new ChatMessageHandler();
}
}
3. 编写ChatMessageHandler extends TextWebSocketHandler
ChatMessageHandler.java
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;
import cn.com.ship.message.common.Constants;
import cn.com.ship.message.common.MessageCriteria;
public class ChatMessageHandler extends TextWebSocketHandler{
private static final ArrayList<WebSocketSession> 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(ChatMessageHandler.class);
static {
users = new ArrayList<WebSocketSession>();
}
public ChatMessageHandler() {
// TODO Auto-generated constructor stub
}
/**
* 连接成功时候，会触发UI上onopen方法
*/
@Override
public void afterConnectionEstablished(WebSocketSession session) throws Exception {
System.out.println("connect to the websocket success......");
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);
}
/**
* 在UI在用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);
}
/**
* 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(Constants.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();
}
}
}
@Override
public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
if(session.isOpen()){
session.close();
}
logger.debug("websocket connection closed......");
users.remove(session);
}
@Override
public void afterConnectionClosed(WebSocketSession session, CloseStatus closeStatus) throws Exception {
logger.debug("websocket connection closed......");
users.remove(session);
}
@Override
public boolean supportsPartialMessages() {
return false;
}
}
4. 编写websocket握手拦截器ChatHandshakeInterceptor extends HttpSessionHandshakeInterceptor
ChatHandshakeInterceptor.java
package cn.com.ship.message.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;
import cn.com.ship.message.common.Constants;
public class ChatHandshakeInterceptor extends HttpSessionHandshakeInterceptor {
@Override
public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object> attributes) throws Exception {
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(Constants.SESSION_USERNAME);
if (userName==null) {
userName="default-system";
}
attributes.put(Constants.WEBSOCKET_USERNAME,userName);
}
}
return super.beforeHandshake(request, response, wsHandler, attributes);
}
@Override
public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Exception ex) {
System.out.println("After Handshake");
super.afterHandshake(request, response, wsHandler, ex);
}
}
4. 重点在Spring mvc相关配置（经常出现问题就是：中文乱码，如果是用ajax交互）
<?xml version="1.0" encoding="UTF-8"?> <beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:jee="http://www.springframework.org/schema/jee" xmlns:tx="http://www.springframework.org/schema/tx" xmlns:aop="http://www.springframework.org/schema/aop" xmlns:p="http://www.springframework.org/schema/p" xmlns:util="http://www.springframework.org/schema/util" xmlns:tool="http://www.springframework.org/schema/tool" xmlns:context="http://www.springframework.org/schema/context" xmlns:task="http://www.springframework.org/schema/task" xmlns:mvc="http://www.springframework.org/schema/mvc" xmlns:websocket="http://www.springframework.org/schema/websocket" xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx.xsd http://www.springframework.org/schema/aop http://www.springframework.org/schema/aop/spring-aop.xsd http://www.springframework.org/schema/jee http://www.springframework.org/schema/jee/spring-jee.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util.xsd http://www.springframework.org/schema/tool http://www.springframework.org/schema/tool/spring-tool.xsd http://www.springframework.org/schema/task http://www.springframework.org/schema/task/spring-task.xsd http://www.springframework.org/schema/websocket http://www.springframework.org/schema/websocket/spring-websocket-4.1.xsd http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc-4.1.xsd"> <!-- 这个bean要放在context:component-scan这个前面，不然会出现中文乱码 --> <bean class="org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter"> <property name="messageConverters"> <list> <ref bean="stringHttpMessageConverter" /> <ref bean="byteArrayHttpMessageConverter" /> <ref bean="jsonHttpMessageConverter" /> <ref bean="jsonHttpMessageConverter4JS" /> </list> </property> </bean> <!-- 启动SpringMVC Controller的注解功能，完成请求和注解POJO的映射 --> <context:component-scan base-package="cn.com.ship.*.**.controller" /> <!-- websocket相关扫描，主要扫描：WebSocketConfig.java 这个类路径 --> <context:component-scan base-package="cn.com.ship.message.websocket"/> <!-- 下面标签可以不加 等价于所有component-scan--> <context:annotation-config /> <!-- 这个重点，标注必须加，websocket用到--> <mvc:annotation-driven/> <bean id="byteArrayHttpMessageConverter" class="org.springframework.http.converter.ByteArrayHttpMessageConverter" /> <bean id="stringHttpMessageConverter" class="org.springframework.http.converter.StringHttpMessageConverter"> <property name="supportedMediaTypes"> <list> <value>text/plain;charset=UTF-8</value> </list> </property> </bean> <bean id="jsonHttpMessageConverter" class="cn.com.ship.external.spring.converter.json.MappingJackson2HttpMessageConverter"> <property name="objectMapper"> <bean class="com.fasterxml.jackson.databind.ObjectMapper"> <!--对属性值为null的不序列化反序列化--> <property name="serializationInclusion"> <util:constant static-field="com.fasterxml.jackson.annotation.JsonInclude.Include.NON_NULL"/> </property> </bean> </property> <property name="supportedMediaTypes"> <list> <value>application/json</value> </list> </property> </bean> <bean id="jsonHttpMessageConverter4JS" class="cn.com.ship.external.spring.converter.json.MappingJackson2HttpMessageConverter"> <property name="objectMapper"> <bean class="com.fasterxml.jackson.databind.ObjectMapper"> <property name="dateFormat"> <bean class="java.text.SimpleDateFormat"> <constructor-arg type="java.lang.String" value="yyyy-MM-dd HH:mm:ss" /> </bean> </property> <!--对属性值为null的不序列化反序列化--> <property name="serializationInclusion"> <util:constant static-field="com.fasterxml.jackson.annotation.JsonInclude.Include.NON_NULL"/> </property> </bean> </property> <property name="supportedMediaTypes"> <list> <value>text/json</value> </list> </property> </bean> <bean id="viewResolver" class="org.springframework.web.servlet.view.UrlBasedViewResolver"> <property name="viewClass" value="org.springframework.web.servlet.view.JstlView" /> <property name="prefix" value="/" /> <property name="suffix" value=".jsp" /> </bean> <!-- 文件上传配置 --> <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver" p:defaultEncoding="utf-8"> <property name="maxUploadSize" value="1024000000" /> <property name="resolveLazily" value="true" /> </bean> </beans>
注意：MappingJackson2HttpMessageConverter.java，来自Spring代码，并且修改了一点点，这个找到附件位置下载
5. jsp相关Websocket脚本编写
ws.jsp
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<html>
<head>
<title>Java API for WebSocket (JSR-356)</title>
</head>
<body>
<script type="text/javascript" src="http://localhost:8080/ship/js/jquery/jquery.min.js"></script>
<script type="text/javascript" src="http://localhost:8080/ship/js/sockjs-0.3.4.min.js"></script>
<script type="text/javascript">
var websocket = null;
if ('WebSocket' in window) {
websocket = new WebSocket("ws://localhost:8080/ship/webSocketServer.do");
}
else if ('MozWebSocket' in window) {
websocket = new MozWebSocket("ws://localhost:8080/ship/webSocketServer.do");
}
else {
websocket = new SockJS("http://localhost:8080/ship/sockjs/webSocketServer.do");
}
websocket.onopen = onOpen;
websocket.onmessage = onMessage;
websocket.onerror = onError;
websocket.onclose = onClose;
function onOpen(openEvt) {
//alert(openEvt.Data);
}
function onMessage(evt) {
alert(evt.data);
}
function onError() {}
function onClose() {}
function doSend() {
if (websocket.readyState == websocket.OPEN) {
var msg = document.getElementById("inputMsg").value;
websocket.send(msg);//调用后台handleTextMessage方法
alert("发送成功!");
} else {
alert("连接失败!");
}
}
</script>
请输入：<textarea rows="5" cols="10" id="inputMsg" name="inputMsg"></textarea>
<button onclick="doSend();">发送</button>
</body>
</html>
login.jsp
<%@ 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>Java API for WebSocket (JSR-356)</title>
</head>
<body>
<!-ship是我的项目名-->
<form action="/ship/websocket/login.do">
登录名：<input type="text" name="username"/>
<input type="submit" value="登录"/>
</form>
</body>
</html>
5. 调用端Controller编写 WebsocketController.java
package cn.com.ship.websocket.controller;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
@Controller
public class WebsocketController {
@Bean//这个注解会从Spring容器拿出Bean
public InfoHandler infoHandler() {
return new InfoHandler();
}
@RequestMapping("/websocket/login")
public void login(HttpServletRequest request, HttpServletResponse response) throws Exception {
String username = request.getParameter("username");
HttpSession session = request.getSession(false);
session.setAttribute(Constants.SESSION_USERNAME, username);
response.sendRedirect("/ship/websocket/ws.jsp");
}
@RequestMapping("/websocket/send")
@ResponseBody
public String send(HttpServletRequest request) {
String username = request.getParameter("username");
infoHandler().sendMessageToUser(username, new TextMessage("你好，测试！！！！"));
return null;
}
}
6. 测试Websocket是否连接成功
先在login.jsp上随便输入用户名，然后WebsocketController处理完请求，会重定向到ws.jsp
如果后台打印出现消息，证明Websocket连接成功（前两名消息是在ChatHandshakeInterceptor.java，最后一句是在ChatMessageHandler.java）
Before Handshake
After Handshake
connect to the websocket success......
