Spring MVC 自学杂记（四） -- Spring+SpringMVC+WebSocket
1、WebSocket简介
WebSocket是HTML5提供的一种全双工通信的协议，通常是浏览器（或其他客户端）与Web服务器之间的通信。这使得它适合于高度交互的Web应用程序，如及时通讯聊天等。
WebSocket协议是基于TCP的一种新的网络协议。它实现了浏览器与服务器全双工(full-duplex)通信——可以通俗的解释为服务器主动发送信息给客户端。
WebSocket首次在HTML5规范中被引用为TCP连接，作为基于TCP的套接字API的占位符。[1] WebSocket通信协议于2011年被IETF定为标准RFC 6455，并被RFC7936所补充规范。
摘抄来自：百度百科-websocket
2、Spring+websocket
spring4.0已经就支持websocket了，可以去查看官网。
官网：spring websocket
注：这个spring+websocket，自己也不是很熟悉，只是最近使用到了，学习了一下，记录处理了，方便以后避免走更多的绕路。
3、配置环境
3.1、环境：
spring-4.0.2.RELEASE
java1.7
apache-tomcat-7.0.75
maven构建工程：
POM.xml：
<dependency>
<groupId>com.fasterxml.jackson.coregroupId>
<artifactId>jackson-coreartifactId>
<version>2.3.0version>
dependency>
<dependency>
<groupId>com.fasterxml.jackson.coregroupId>
<artifactId>jackson-databindartifactId>
<version>2.3.0version>
dependency>
SpringMVC：
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-webmvcartifactId>
<version>4.0.2.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-context-supportartifactId>
<version>4.0.2.RELEASEversion>
dependency>
WebSocket：
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-websocketartifactId>
<version>4.0.2.RELEASEversion>
dependency>
<dependency>
<groupId>org.springframeworkgroupId>
<artifactId>spring-messagingartifactId>
<version>4.0.2.RELEASEversion>
dependency>
3.2、Servlet-api
servlet-api必须是3.0+，才支持websocket，所以如果不是，则要更新jar包。
<dependency>
<groupId>javax.servletgroupId>
<artifactId>javax.servlet-apiartifactId>
<version>3.1.0version>
dependency>
3.3、web.xml配置
并且 web.xml的namespace也要确保是3.0+，
web.xml
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"
version="3.0">
<absolute-ordering />
web-app>
代码：
并且必须将所以的filter和servlet都要添加异步：
<async-supported>trueasync-supported>
如：springMVC在web.xml中的配置也要添加：
<servlet>
<servlet-name>springMVCservlet-name>
<servlet-class>org.springframework.web.servlet.DispatcherServletservlet-class>
<init-param>
<param-name>contextConfigLocationparam-name>
<param-value>classpath:springMVC.xmlparam-value>
init-param>
<load-on-startup>1load-on-startup>
<async-supported>trueasync-supported>
servlet>
<servlet-mapping>
<servlet-name>springMVCservlet-name>
<url-pattern>/url-pattern>
servlet-mapping>
4、service服务端的具体实现
4.1、首先创建websocket的处理类
MyWebSocketHandler.java
package com.cuit.secims.mw.ws;
import java.util.ArrayList;
import java.util.Map;
import org.apache.log4j.Logger;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.WebSocketMessage;
import org.springframework.web.socket.WebSocketSession;
import com.google.common.reflect.TypeToken;
import com.google.gson.Gson;
public class MyWebSocketHandler implements WebSocketHandler{
private static final Logger log = Logger.getLogger(MyWebSocketHandler.class);
// 保存所有的用户session
private static final ArrayList<WebSocketSession> users = new ArrayList<WebSocketSession>();
// 连接 就绪时
@Override
public void afterConnectionEstablished(WebSocketSession session)
throws Exception {
log.info("connect websocket success.......");
users.add(session);
}
// 处理信息
@Override
public void handleMessage(WebSocketSession session,
WebSocketMessage<?> message) throws Exception {
Gson gson = new Gson();
// 将消息JSON格式通过Gson转换成Map
// message.getPayload().toString() 获取消息具体内容
Map<String, Object> msg = gson.fromJson(message.getPayload().toString(),
new TypeToken<Map<String, Object>>() {
}.getType());
log.info("handleMessage......."+message.getPayload()+"..........."+msg);
// session.sendMessage(message);
// 处理消息 msgContent消息内容
TextMessage textMessage = new TextMessage(msg.get("msgContent").toString(), true);
// 调用方法（发送消息给所有人）
sendMsgToAllUsers(textMessage);
}
// 处理传输时异常
@Override
public void handleTransportError(WebSocketSession session,
Throwable exception) throws Exception {
// TODO Auto-generated method stub
}
// 关闭 连接时
@Override
public void afterConnectionClosed(WebSocketSession session,
CloseStatus closeStatus) throws Exception {
log.info("connect websocket closed.......");
users.remove(session);
}
@Override
public boolean supportsPartialMessages() {
// TODO Auto-generated method stub
return false;
}
// 给所有用户发送 信息
public void sendMsgToAllUsers(WebSocketMessage<?> message) throws Exception{
for (WebSocketSession user : users) {
user.sendMessage(message);
}
}
}
处理类可以实现WebSocketHandler最基本的接口，也可以实现具体的接口
如：
处理类就是处理：连接开始、关闭、处理信息等方法
4.2、创建握手（handshake）接口/拦截器
HandshakeInterceptor .java
package com.cuit.secims.mw.ws;
import java.util.Map;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.support.HttpSessionHandshakeInterceptor;
public class HandshakeInterceptor extends HttpSessionHandshakeInterceptor{
// 握手前
@Override
public boolean beforeHandshake(ServerHttpRequest request,
ServerHttpResponse response, WebSocketHandler wsHandler,
Map attributes) throws Exception {
System.out.println("++++++++++++++++ HandshakeInterceptor: beforeHandshake ++++++++++++++"+attributes);
return super.beforeHandshake(request, response, wsHandler, attributes);
}
// 握手后
@Override
public void afterHandshake(ServerHttpRequest request,
ServerHttpResponse response, WebSocketHandler wsHandler,
Exception ex) {
System.out.println("++++++++++++++++ HandshakeInterceptor: afterHandshake ++++++++++++++");
super.afterHandshake(request, response, wsHandler, ex);
}
}
这个的主要作用是可以在握手前做一些事，把所需要的东西放入到attributes里面，然后可以在WebSocketHandler的session中， 取到相应的值，具体可参考HttpSessionHandshakeInterceptor，这儿也可以实现HandshakeInterceptor 接口。
4.3、注册处理类及握手接口
这个有两种方式：
- 创建一个类来实现注册
- 使用xml配置文件实现
4.3.1、创建类MyWebSocketConfig
package com.cuit.secims.mw.ws;
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.WebSocketHandler;
import org.springframework.web.socket.config.annotation.EnableWebSocket;
import org.springframework.web.socket.config.annotation.WebSocketConfigurer;
import org.springframework.web.socket.config.annotation.WebSocketHandlerRegistry;
@Configuration
@EnableWebMvc
@EnableWebSocket
public class MyWebSocketConfig extends WebMvcConfigurerAdapter implements WebSocketConfigurer {
@Override
public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
//前台 可以使用websocket环境
registry.addHandler(myWebSocketHandler(),"/websocket").addInterceptors(new HandshakeInterceptor());
//前台 不可以使用websocket环境，则使用sockjs进行模拟连接
registry.addHandler(myWebSocketHandler(), "/sockjs/websocket").addInterceptors(new HandshakeInterceptor())
.withSockJS();
}
// websocket 处理类
@Bean
public WebSocketHandler myWebSocketHandler(){
return new MyWebSocketHandler();
}
}
注意：不要忘记在springmvc的配置文件中配置对此类的自动扫描
4.3.2、xml配置方式
spring-WebSocket.xml
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:mvc="http://www.springframework.org/schema/mvc"
xmlns:context="http://www.springframework.org/schema/context"
xmlns:aop="http://www.springframework.org/schema/aop"
xmlns:tx="http://www.springframework.org/schema/tx"
xmlns:websocket="http://www.springframework.org/schema/websocket"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/mvc
http://www.springframework.org/schema/mvc/spring-mvc-4.0.xsd
http://www.springframework.org/schema/context
http://www.springframework.org/schema/context/spring-context-4.0.xsd
http://www.springframework.org/schema/aop
http://www.springframework.org/schema/aop/spring-aop-4.0.xsd
http://www.springframework.org/schema/tx
http://www.springframework.org/schema/tx/spring-tx-4.0.xsd
http://www.springframework.org/schema/websocket
http://www.springframework.org/schema/websocket/spring-websocket-4.0.xsd">
<bean id="myHandler" class="com.cuit.secims.mw.ws.MyWebSocketHandler"/>
<bean id="myInterceptor" class="com.cuit.secims.mw.ws.HandshakeInterceptor"/>
<websocket:handlers >
<websocket:mapping path="/websocket" handler="myHandler"/>
<websocket:handshake-interceptors>
<ref bean="myInterceptor"/>
websocket:handshake-interceptors>
websocket:handlers>
<websocket:handlers>
<websocket:mapping path="/sockjs/websocket" handler="myHandler"/>
<websocket:handshake-interceptors>
<ref bean="myInterceptor"/>
websocket:handshake-interceptors>
<websocket:sockjs />
websocket:handlers>
beans>
其中
注意：xml的namespace中要添加spring对websocket的支持：
<beans xmlns="http://www.springframework.org/schema/beans"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xmlns:websocket="http://www.springframework.org/schema/websocket"
xsi:schemaLocation="
http://www.springframework.org/schema/beans
http://www.springframework.org/schema/beans/spring-beans-4.0.xsd
http://www.springframework.org/schema/websocket
http://www.springframework.org/schema/websocket/spring-websocket-4.0.xsd">
5、client客户端的实现
5.1、页面展示
index.html
首页
5.2、JS-客户端主要的实现
index.js
$(function() {
var websocket;
// 首先判断是否 支持 WebSocket
if('WebSocket' in window) {
websocket = new WebSocket("ws://localhost:8080/SECIMS/websocket");
} else if('MozWebSocket' in window) {
websocket = new MozWebSocket("ws://localhost:8080/SECIMS/websocket");
} else {
websocket = new SockJS("http://localhost:8080/SECIMS/sockjs/websocket");
}
// 打开时
websocket.onopen = function(evnt) {
console.log(" websocket.onopen ");
};
// 处理消息时
websocket.onmessage = function(evnt) {
$("#msg").append("("
+ evnt.data + ")");
console.log(" websocket.onmessage ");
};
websocket.onerror = function(evnt) {
console.log(" websocket.onerror ");
};
websocket.onclose = function(evnt) {
console.log(" websocket.onclose ");
};
// 点击了发送消息按钮的响应事件
$("#TXBTN").click(function(){
// 获取消息内容
var text = $("#tx").val();
// 判断
if(text == null || text == ""){
alert(" content can not empty!!");
return false;
}
var msg = {
msgContent: text,
postsId: 1
};
// 发送消息
websocket.send(JSON.stringify(msg));
});
});
客户端的主要API就是 创建websocket、监听打开、关闭、发送信息、处理信息等方法。
websocket = new WebSocket("ws://localhost:8080/SECIMS/websocket");
如果环境不支持websocket，则使用sockJS来模拟连接实现
websocket = new SockJS("http://localhost:8080/SECIMS/sockjs/websocket");
其中：SECIMS是工程名，而/websocket是环境支持，则请求的连接。而/sockjs/websocket，则是不支持websocket，使用sockJS模拟实现的连接。
6、效果展现
用户A：
用户B：
7、项目地址
项目GIT地址: https://gitee.com/tianwyam/SpringMVC_WebSocket.git
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