来源:https://blog.csdn.net/qq_35515521/article/details/78610847
定义:
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——允许服务器主动发送信息给客户端
上面是百度官网的介绍,我主要使用websocket的目的是为了,能让服务器能够主动推送消息给浏览器,而不是之前通过ajax或者长轮循不断触发服务器。
我通过学习整合了一个简单可用通讯的实例。好了,废话不多说,直接上内容。
整合步骤:
由于我用的maven项目,所以先通过pom.xml进行引包。
**第一步:**pom.xml引包
在这里需要注意2点:1、spring相关的jar包必须是版本4以上的 2、websoket引入的jar包版本号和spring的版本号要一直,如果不一致的话回出现:NoClassDefFoundError: org/springframework/web/cors/CorsProcessor,这样框架异常。
添加的spring的支持包:
<!-- 添加Spring支持 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-core</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-beans</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-tx</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-context-support</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-web</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aop</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>commons-lang</groupId>
<artifactId>commons-lang</artifactId>
<version>2.6</version>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-aspects</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-jdbc</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
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添加websocket的jar包
<!-- 添加对websocket的支持 -->
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-orm</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-webmvc</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-websocket</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
<dependency>
<groupId>org.springframework</groupId>
<artifactId>spring-messaging</artifactId>
<version>4.2.4.RELEASE</version>
</dependency>
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第二步:配置spring-websocket.xml文件
这里注意的是:xsi:schemaLocation属性后面俩行一定要有。
<?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: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">
<bean id="websocket" class="com.web.common.util.websocket.WebSocketHander" />
<websocket:handlers>
<websocket:mapping path="/echo" handler="websocket" />
<websocket:handshake-interceptors>
<bean class="com.web.common.util.websocket.HandshakeInterceptor" />
</websocket:handshake-interceptors>
</websocket:handlers>
</beans>
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在applicationContext.xml中引入spring-websocket.xml文件
<!-- 引入websocket -->
<import resource="spring-websocket.xml"/>
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在web.xml中引入applicationContext.xml
<!-- Spring配置文件 -->
<context-param>
<param-name>contextConfigLocation</param-name>
<param-value>classpath:applicationContext.xml</param-value>
</context-param>
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第三步:编写代码
package com.web.common.util.websocket;
import org.apache.shiro.session.Session;
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 javax.servlet.http.HttpServletRequest;
import java.util.Map;
/**
* 拦截器
*
* @author wangguan,
* @date 2017年11月22日 上午9:33:46,
* @version argType
*/
public class HandshakeInterceptor implements org.springframework.web.socket.server.HandshakeInterceptor{
Session session;
// 初次握手访问前
public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse serverHttpResponse,
WebSocketHandler webSocketHandler, Map<String, Object> map) throws Exception {
if (request instanceof ServletServerHttpRequest) {
HttpServletRequest servletRequest = ((ServletServerHttpRequest) request).getServletRequest();
String sessionId=servletRequest.getSession().getId();//获取浏览器的sessionid
String username=(String)servletRequest.getSession().getAttribute("name");
System.out.println("获取session里面的name-------------------"+username);
// 使用userName区分WebSocketHandler,以便定向发送消息
/* String userName = (String)*/
//session.getAttribute("WEBSOCKET_USERNAME");
map.put("WEBSOCKET_USERNAME", username);
servletRequest.getSession().setAttribute("WEBSOCKET_USERNAME", username);
}
return true;
}
// 初次握手访问后
public void afterHandshake(ServerHttpRequest serverHttpRequest, ServerHttpResponse serverHttpResponse,
WebSocketHandler webSocketHandler, Exception e) {
}
}
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WebSocketHander 实现WebSocketHandler
package com.web.common.util.websocket;
import org.apache.log4j.Logger;
import org.springframework.web.socket.*;
import java.io.IOException;
import java.util.ArrayList;
public class WebSocketHander implements WebSocketHandler {
private static final Logger logger = Logger.getLogger(WebSocketHander.class);
private static final ArrayList<WebSocketSession> users = new ArrayList<WebSocketSession>();
private String userName="";
// 初次链接成功执行
public void afterConnectionEstablished(WebSocketSession session) throws Exception {
logger.debug("链接成功......");
users.add(session);
userName = (String) session.getAttributes().get("WEBSOCKET_USERNAME");
System.out.println("第一次连接获取的id--"+userName);
if (userName != null) {
// 查询未读消息
int count = 5;
session.sendMessage(new TextMessage(count + ""));
}
}
// 接受消息处理消息
public void handleMessage(WebSocketSession webSocketSession, WebSocketMessage<?> webSocketMessage)
throws Exception {
//sendMessageToUsers(new TextMessage(webSocketMessage.getPayload() + ""));
sendMessageToUser(userName, new TextMessage(webSocketMessage.getPayload() + ""));
}
public void handleTransportError(WebSocketSession webSocketSession, Throwable throwable) throws Exception {
if (webSocketSession.isOpen()) {
webSocketSession.close();
}
logger.debug("链接出错,关闭链接......");
users.remove(webSocketSession);
}
public void afterConnectionClosed(WebSocketSession webSocketSession, CloseStatus closeStatus) throws Exception {
logger.debug("链接关闭......" + closeStatus.toString());
users.remove(webSocketSession);
}
public boolean supportsPartialMessages() {
return false;
}
/**
* 给所有在线用户发送消息
*
* @param message
*/
public void sendMessageToUsers(TextMessage message) {
for (WebSocketSession user : users) {
System.out.println(user.getAttributes().get("WEBSOCKET_USERNAME"));
try {
if (user.isOpen()) {
user.sendMessage(message);
}
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 给某个用户发送消息,模拟给admin发信息
*
* @param userName
* @param message
*/
public void sendMessageToUser(String userName, TextMessage message) {
for (WebSocketSession user : users) {
System.out.println("从session里面获取的id"+user.getAttributes().get("WEBSOCKET_USERNAME"));
if (user.getAttributes().get("WEBSOCKET_USERNAME").equals("admin")) {
try {
if (user.isOpen()) {
user.sendMessage(message);
}
} catch (IOException e) {
e.printStackTrace();
}
break;
}
}
}
}
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启动项目:
我做了一个模拟,用俩个用户登录,让其中一个用户发消息,另外一个用户接受到消息。所以在我HandshakeInterceptor 用session去用户的登录名用户定向发送消息。(可以自己写一个login的controller,然后把loginName存入的session中,这样HandshakeInterceptor 中才能取到name值。)
我分别用360浏览器和火狐浏览器,模拟俩个登录用户,admin和tea
由tea向admin发送消息