（java）websocket服务的两种实现方式

1.基于java注解实现websocket服务器端

1.1需要的类

1.1.1服务终端类

用java注解来监听连接@ServerEndpoint、连接成功@OnOpen、连接失败@OnClose、收到消息等状态@OnMessage

1.1.2配置类

把spring中的ServerEndpointExporter对象注入进来

2.1代码示例

2.1.1 maven配置

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.heima</groupId>
    <artifactId>ws-demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>8</maven.compiler.source>
        <maven.compiler.target>8</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>
    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
           <version>2.7.3</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.22</version>
        </dependency>
        <!-- https://mvnrepository.com/artifact/org.springframework.boot/spring-boot-starter-websocket -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-websocket</artifactId>
            <version>2.7.14</version>
        </dependency>



    </dependencies>

</project>

2.1.2 WsServerEndpoint类

package com.heima;

import lombok.extern.slf4j.Slf4j;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;

import javax.websocket.OnClose;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

/***
 * 监听websocket地址  /myWs
 */
@ServerEndpoint("/myWs")
@Component
@Slf4j
@EnableScheduling
public class WsServerEndpoint {

    static Map<String,Session> map = new ConcurrentHashMap<String,Session>();

    /***
     * 连接建立时执行的操作
     * @param session
     */
    @OnOpen
    public void onOpen(Session session)
    {
        map.put(session.getId(),session);
        log.info("websocket is open");
    }

    /***
     * 收到客户端消息执行的操作
     * @param text
     */
    @OnMessage
    public String OnMessage(String text)
    {
        log.info("收到了一条信息"+text);
        return "已收到你的信息" ;
    }

    /***
     * 连接关闭时执行的操作
     * @param session
     */
    @OnClose
    public void OnClose(Session session)
    {
        map.remove(session.getId());
        log.info("连接关闭时执行的操作");
    }

    /***
     * 向客户端发送信息
     */
    @Scheduled(fixedRate = 2000)
    public void sendMsg() throws IOException {
        for (String key : map.keySet())
        {
            map.get(key).getBasicRemote().sendText("你好，你好");
        }
    }
}

2.1.3 WebSocketConfig

package com.heima;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.socket.server.standard.ServerEndpointExporter;

@Configuration
public class WebSocketConfig {


    @Bean
 public ServerEndpointExporter serverEndpointExporter()
 {
     return new ServerEndpointExporter();
 }



}

2.1.3 前端测试代码

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>wsClient</title>
</head>
<body>

<script>
     // 创建websocket
    let ws = new WebSocket("ws://localhost:8080/myWs")
     //向服务器发送hello
    ws.onopen=function (){
        ws.send("hello")
    }
    //监听数据ws://localhost:8080/myWs
    ws.onmessage=function (message){
        console.log(message.data)
    }
</script>
</body>
</html>

2.1.4测试结果

2.1.4.1 当打开浏览器时

2.1.4.2 当关闭浏览器时

2.1.4.3 当刷新浏览器的时候

2.基于spring提供的类和接口刷新websocket服务器端

2.1：HttpSessionHandShakeInter 握手拦截器

package com.spring;

import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Configuration;
import org.springframework.http.server.ServerHttpRequest;
import org.springframework.http.server.ServerHttpResponse;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.WebSocketHandler;
import org.springframework.web.socket.server.support.HttpSessionHandshakeInterceptor;

import java.util.Map;

/***
 * 握手拦截器
 */
@Component
@Slf4j
public class MyWsInterceptor extends HttpSessionHandshakeInterceptor {


    @Override
    public boolean beforeHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Map<String, Object> attributes) throws Exception {
        log.info(request.getRemoteAddress().toString()+"开始握手");
        return super.beforeHandshake(request, response, wsHandler, attributes);
    }

    @Override
    public void afterHandshake(ServerHttpRequest request, ServerHttpResponse response, WebSocketHandler wsHandler, Exception ex) {
         log.info(request.getRemoteAddress().toString()+"完成握手");
        super.afterHandshake(request, response, wsHandler, ex);
    }
}

2.2 MyWsHandler 主处理程序

sessionbean封装类

import lombok.AllArgsConstructor;
import lombok.Data;
import org.springframework.web.socket.WebSocketSession;

@Data
@AllArgsConstructor
public class SessionBean {
    private WebSocketSession webSocketSession;
    private Integer clientId;
}

主处理程序

package com.spring;

import lombok.extern.slf4j.Slf4j;
import org.springframework.boot.web.servlet.server.Session;
import org.springframework.scheduling.annotation.EnableScheduling;
import org.springframework.scheduling.annotation.Scheduled;
import org.springframework.stereotype.Component;
import org.springframework.web.socket.CloseStatus;
import org.springframework.web.socket.TextMessage;
import org.springframework.web.socket.WebSocketSession;
import org.springframework.web.socket.handler.AbstractWebSocketHandler;

import java.io.IOException;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;
import java.util.concurrent.atomic.AtomicInteger;

/***
 * webSocket 主处理程序
 */
@Component
@Slf4j
@EnableScheduling
public class MyWsHandler extends AbstractWebSocketHandler {
    //map有并发线程问题  所以用ConcurrentHashMap
    private static Map<String, SessionBean> map ;
    //id有并发问题 所以用Integer的安全类型
    private static AtomicInteger clientIdMaker;
    static {

        map = new ConcurrentHashMap<>();
        clientIdMaker=new AtomicInteger(0);
    }
    //连接建立
    @Override
    public void afterConnectionEstablished(WebSocketSession session) throws Exception {
        super.afterConnectionEstablished(session);
        //将session 进一步封装  id采用的是自增
        SessionBean sessionBean = new SessionBean(session, clientIdMaker.getAndIncrement());
        map.put(session.getId(),sessionBean);
        log.info(map.get(session.getId()).getClientId()+"建立了连接");
    }

    //收到消息
    @Override
    protected void handleTextMessage(WebSocketSession session, TextMessage message) throws Exception {
        super.handleTextMessage(session, message);
        log.info(map.get(session.getId()).getClientId()+":"+message.getPayload());
    }

    //传输异常
    @Override
    public void handleTransportError(WebSocketSession session, Throwable exception) throws Exception {
        super.handleTransportError(session, exception);

        if (session.isOpen())
        {
            session.close();
        }
        map.remove(session.getId());

    }
    //连接关闭
    @Override
    public void afterConnectionClosed(WebSocketSession session, CloseStatus status) throws Exception {
        super.afterConnectionClosed(session, status);
        log.info(map.get(session.getId()).getClientId()+"关闭连接");
    }

    /***
     * 向客户端发送信息
     */
    @Scheduled(fixedRate = 2000)
    public void sendMsg() throws IOException {
        for (String key : map.keySet())
        {
            map.get(key).getWebSocketSession().sendMessage(new TextMessage("hello," +
                    "spring socket"));
        }
    }
}

2.3 WebSocketConfigurer 注册拦截器和主处理程序以及监听路径

package com.spring;

import org.springframework.context.annotation.Configuration;
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 javax.annotation.Resource;

@Configuration
@EnableWebSocket
public class MyWsConfig implements WebSocketConfigurer {
    @Resource
    private MyWsHandler wsHandler;
    @Resource
    private MyWsInterceptor wsInterceptor;
    @Override
    public void registerWebSocketHandlers(WebSocketHandlerRegistry registry) {
        registry.addHandler(wsHandler,"/myWs1").addInterceptors(wsInterceptor).setAllowedOriginPatterns("*");
    }
}

2.4 前端测试

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>wsClient</title>
</head>
<body>

<script>
     // 创建websocket
    let ws = new WebSocket("ws://localhost:8080/myWs1")
     //向服务器发送hello
    ws.onopen=function (){
        ws.send("hello")
    }
    //监听数据ws://localhost:8080/myWs
    ws.onmessage=function (message){
        console.log(message.data)
    }
</script>
</body>
</html>