对话框

tcp socket套接字
http是单向传输协议：客户端->服务器，客户端request服务器response回去

websocket双工通信双向的
拉pull推push，http中做不了push（轮询，同源限制就是跨域）

1.加pom依赖，新建模块：spring-boot-websocker

11.png

1.1.加依赖：

   org.springframework.boot
   spring-boot-starter


   org.springframework.boot
   spring-boot-starter-websocket


   org.springframework.boot
   spring-boot-starter-test
   test


   org.projectlombok
   lombok
   1.18.6
   true


   com.spring4all
   swagger-spring-boot-starter
   1.8.0.RELEASE

• WebSocketConfig类

package com.springboot.websocker.config;

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

/**
 * WebSocket的配置类
 * 开启了WebSocket支持
 */
@Configuration
public class WebSocketConfig {

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

}

• WebSocketServer类

package com.springboot.websocker.config;

import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.CopyOnWriteArraySet;

//客户端向服务器端建立WebSocket连接的url
@ServerEndpoint("/websocket")
@Component
public class WebSocketServer {

    //静态变量，用来记录当前在线连接数,可选
    private static int onlineCount = 0;

    //concurrent包的线程安全Set，用来存放每个客户端对应的MyWebSocket对象，必须
    private static CopyOnWriteArraySet webSocketSet
            = new CopyOnWriteArraySet();

    //与某个客户端的连接会话，需要通过它来给客户端发送数据,必须
    private Session session;


    /**
     * 连接建立成功调用的方法
     */
    @OnOpen
    public void onOpen(Session session) {
        this.session = session;
        webSocketSet.add(this);     //将客户端加入set中
        addOnlineCount();           //在线数加1
        System.out.println("有新窗口开始监听,当前在线人数为"
                + getOnlineCount());
        try {
            sendMessage("连接成功");
        } catch (IOException e) {
            System.out.println("WebSocket IO异常");
        }
    }

    /**
     * 连接关闭调用的方法
     */
    @OnClose
    public void onClose() {
        webSocketSet.remove(this);  //从set中删除
        subOnlineCount();           //在线数减1
        System.out.println("有连接关闭！当前在线人数为" + getOnlineCount());
    }

    /**
     * 收到客户端消息后调用的方法
     *
     * @param message 客户端发送过来的消息
     */
    @OnMessage
    public void onMessage(String message, Session session) {
        System.out.println("收到客户端的信息:" + message);
        //群发消息
        for (WebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    /**
     * @param session
     * @param error
     */
    @OnError
    public void onError(Session session, Throwable error) {
        System.out.println("发生错误");
        error.printStackTrace();
    }

    /**
     * 实现服务器主动推送
     */
    public void sendMessage(String message) throws IOException {
        this.session.getBasicRemote().sendText(message);
    }


    /**
     * 群发自定义消息
     */
    public static void sendInfo(String message) throws IOException {
        System.out.println("推送消息内容:" + message);
        for (WebSocketServer item : webSocketSet) {
            try {
                item.sendMessage(message);
            } catch (IOException e) {
                continue;
            }
        }
    }

    public static synchronized int getOnlineCount() {
        return onlineCount;
    }

    public static synchronized void addOnlineCount() {
        WebSocketServer.onlineCount++;
    }

    public static synchronized void subOnlineCount() {
        WebSocketServer.onlineCount--;
    }
}

• WebSocketController类

package com.springboot.websocker.controller;


import com.springboot.websocker.config.WebSocketServer;
import org.springframework.web.bind.annotation.GetMapping;

import org.springframework.web.bind.annotation.RestController;

import java.io.IOException;

@RestController
public class WebSocketController {

    //推送数据接口
    @GetMapping("/socket/push")
    public String pushMsg(String message) {
        try {
            WebSocketServer.sendInfo(message);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return "success";
    }
}

底层统统不要捕获异常，所有的异常在controller捕获异常
create和onload只执行一次
前端代码：

    
        
        
        
        
        
        
        
        
        
    
    
        

            

                

                

                    
                    
                
            
            

                

                    
消息显示
                    

                        

                            {{message}}
                        
                    
                
            

            
            

                
                
                发送
            
            

                
                
                
                
                
            
        
        
    

watch监控元素是否发生变化