2021-10-30

1、开启WebSocket支持

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();
    }
}

import org.apache.commons.lang3.StringUtils;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Component;

import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.concurrent.atomic.AtomicInteger;


@Component
@ServerEndpoint(value = "/websocket/{userId}")
public class WebSocket {

    private Logger logger = LoggerFactory.getLogger(this.getClass());
    
    private AtomicInteger onlineNumber = new AtomicInteger(0);
    
    private Session session;
    
    private String userID;
    
    @onOpen
    public void onOpen(@PathParam("userId") String userId, Session session) {
      //把会话存到连接池中
      this.session=session;
      this.userID=userId;
      onlineNumber.incrementAndGet();
      System.out.println("有新连接加入！当前在线人数为" + onlineNumber.get() +" 当前session是" + session.hashCode()+" 用户id为： "+userId);
      SessionPool.sessions.put(userId,session);
    }

    @onError
    public void onError(Session session, Throwable error) {
        logger.info("服务端发生了错误"+error.getMessage());
        error.printStackTrace();
    }
    
    @onClose
    public void onClose(Session session) throws IOException {
        SessionPool.close(session.getId());
        session.close();
        System.out.println("websocket关闭成功!");
    }

    
    @onMessage
    public void onMessage(String message, Session session){
       try {
           if(StringUtils.isNotBlank(message)){
               //解析为JSON文件防止有个篡改
               System.out.println(message);
               
                 SessionPool.sendMessage("小和尚",message);
               }else {
                   logger.info("--用户不在线");
               }
       }catch (Exception e){
           e.printStackTrace();
       }
    }
}

import org.springframework.stereotype.Component;

import javax.websocket.Session;
import java.io.IOException;
import java.time.LocalDate;
import java.util.Map;
import java.util.concurrent.ConcurrentHashMap;

public class SessionPool {

    
    public static Map sessions = new ConcurrentHashMap();

    
    public static void close(String sessionId) throws IOException{
        for (String userID: sessions.keySet()) {
            Session session= sessions.get(userID);
            if(session.getId().equals(sessionId)){
                sessions.remove(userID);
                System.out.println(userID+"用户： "+LocalDate.now()+"  退出");
                break;
            }
        }
    }

    
    public static void sendMessage(String userId,String message){
        sessions.get(userId).getAsyncRemote().sendText(message);
    }

    
    public static void sendMessage(String message){
        for (String sessionId:SessionPool.sessions.keySet()){
            
            SessionPool.sessions.get(sessionId).getAsyncRemote().sendText(message);
        }
    }
}