1.首先新建模块：

<dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-websocket</artifactId>
</dependency>

• 或者在创建模块的时候按顺序点击添加：

  image

2.建立config、controller包：

image

3.WebSocketConfig、WebSocketServer、WebSocketController：

• WebSocketConfig

  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

  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<WebSocketServer> webSocketSet
        = new CopyOnWriteArraySet<WebSocketServer>();
  
      //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

  import com.soft1721.websocket.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";
      }
  }
  
  

4.接下来主方法WebsocketApplication

5.运行Swagger查看结果