在线聊天室 --- WebSocket练手Demo

Posted 2021-05-21 满眼*星辰

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WebSocket练手Demo

WebSocket练手Demo

WebSocket练手Demo

服务器代码

package org.example.test;

import javax.websocket.*;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;

@ServerEndpoint(value="/test/{userId}")
public class TestWebSocket {
    private String userId = null;

    @OnOpen
    public void onOpen(@PathParam("userId") String userId, Session session) {
        this.userId = userId;
        System.out.println("打开连接: " + userId);
    }

    @OnClose
    public void onClose() {
        System.out.println("关闭连接: " + userId);
    }

    @OnMessage
    public void onMessage(String message, Session session) throws IOException {
        System.out.println("收到消息! " + userId + ": " + message);
        session.getBasicRemote().sendText(message);
    }

    @OnError
    public void onError(Session session, Throwable error) {
        System.out.println("连接出现错误! " + this.userId);
        error.printStackTrace();
    }
}

客户端代码

<!DOCTYPE html>
<html>
<head>
    <meta charset="UTF-8">
    <title></title>
</head>
<body>
userId: 1 <br />
<input id="text" type="text" />
<button onclick="send()"> Send </button>
<button onclick="closeWebSocket()"> Close </button>
<div id="message">   </div>

<script type="text/javascript">
      //判断当前浏览器是否支持WebSocket
      if('WebSocket' in window){
          websocket = new WebSocket("ws://localhost:8080/java_chatroom/test/1");
          console.log("link success")
      }else{
          alert('Not support websocket')
      }

      //连接发生错误的回调方法
      websocket.onerror = function(){
          setMessageInnerHTML("error");
      };

      //连接成功建立的回调方法
      websocket.onopen = function(event){
          setMessageInnerHTML("open");
      }

      //接收到消息的回调方法
      websocket.onmessage = function(event){
          setMessageInnerHTML(event.data);
      }

      //连接关闭的回调方法
      websocket.onclose = function(){
          setMessageInnerHTML("close");
      }

      //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
      window.onbeforeunload = function(){
          websocket.close();
      }

      //将消息显示在网页上
      function setMessageInnerHTML(innerHTML){
          document.getElementById('message').innerHTML += innerHTML + '<br/>';
      }

      //关闭连接
      function closeWebSocket(){
          websocket.close();
      }

      //发送消息
      function send(){
          var message = document.getElementById('text').value;
          websocket.send(message);
      }
    </script>

</body>
</html>