Implementation of web chat room

Hello everyone , I meet you again , I'm your friend, Quan Jun .

Back end ：

package com.jsx.chat;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.HashMap;
import java.util.Map;
import java.util.concurrent.CopyOnWriteArraySet;

import javax.websocket.OnClose;
import javax.websocket.OnError;
import javax.websocket.OnMessage;
import javax.websocket.OnOpen;
import javax.websocket.Session;
import javax.websocket.server.PathParam;
import javax.websocket.server.ServerEndpoint;

import net.sf.json.JSONObject;
@ServerEndpoint("/websocket/{userId}")
public class ChatServer {
	private static final SimpleDateFormat DATE_FORMAT = new SimpleDateFormat("yyyy-MM-dd HH:mm");	//  Date formatting 
	// Static variables , To record the current number of online connections . It should be designed to be thread safe .
	private static int onlineCount = 0;
	//concurrent Thread safety of package Set, Used to store the corresponding MyWebSocket object . If you want to realize the communication between the server and the single client , have access to Map To hold the , among Key It can identify the user 
	private static CopyOnWriteArraySet<ChatServer> webSocketSet = new CopyOnWriteArraySet<ChatServer>();
	// A connection session with a client , It is needed to send data to the client 
	private Session session;
	private String userId;
	/**
	*  Connection establishment method called successfully 
	* @param session   Optional parameters .session For a connection session with a client , It is needed to send data to the client 
	*/
	@OnOpen
	public void open(@PathParam("userId")String userIds,Session session) {
		//  Add initialization operation 
		System.out.println("--- initialization ----userId:"+userIds);
		this.session = session;
		// Get the id
		this.userId = userIds;
		
		webSocketSet.add(this);     // Join in set in 
		addOnlineCount();           // The online number 1
		System.out.println(" New connections are added ！ The current online population is " + getOnlineCount());
	}
	
	/**
	 *  Accept client messages , And send the message to all connected sessions 
	 * @param message  Messages from clients 
	 * @param session  Client's session 
	 */
	@OnMessage
	public void getMessage(String message, Session session1) {
		//  Parse the client message into JSON object 
		JSONObject jsonObject = JSONObject.fromObject(message);
		//  Add the sending date to the message 
		jsonObject.put("date", DATE_FORMAT.format(new Date()));
		// ----------------------- Send messages to all connected sessions --------------------------------
		System.out.println(" Message from the client "+this.userId+":" + message);
        for(ChatServer item: webSocketSet){
             try {
            	 // The right side of the current user displays , The left side of non users displays 
            	 if(this.userId.equals(item.userId)){jsonObject.put("isSelf", true);}
            	 else{jsonObject.put("isSelf", false);}
     			 //  send out JSON Formatted message 
            	 item.sendMessage(jsonObject.toString());
             } catch (IOException e) {
                 e.printStackTrace();
                 continue;
             }
         }
        
	}
	

	@OnClose
	public void close() {
		//  Add actions when closing a session 
		webSocketSet.remove(this);  // from set Delete in 
		subOnlineCount();           // The online number minus 1
		System.out.println(" There is a connection closed ！ The current online population is " + getOnlineCount());
	}

	
	@OnError
	public void error(Throwable t) {
		//  Add actions to handle errors 
		System.out.println(" An error occurred ");
		t.printStackTrace();
	}
	
	
	/**
      *  This method is different from the above methods . There is no comment , It is a method added according to your own needs .
      * @param message json news 
      * @throws IOException
      */
     public synchronized  void  sendMessage(String message) throws IOException{
         this.session.getAsyncRemote().sendText(message);
     }
 
     public static synchronized int getOnlineCount() {
         return onlineCount;
     }
 
     public static synchronized void addOnlineCount() {
    	 ChatServer.onlineCount++;
     }
 
     public static synchronized void subOnlineCount() {
    	 ChatServer.onlineCount--;
     }
	
}

Copy

front end :

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<!DOCTYPE html>
<html lang="zh">
<head>
<meta charset="utf-8">
<meta http-equiv="X-UA-Compatible" content="IE=edge">
<meta name="viewport" content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no">
<title> Instant group chat </title>
<meta name="renderer" content="webkit">
<meta http-equiv="Cache-Control" content="no-siteapp" />
<link rel="stylesheet" href="css/chat.css">
<link rel="alternate icon" href="assets/i/favicon.ico">
<link rel="stylesheet" href="assets/css/amazeui.min.css">
<link rel="stylesheet" href="assets/css/app.css">
<link href="umeditor/themes/default/css/umeditor.css" rel="stylesheet">
<style>
* {
	margin: 0;
	padding: 0;
}
 .chat-content-container {
	height: 29rem;
	overflow-y: auto;
	border: 1px solid silver;
	border-bottom: 0px;
} 
.container{
	border: 1px solid #cdcaca;
	padding:0px 0px;
}
.am-u-sm-6{
	left:0px;
}
.am-u-sm-push-6{
	width:100%;
}
</style>
</head>
<body>
	<input id="username" type="hidden" value="${user.username}"><br>
	<input id="name" type="hidden" value="${user.name}"><br>
	<!--  Chat content box starts  -->
	<div class="am-container container" >
		<div class="am-u-sm-12" style="background:#dcad50;">
			<!-- <div class="am-u-sm-3 am-u-sm-push-6"> -->
				<h3 style="text-align:center;margin-top:auto;margin-bottom:auto;padding:3px 0px;font-size:20px"> The chat room </h3>
			<!-- </div> -->
		</div>
		<div class="chat-content-container">
			<div class="am-u-sm-6 am-u-sm-push-6">
				<ul id="message-list" class="am-comments-list am-comments-list-flip"></ul>
			</div>
		</div>
<!-- 	</div> -->
	<!--  The chat content box ends  -->
	<div class="message-input am-margin-top">
		<!--  Enter the content box to start  -->
		<div class="am-g am-g-fixed" style="padding:10px 0px;border-top:1px solid #b5a4a4">
			<div class="am-u-sm-12">
				<form class="am-form">
					<div class="am-form-group">
						<script type="text/plain" id="myEditor" style="width: 100%;height: 20rem;"></script>
					</div>
				</form>
			</div>
		</div>
		<!--  Enter the nickname box to start  -->
		<!-- <div class="am-g am-g-fixed am-margin-top"> -->
			<div class="am-u-sm-6" style="display: none;">
				<div id="message-input-nickname" class="am-input-group am-input-group-primary">
					<span class="am-input-group-label"><i class="am-icon-user"></i></span>
					<input id="nickname" type="text" class="am-form-field" value="${user.name}"/>
				</div>
			</div>
			<div class="am-u-sm-12">
				<p style="text-align:right;margin:0px">
					<button onclick="f()" class="am-btn am-btn-warning">
						 close 
					</button>
					<button id="send" type="button" class="send am-btn am-btn-primary">
						<i class="am-icon-send"></i> send out 
					</button>
				</p>
			</div>
	<!-- 	</div> -->
<!-- 	</div> -->
	</div>
	</div>
	<script src="assets/js/jquery.min.js"></script>
	<script charset="utf-8" src="umeditor/umeditor.config.js"></script>
	<script charset="utf-8" src="umeditor/umeditor.min.js"></script>
	<script src="umeditor/lang/zh-cn/zh-cn.js"></script>
	
	<script>
	function f(){
		window.location.href="friend.jsp";
	}
	$(function() {
			var id = $('#username').val();
			var name = $('#name').val();
		    // Random method     Generate id Simulated users 
		    function rand(num){
		    	return parseInt(id);
		    }
			//  Initialize the message input box 
			var um = UM.getEditor('myEditor');
			//  Get the nickname box into focus 
			$('#nickname')[0].focus();
			//  newly build WebSocket object , final /WebSocket With the server side @ServerEndpoint("/websocket") Corresponding 
			//var socket = new WebSocket('ws://${pageContext.request.getServerName()}:${pageContext.request.getServerPort()}${pageContext.request.contextPath}/websocket');
			//var socket = new WebSocket("ws://localhost:8080/Chat/websocket");
			var target = "ws://"+window.location.host+"/Chat/websocket"+"/"+rand();
			//alert(target);
			var socket = new WebSocket(target);
			//  Process the data sent by the server 
			socket.onmessage = function(event) {
				addMessage(event.data);
			};
			
			
			//  Click on Send Button 
			$('#send').on('click', function() {
				var nickname = $('#nickname').val();
				//alert(um.getContent()); // Content 
				//alert(nickname);	// nickname 
				if (!um.hasContents()) {	//  Judge whether the message input box is empty 
					//  The message input box gets the focus 
					um.focus();
					//  Add dithering effect 
					$('.edui-container').addClass('am-animation-shake');
					setTimeout("$('.edui-container').removeClass('am-animation-shake')", 1000);
				} else if (nickname == '') {	//  Determine whether the nickname box is empty 
					// The nickname box gets the focus 
					$('#nickname')[0].focus();
					//  Add dithering effect 
					$('#message-input-nickname').addClass('am-animation-shake');
					setTimeout("$('#message-input-nickname').removeClass('am-animation-shake')", 1000);
				} else {
					//  Send a message 
					socket.send(JSON.stringify({
						content : um.getContent(),
						nickname : name
					}));
					//  Clear the message input box 
					um.setContent('');
					//  The message input box gets the focus 
					um.focus();
				}
			});

			//  Add a message to the chat 
			function addMessage(message) {
				message = JSON.parse(message);
				var messageItem = '<li class="am-comment '
						+ (message.isSelf ? 'am-comment-flip' : 'am-comment')
						+ '">'
						+ '<a href="javascript:void(0)" ><img src="assets/images/'
						+ (message.isSelf ? 'self.jpg' : 'others.jpg')
						+ '" alt="" class="am-comment-avatar" width="48" height="48"/></a>'
						+ '<div class="am-comment-main"><header class="am-comment-hd"><div class="am-comment-meta">'
						+ '<a href="javascript:void(0)" class="am-comment-author">'
						+ message.nickname + '</a> <time>' + message.date
						+ '</time></div></header>'
						+ '<div class="am-comment-bd">' + message.content
						+ '</div></div></li>';
				$(messageItem).appendTo('#message-list');
				//  Scroll the scroll bar to the bottom 
				$(".chat-content-container").scrollTop($(".chat-content-container")[0].scrollHeight);
			}
		});
	</script>
	
</body>
</html>

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Because my account design, database and other operations , Therefore, if you want to test directly, you can modify the above nickname The value in is randomly generated ！

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