java WebSocket實現簡單的聊天室（包括群發和點對點聊天）

2019-11-06 06:02:44

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來源：轉載

供稿：網友

今天突然看到了WebSocket然后就網上找了一個例子，然后修改了下，實現了簡單的聊天室，包括群聊和點對點聊天。

使用的代碼如下

jsp代碼：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%><%String path = request.getContextPath();String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";%><!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"><html>  <head>    <base href="<%=basePath%>">        <title>My JSP 'socket.jsp' starting page</title>    	<meta http-equiv="PRagma" content="no-cache">	<meta http-equiv="cache-control" content="no-cache">	<meta http-equiv="expires" content="0">    	<meta http-equiv="keyWords" content="keyword1,keyword2,keyword3">	<meta http-equiv="description" content="This is my page">	<!--	<link rel="stylesheet" type="text/CSS" href="styles.css">	-->  <style type="text/css">          input#chat {              width: 410px          }            #console-container {              width: 400px;          }            #console {              border: 1px solid #CCCCCC;              border-right-color: #999999;              border-bottom-color: #999999;              height: 170px;              overflow-y: scroll;              padding: 5px;              width: 100%;          }            #console p {              padding: 0;              margin: 0;          }      </style>      <script type="application/Javascript">         "use strict";            var Chat = {};            Chat.socket = null;            Chat.connect = (function(host) {              if ('WebSocket' in window) {                  Chat.socket = new WebSocket(host);              } else if ('MozWebSocket' in window) {                  Chat.socket = new MozWebSocket(host);              } else {                  Console.log('Error: 瀏覽器不支持WebSocket');                  return;              }                Chat.socket.onopen = function () {                  Console.log('Info: WebSocket鏈接已打開');                  document.getElementById('chat').onkeydown = function(event) {                      if (event.keyCode == 13) {                          Chat.sendMessage();                      }                  };              };                Chat.socket.onclose = function () {                  document.getElementById('chat').onkeydown = null;                  Console.log('Info: webcocket關閉.');              };                Chat.socket.onmessage = function (message) {                  Console.log(message.data);              };          });            Chat.initialize = function() {              if (window.location.protocol == 'http:') {                  Chat.connect('ws://' + window.location.host + '/gtweb/chat');              } else {                  Chat.connect('wss://' + window.location.host + '/gtweb/chat');              }          };            Chat.sendMessage = (function() {              var message = document.getElementById('chat').value;              if (message != '') {                  Chat.socket.send(message);                  document.getElementById('chat').value = '';              }          });            var Console = {};            Console.log = (function(message) {              var console = document.getElementById('console');              var p = document.createElement('p');              p.style.wordWrap = 'break-word';              p.innerHTML = message;              console.appendChild(p);              while (console.childNodes.length > 25) {                  console.removeChild(console.firstChild);              }              console.scrollTop = console.scrollHeight;          });            Chat.initialize();            document.addEventListener("DOMContentLoaded", function() {              // Remove elements with "noscript" class - <noscript> is not allowed in XHTML              var noscripts = document.getElementsByClassName("noscript");              for (var i = 0; i < noscripts.length; i++) {                  noscripts[i].parentNode.removeChild(noscripts[i]);              }          }, false);        </script>  </head>  <body>  <div class="noscript"><h2 style="color: #ff0000">Seems your browser doesn't support Javascript! Websockets rely on Javascript being enabled. Please enable      Javascript and reload this page!</h2></div>  <div>      <p>          <input type="text" placeholder="輸入文字，回車發送" id="chat" /><br>        注意：輸入  消息to用戶名   發送給指定用戶   比如：  你好to用戶1<br>                       輸入   消息     直接發送給全體用戶        </p>      <div id="console-container">          <div id="console"/>      </div>  </div>  </body></html>后臺代碼：
/** *  ━━━━━━神獸出沒━━━━━━  *　　　┏┓　　　┏┓  *　　┏┛┻━━━┛┻┓  *　    ┃　　　　　　　┃ *　	  ┃　　　━　　　┃  *　    ┃　┳┛　┗┳    ┃  *　　┃　　　　　　　┃  *　　┃　　　┻　　　┃  *　　┃　　　　　　　┃  *　　┗━┓　　　┏━┛Code is far away from bug with the animal protecting  *　　　　┃　　　┃    神獸保佑,代碼無bug  *　　　　┃　　　┃  *　　　　┃　　　┗━━━┓  *　　　　┃　　　　　　　┣┓  *　　　　┃　　　　　　　┏┛  *　　　　┗┓┓┏━┳┓┏┛  *　　　　　┃┫┫　┃┫┫  *　　　　　┗┻┛　┗┻┛  *  * ━━━━━━感覺萌萌噠━━━━━━  */package gt.controller.admin;import java.io.IOException;import java.util.Set;import java.util.concurrent.CopyOnWriteArraySet;import java.util.concurrent.atomic.AtomicInteger;import javax.websocket.OnClose;import javax.websocket.OnError;import javax.websocket.OnMessage;import javax.websocket.OnOpen;import javax.websocket.session;import javax.websocket.server.ServerEndpoint;import org.springframework.web.bind.annotation.RequestMapping;/** * 類名稱:ChatAnnotation.java 類描述:簡單的聊天室 作 者:why 時 間:2017年3月7日 */@ServerEndpoint(value = "/chat")public class ChatAnnotation {	private static final String GUEST_PREFIX = "用戶";	/**	 * 一個提供原子操作的Integer的類。在Java語言中，++i和i++操作并不是線程安全的，	 * 在使用的時候，不可避免的會用到synchronized關鍵字。 而AtomicInteger則通過一種線程安全的加減操作接口。	 */	private static final AtomicInteger connectionIds = new AtomicInteger(0);	private static final Set<ChatAnnotation> connections = new CopyOnWriteArraySet<>();	private final String nickname;	private Session session;	public ChatAnnotation() {		nickname = GUEST_PREFIX + connectionIds.getAndIncrement();	}	/**	 * 創建連接時間調用的方法	 * 	 * @param session	 */	@OnOpen	public void start(Session session) {		this.session = session;		connections.add(this);		String message = String.format("* %s %s", nickname, "加入聊天室");		//上線通知		broadcast(message);		try {			//系統問候語			SendHello(this.nickname);			//返回在線用戶			onlineList();		} catch (IOException e) {			e.printStackTrace();		}			}	/**	 * 鏈接關閉時調用方法	 */	@OnClose	public void end() {		connections.remove(this);		String message = String.format("* %s %s", nickname, "退出聊天室");		broadcast(message);	}	/**	 * 傳輸信息過程中調用方法	 * @param message	 */	@OnMessage	public void incoming(String message) {		// Never trust the client		// TODO: 過濾輸入的內容		String m = String.format("* %s %s", nickname, message);		if(m.contains("to")){			//點對點發送			broadcastOneToOne(m,nickname);		}else{			//群發			broadcast(m);		}	}	/**	 * 發生錯誤是調用方法	 * @param t	 * @throws Throwable	 */	@OnError	public void onError(Throwable t) throws Throwable {		System.out.println("錯誤: " + t.toString());	}	/**	 * 消息廣播	 * 通過connections，對所有其他用戶推送信息的方法	 * @param msg	 */	private static void broadcast(String msg) {		for (ChatAnnotation client : connections) {			try {				synchronized (client) {					client.session.getBasicRemote().sendText(msg);				}			} catch (IOException e) {				System.out.println("錯誤:向客戶端發送消息失敗");				connections.remove(client);				try {					client.session.close();				} catch (IOException e1) {					e1.printStackTrace();				}				String message = String.format("* %s %s", client.nickname,"退出聊天室");				broadcast(message);			}		}	}	/**	 * 點對點發送消息	 * 通過connections，對所有其他用戶推送信息的方法	 * @param msg	 */	private static void broadcastOneToOne(String msg, String nickName) {		String[] arr = msg.split("to");		for (ChatAnnotation client : connections) {			try {				if(arr[1].equals(client.nickname) || nickName.equals(client.nickname)){					synchronized (client) {						client.session.getBasicRemote().sendText(arr[0]);					}				}			} catch (IOException e) {				System.out.println("錯誤:向客戶端發送消息失敗");				connections.remove(client);				try {					client.session.close();				} catch (IOException e1) {					e1.printStackTrace();				}				String message = String.format("* %s %s", client.nickname,"退出聊天室");				broadcast(message);			}		}	}	//系統問候語	private static void SendHello(String nickName) throws IOException{		String m = String.format("* %s %s", nickName, "你好");		for (ChatAnnotation client : connections) {			if(client.nickname.equals(nickName)){				client.session.getBasicRemote().sendText(m);			}		}	}	//在線用戶	private static void onlineList() throws IOException{		String online = "";		for (ChatAnnotation client : connections) {			if(online.equals("")){				online = client.nickname;			}else{				online += ","+client.nickname;			}		}		String m = String.format("* %s %s", "當前在線用戶", online);		for (ChatAnnotation client : connections) {			client.session.getBasicRemote().sendText(m);		}	}}注釋都加在代碼中了，到此簡單的聊天室就可以使用了。
如圖所示。