# 利刃出鞘_Tomcat 核心原理解析（十一）-- Tomcat 附加功能 WebSocket -- 3

利刃出鞘_Tomcat 核心原理解析（十一）-- Tomcat 附加功能 WebSocket – 3

一、Tomcat专题 - WebSocket - 案例 - OnMessage分析

1、WebSocket DEMO 案例实现流程分析：OnMessage 分析

2、在项目 dzs168_chat_room 中，在 websocket 类 ChatSocket.java 中，

创建 public void onMessage(String message, Session session) {…} 方法。分析流程。

//{"fromName":"Deng","toName":"HEIMA","content":"约会呀"}@OnMessagepublic  void onMessage(String message, Session session) {//1. 获取客户端的信息内容, 并解析//2. 判定是否有接收人//3. 如果接收人是否是广播(all), 如果是, 则说明发送广播消息//4. 不是all , 则给指定的用户推送消息}

二、Tomcat专题 - WebSocket - 案例 - OnMessage功能实现

1、在项目 dzs168_chat_room 中，在 websocket 类 ChatSocket.java 中，

完成 onMessage(String message, Session session) {…} 方法代码编写。

//{"fromName":"Deng","toName":"HEIMA","content":"约会呀"}@OnMessagepublic  void onMessage(String message, Session session) throws IOException {System.out.println("onMessage : name = " + httpSession.getAttribute("username")+ ", message=" + message );//1. 获取客户端的信息内容, 并解析Map<String,String> messageMap = JSON.parseObject(message, Map.class);String fromName = messageMap.get("fromName");String toName = messageMap.get("toName");String content = messageMap.get("content");//2. 判定是否有接收人if(toName == null || toName.isEmpty()){return;}//3. 如果接收人是否是广播(all), 如果是, 则说明发送广播消息String messageContent = MessageUtil.getContent(MessageUtil.TYPE_MESSAGE, fromName, toName, content);System.out.println("服务端给客户端发送消息, 消息内容: " + messageContent);if("all".equals(toName)){//3.1 组装消息内容broadcastAllUsers(messageContent);}else{//4. 不是all , 则给指定的用户推送消息singlePushMessage(messageContent, fromName,toName);}}

2、在项目 dzs168_chat_room 中，在 websocket 类 ChatSocket.java 中，

创建 //给指定用户推送消息 private void singlePushMessage(String content, String fromName, String toName) throws IOException {…} 方法，并完成代码编写。

//给指定用户推送消息private void singlePushMessage(String content, String fromName, String toName) throws IOException {boolean isOnline = false;//1. 判定当然接收人是否在线for (HttpSession hsession : onlineUsers.keySet()) {if(toName.equals(hsession.getAttribute("username"))){isOnline = true;}}//2. 如果存在, 发送消息if(isOnline){for (HttpSession hsession : onlineUsers.keySet()) {if (hsession.getAttribute("username").equals(fromName) || hsession.getAttribute("username").equals(toName)){onlineUsers.get(hsession).session.getBasicRemote().sendText(content);}}}}

3、项目 dzs168_chat_room 中，websocket 类 ChatSocket.java 代码。


/***   project_tomcat\dzs168_chat_room\src\djh\it\websocket\ChatSocket.java**   2024-9-2 创建 websocket 类 ChatSocket.java*/package djh.it.websocket;import djh.it.utils.MessageUtil;
import com.alibaba.fastjson.JSON;import javax.servlet.http.HttpSession;
import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;@ServerEndpoint(value = "/websocket",configurator = GetHttpSessionConfigurator.class )
public class ChatSocket {private  Session session;private  HttpSession httpSession;//保存当前系统中登录的用户的HttpSession信息, 及对应的Endpoint实例信息private static Map<HttpSession , ChatSocket> onlineUsers = new HashMap<HttpSession, ChatSocket>();private static int onlineCount = 0;@OnOpenpublic void onOpen(Session session, EndpointConfig config){//1. 记录webSocket的会话信息对象Sessionthis.session = session;//2. 获取当前登录用户HttpSession信息.HttpSession httpSession = (HttpSession) config.getUserProperties().get(HttpSession.class.getName());this.httpSession = httpSession;System.out.println("当前登录用户 : " + httpSession.getAttribute("username") +", Endpoint : " +hashCode());//3. 记录当前登录用户信息, 及对应的Endpoint实例if (httpSession.getAttribute("username") != null){onlineUsers.put(httpSession,this);}//4. 获取当前所有登录用户 --------> DZS168,dzs,TOM...String names = getNames();//5. 组装消息 ---> {"data":"dzs168,Deng,study","toName":"","fromName":"","type":"user"}String message = MessageUtil.getContent(MessageUtil.TYPE_USER, "", "", names);//6. 通过广播的形式发送消息//session.getBasicRemote().sendText("");broadcastAllUsers(message);//7. 记录当前用户登录数 .incrCount();}//{"fromName":"Deng","toName":"HEIMA","content":"约会呀"}@OnMessagepublic  void onMessage(String message, Session session) throws IOException {System.out.println("onMessage : name = " + httpSession.getAttribute("username")+ ", message=" + message );//1. 获取客户端的信息内容, 并解析Map<String,String> messageMap = JSON.parseObject(message, Map.class);String fromName = messageMap.get("fromName");String toName = messageMap.get("toName");String content = messageMap.get("content");//2. 判定是否有接收人if(toName == null || toName.isEmpty()){return;}//3. 如果接收人是否是广播(all), 如果是, 则说明发送广播消息String messageContent = MessageUtil.getContent(MessageUtil.TYPE_MESSAGE, fromName, toName, content);System.out.println("服务端给客户端发送消息, 消息内容: " + messageContent);if("all".equals(toName)){//3.1 组装消息内容broadcastAllUsers(messageContent);}else{//4. 不是all , 则给指定的用户推送消息singlePushMessage(messageContent, fromName,toName);}}//给指定用户推送消息private void singlePushMessage(String content, String fromName, String toName) throws IOException {boolean isOnline = false;//1. 判定当然接收人是否在线for (HttpSession hsession : onlineUsers.keySet()) {if(toName.equals(hsession.getAttribute("username"))){isOnline = true;}}//2. 如果存在, 发送消息if(isOnline){for (HttpSession hsession : onlineUsers.keySet()) {if (hsession.getAttribute("username").equals(fromName) || hsession.getAttribute("username").equals(toName)){onlineUsers.get(hsession).session.getBasicRemote().sendText(content);}}}}// 发送广播消息private void broadcastAllUsers(String message) {for (HttpSession hsession : onlineUsers.keySet()) {try {onlineUsers.get(hsession).session.getBasicRemote().sendText(message);} catch (Exception e) {e.printStackTrace();}}}//获取所有的在线用户private String getNames() {String names = "";if(onlineUsers.size()>0){for (HttpSession hsession : onlineUsers.keySet()) {String username = (String) hsession.getAttribute("username");names += username+",";}}return names.substring(0,names.length()-1);}public int getOnlineCount(){return onlineCount;}public synchronized void incrCount(){onlineCount ++;}public synchronized void decrCount(){onlineCount --;}}

三、Tomcat专题 - WebSocket - 案例 - OnMessage功能测试

1、项目 dzs168_chat_room 中，前端源码 chat.jsp 页面。


<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html lang="en">
<head><meta charset="utf-8"><meta http-equiv="X-UA-Compatible" content="IE=edge"><meta name="format-detection" content="telephone=no"><meta http-equiv="X-UA-Compatible" content="IE=edge,chrome=1"><meta name="viewport" content="width=device-width, initial-scale=1.0, user-scalable=0, minimum-scale=1.0, maximum-scale=1.0"><meta name="mobile-web-app-capable" content="yes"><meta name="apple-mobile-web-app-capable" content="yes"><meta content="yes" name="apple-mobile-web-app-capable"><meta content="yes" name="apple-touch-fullscreen"><meta name="full-screen" content="yes"><meta content="default" name="apple-mobile-web-app-status-bar-style"><meta name="screen-orientation" content="portrait"><meta name="browsermode" content="application"><meta name="msapplication-tap-highlight" content="no"><meta name="x5-orientation" content="portrait"><meta name="x5-fullscreen" content="true"><meta name="x5-page-mode" content="app"><base target="_blank"><title>段子手168-聊天室</title><link href="css/bootstrap.min.css" rel="stylesheet" type="text/css"/><link rel="stylesheet" href="css/chat.css"><script src="js/jquery-1.9.1.min.js"></script><script type="text/javascript"><%String name = session.getAttribute("username")+"";%>var self = "<%= name %>";</script><script type="text/javascript" src="js/ws.js"></script>
</head><body  onload="startWebSocket(self);"><img style="width:100%;height:100%" src="img/chat_bg.jpg"><div class="abs cover contaniner"><div class="abs cover pnl"><div class="top pnl-head" style="padding: 20px ; color: white;" id="userName"></div><div class="abs cover pnl-body" id="pnlBody"><div class="abs cover pnl-left"><div class="abs cover pnl-msgs scroll" id="show"><div class="pnl-list" id="hists"><!-- 历史消息 --></div><div class="pnl-list" id="msgs"><!-- 消息这展示区域 --></div></div><div class="abs bottom pnl-text"><div class="abs cover pnl-input"><textarea class="scroll" id="context_text" onkeydown="sendMessage(self)" wrap="hard" placeholder="在此输入文字信息..."></textarea><div class="abs atcom-pnl scroll hide" id="atcomPnl"><ul class="atcom" id="atcom"></ul></div></div><div class="abs br pnl-btn" id="submit" style="background-color: rgb(32, 196, 202); color: rgb(255, 255, 255);" onclick="sendMsg(self)">发送</div><div class="pnl-support" id="copyright"><a href="http://www.itcast.cn">段子手168,版本所有</a></div></div></div><div class="abs right pnl-right"><div class="slider-container hide"></div><div class="pnl-right-content"><div class="pnl-tabs"><div class="tab-btn active" id="hot-tab">好友列表</div></div><div class="pnl-hot"><ul class="rel-list unselect" id="userlist"></ul></div></div><div class="pnl-right-content"><div class="pnl-tabs"><div class="tab-btn active">系统广播</div></div><div class="pnl-hot"><ul class="rel-list unselect" id="broadcastList"></ul></div></div></div></div></div>
</div>
</body>
</html>
<!-- project_tomcat\dzs168_chat_room\web\chat.jsp -->

2、项目 dzs168_chat_room 中，前端源码 login.jsp 页面。


<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<html lang="en">
<head><title>段子手聊天室——登录</title><meta name="viewport" content="width=device-width, initial-scale=1"/><meta http-equiv="Content-Type" content="text/html; charset=utf-8"/><meta name="keywords"content="Transparent Sign In Form Responsive Widget,Login form widgets, Sign up Web forms , Login signup Responsive web form,Flat Pricing table,Flat Drop downs,Registration Forms,News letter Forms,Elements"/><script type="application/x-javascript">addEventListener("load", function () {setTimeout(hideURLbar, 0);}, false);function hideURLbar() {window.scrollTo(0, 1);}</script><script src="js/jquery-1.9.1.min.js"></script><link rel="icon" href="img/chat.ico" type="image/x-icon"/><link rel="stylesheet" href="css/font-awesome.css"/> <!-- Font-Awesome-Icons-CSS --><link rel="stylesheet" href="css/login.css" type="text/css" media="all"/> <!-- Style-CSS -->
</head><body class="background">
<div class="header-w3l"><h1>段子手168聊天室</h1>
</div>
<div class="main-content-agile"><div class="sub-main-w3"><h2>登录</h2><form><div class="icon1"><input placeholder="用户名" id="username" type="text"/></div><div class="icon2"><input placeholder="密码" id="password" type="password"/></div><div class="clear"></div><input type="button" value="登录" onclick="login()"/></form></div>
</div>
<div class="footer"><p>段子手168 版权所有Copyright 2024-9-1  All Rights Reserved </p>
</div>
</body>
<script type="text/javascript">function login() {$.ajax({type: 'POST',url: '/login',dataType: 'json',data: {username: $("#username").val(),password: $("#password").val()},success: function (data) {if (data.success) {window.location.href = "chat.jsp";} else {alert(data.message);}}});}</script>
</html>
<!-- project_tomcat\dzs168_chat_room\web\login.jsp -->

3、项目 dzs168_chat_room 中，//定义全局的webSocket对象 ws.js 源码。

…\project_tomcat\dzs168_chat_room\web\js\ws.js

//定义全局的webSocket对象
var ws = null;function startWebSocket(self) {//构建WebSocket对象if ('WebSocket' in window) {ws = new WebSocket("ws://localhost:8080/websocket");} else if ('MozWebSocket' in window) {ws = new MozWebSocket("ws://localhost:8080/websocket");} else {alert("not support");}//监听消息， 有消息传递， 会触发此方法ws.onmessage = function (evt) {var _data = evt.data;console.log(">> : " + _data);var o = JSON.parse(_data);if (o.type == 'message') { //如果后端, 响应的是消息, 在页面展示setMessageInnerHTML(o, self);} else if (o.type == 'user') { // 如果服务端响应的是用户列表, 在界面展示用户列表var userArry = o.data.split(',');$("#userlist").empty();$("#userlist").append('<li class="rel-item"><input type="radio" name="toUser" value="all">广播</input></li>');$.each(userArry, function (n, value) {if (value != self && value != 'admin') {$("#userlist").append('<li class="rel-item"><input type="radio"  name="toUser" value="'+value+'">'+value+'</input></li>');$("#broadcastList").append('<li class="rel-item">您的好友 '+value+' 已上线</li>');}});}};//关闭链接时触发ws.onclose = function (evt) {$('#userName').html("用户： "+ self +"<span style='float: right;color: red'>离线</span>");};//打开时触发ws.onopen = function (evt) {$('#userName').html("用户： "+ self +"<span style='float: right;color: green'>在线</span>");};
}function setMessageInnerHTML(msg, self) {//根据后台响应的数据, 判定是展示在左侧还是右侧.var str = "";if(msg.toName == 'all'){$("#broadcastList").append('<li class="rel-item"> 系统广播消息： '+msg.data+' </li>');}else if (msg.fromName == self) {str = "<div class=\"msg guest\"><div class=\"msg-right\"><div class=\"msg-host headDefault\"></div><div class=\"msg-ball\" title=\"今天 17:52:06\">" + msg.data + "</div></div></div>"} else if(msg.toName == self){str = "<div class=\"msg robot\"><div class=\"msg-left\" worker=\"" + msg.fromName + "\"><div class=\"msg-host photo\" style=\"background-image: url(../img/avatar/Member002.jpg)\"></div><div class=\"msg-ball\" title=\"今天 17:52:06\">" + msg.data + "</div></div></div>";}//获取到现有的内容, 追加新的消息内容var msgs = document.getElementById("msgs");msgs.innerHTML = msgs.innerHTML + str;//判定消息来源的用户 , 勾选对应的好友信息var a = $('input[name="toUser"]');for(var i=0 ; i < a.length ; i++){if(a[i].value == msg.fromName){console.log(a[i]);a[i].checked='checked';}}
}// 组装消息, 发送消息
function sendMsg(self) {var content = $("#context_text").val();if(!content){alert('请输入消息内容');return ;}var message = {};message.fromName = self;message.toName = $('input:radio:checked').val();  //根据界面勾选的用户, 来决定消息发送给谁message.content = content; //获取输入文本框中输入的内容var msg = JSON.stringify(message);console.log(" msg: "+msg);ws.send(msg);//发送消息$("#context_text").val(''); //将输入框内容置为空
}function sendMessage(self){if(event.keyCode == 13){sendMsg(self);}
}

4、运行 tomcat 服务，进行测试。

5、多个浏览器地址栏输入：localhost:8080/ 登录几个不同用户，进行测试。

四、Tomcat专题 - WebSocket - 案例 - OnClose及OnError介绍

1、在项目 dzs168_chat_room 中，在 websocket 类 ChatSocket.java 中，

创建 public void onClose(Session session, CloseReason closeReason){…} 方法。

@OnClosepublic void onClose(Session session, CloseReason closeReason){decrCount();System.out.println("客户端关闭了一个连接 , 当前在线人数 : " + getOnlineCount());}

2、在项目 dzs168_chat_room 中，在 websocket 类 ChatSocket.java 中，

创建 public void onError(Session session, Throwable throwable){…} 方法。

@OnErrorpublic void onError(Session session, Throwable throwable){throwable.printStackTrace();System.out.println("服务异常");}

3、项目 dzs168_chat_room 中，websocket 类 ChatSocket.java 代码。


/***   project_tomcat\dzs168_chat_room\src\djh\it\websocket\ChatSocket.java**   2024-9-2 创建 websocket 类 ChatSocket.java*/package djh.it.websocket;import djh.it.utils.MessageUtil;
import com.alibaba.fastjson.JSON;import javax.servlet.http.HttpSession;
import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;@ServerEndpoint(value = "/websocket",configurator = GetHttpSessionConfigurator.class )
public class ChatSocket {private  Session session;private  HttpSession httpSession;//保存当前系统中登录的用户的HttpSession信息, 及对应的Endpoint实例信息private static Map<HttpSession , ChatSocket> onlineUsers = new HashMap<HttpSession, ChatSocket>();private static int onlineCount = 0;@OnOpenpublic void onOpen(Session session, EndpointConfig config){//1. 记录webSocket的会话信息对象Sessionthis.session = session;//2. 获取当前登录用户HttpSession信息.HttpSession httpSession = (HttpSession) config.getUserProperties().get(HttpSession.class.getName());this.httpSession = httpSession;System.out.println("当前登录用户 : " + httpSession.getAttribute("username") +", Endpoint : " +hashCode());//3. 记录当前登录用户信息, 及对应的Endpoint实例if (httpSession.getAttribute("username") != null){onlineUsers.put(httpSession,this);}//4. 获取当前所有登录用户 --------> DZS168,dzs,TOM...String names = getNames();//5. 组装消息 ---> {"data":"dzs168,Deng,study","toName":"","fromName":"","type":"user"}String message = MessageUtil.getContent(MessageUtil.TYPE_USER, "", "", names);//6. 通过广播的形式发送消息//session.getBasicRemote().sendText("");broadcastAllUsers(message);//7. 记录当前用户登录数 .incrCount();}//{"fromName":"Deng","toName":"HEIMA","content":"约会呀"}@OnMessagepublic  void onMessage(String message, Session session) throws IOException {System.out.println("onMessage : name = " + httpSession.getAttribute("username")+ ", message=" + message );//1. 获取客户端的信息内容, 并解析Map<String,String> messageMap = JSON.parseObject(message, Map.class);String fromName = messageMap.get("fromName");String toName = messageMap.get("toName");String content = messageMap.get("content");//2. 判定是否有接收人if(toName == null || toName.isEmpty()){return;}//3. 如果接收人是否是广播(all), 如果是, 则说明发送广播消息String messageContent = MessageUtil.getContent(MessageUtil.TYPE_MESSAGE, fromName, toName, content);System.out.println("服务端给客户端发送消息, 消息内容: " + messageContent);if("all".equals(toName)){//3.1 组装消息内容broadcastAllUsers(messageContent);}else{//4. 不是all , 则给指定的用户推送消息singlePushMessage(messageContent, fromName,toName);}}//给指定用户推送消息private void singlePushMessage(String content, String fromName, String toName) throws IOException {boolean isOnline = false;//1. 判定当然接收人是否在线for (HttpSession hsession : onlineUsers.keySet()) {if(toName.equals(hsession.getAttribute("username"))){isOnline = true;}}//2. 如果存在, 发送消息if(isOnline){for (HttpSession hsession : onlineUsers.keySet()) {if (hsession.getAttribute("username").equals(fromName) || hsession.getAttribute("username").equals(toName)){onlineUsers.get(hsession).session.getBasicRemote().sendText(content);}}}}// 发送广播消息private void broadcastAllUsers(String message) {for (HttpSession hsession : onlineUsers.keySet()) {try {onlineUsers.get(hsession).session.getBasicRemote().sendText(message);} catch (Exception e) {e.printStackTrace();}}}//获取所有的在线用户private String getNames() {String names = "";if(onlineUsers.size()>0){for (HttpSession hsession : onlineUsers.keySet()) {String username = (String) hsession.getAttribute("username");names += username+",";}}return names.substring(0,names.length()-1);}@OnClosepublic void onClose(Session session, CloseReason closeReason){decrCount();System.out.println("客户端关闭了一个连接 , 当前在线人数 : " + getOnlineCount());}@OnErrorpublic void onError(Session session, Throwable throwable){throwable.printStackTrace();System.out.println("服务异常");}public int getOnlineCount(){return onlineCount;}public synchronized void incrCount(){onlineCount ++;}public synchronized void decrCount(){onlineCount --;}}