# 利刃出鞘_Tomcat 核心原理解析（十一）-- Tomcat 附加功能 WebSocket -- 2

利刃出鞘_Tomcat 核心原理解析（十一）-- Tomcat 附加功能 WebSocket – 2

一、Tomcat专题 - WebSocket - 案例 - 登录功能

1、在项目 dzs168_chat_room 中，导入 tomcat 项目依赖（ dzs168_chat_room/web/lib/ ）


idea ---> File
---> Project Structure 
---> Modules 选择我们的项目 dzs168_chat_room---> Dependencies:  点击 + 添加---> Library...---> Application Server Libraries---> Tcomcat ---> Add Selected---> Apply 
---> OK。

2、项目 dzs168_chat_room 中，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，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 -->

4、在项目 dzs168_chat_room 中，创建用户登录的 servlet 类 LoginServlet.java

/***  project_tomcat\dzs168_chat_room\src\djh\it\servlet\LoginServlet.java**  2024-9-1 创建 用户登录的 servlet 类 LoginServlet.java*/package djh.it.servlet;import com.alibaba.fastjson.JSON;import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.HashMap;
import java.util.Map;@WebServlet(name = "loginServlet",urlPatterns = "/login")
public class LoginServlet extends HttpServlet {private static final String PASSWORD = "dzs168";@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//处理中文乱码问题resp.setCharacterEncoding("UTF-8");//1. 接收页面传递的参数 , 用户名/密码String username = req.getParameter("username");String password = req.getParameter("password");Map resultMap = new HashMap();//2. 判定用户名密码是否正确//3. 如果正确, 响应登录成功的信息if(PASSWORD.equals(password)){resultMap.put("success",true);resultMap.put("message","登录成功");req.getSession().setAttribute("username",username);}else{//4. 如果不正确, 响应登录失败的信息resultMap.put("success",false);resultMap.put("message","用户名或密码错误");}//5. 响应数据resp.getWriter().write(JSON.toJSONString(resultMap));}@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {doPost(req,resp);}
}

5、运行 tomcat 服务，进行测试。浏览器地址栏输入：localhost:8080/ 输入错误密码和正确密码，分别进行测试。

二、Tomcat专题 - WebSocket - 案例 - OnOpen

1、在项目 dzs168_chat_room 中，工具类 MessageUtil.java

/***  project_tomcat.dzs168_chat_room.src.djh.it.utils.MessageUtil.java**  2024-9-2 工具类 MessageUtil.java*/
package djh.it.utils;import com.alibaba.fastjson.JSON;import java.util.HashMap;
import java.util.Map;public class MessageUtil {public final static String TYPE = "type";public final static String DATA = "data";public final static String FROM_NAME = "fromName";public final static String TO_NAME = "toName";public final static String TYPE_MESSAGE = "message";public final static String TYPE_USER = "user";//组装消息, 然后返回一个json格式的消息数据public static String getContent(String type, String fromName, String toName, String content) {Map<String, Object> userMap = new HashMap<String, Object>();userMap.put(MessageUtil.TYPE, type);userMap.put(MessageUtil.DATA, content);userMap.put(MessageUtil.FROM_NAME, fromName);userMap.put(MessageUtil.TO_NAME, toName);String jsonMsg = JSON.toJSONString(userMap);return jsonMsg;}
}

2、在项目 dzs168_chat_room 中，创建获取 HttpSession 的 GetHttpSessionConfigurator.java 类，

/***  project_tomcat\dzs168_chat_room\src\djh\it\websocket\GetHttpSessionConfigurator.java**  2024-9-2 创建 获取 HttpSession 的 GetHttpSessionConfigurator.java 类，*/package djh.it.websocket;import javax.servlet.http.HttpSession;
import javax.websocket.HandshakeResponse;
import javax.websocket.server.HandshakeRequest;
import javax.websocket.server.ServerEndpointConfig;public class GetHttpSessionConfigurator extends ServerEndpointConfig.Configurator {@Override  //重写方法public void modifyHandshake(ServerEndpointConfig config, HandshakeRequest request, HandshakeResponse response) {HttpSession httpSession = (HttpSession) request.getHttpSession();config.getUserProperties().put(HttpSession.class.getName(),httpSession);}
}

3、在项目 dzs168_chat_room 中，创建 websocket 类 ChatSocket.java

/***   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 javax.servlet.http.HttpSession;
import javax.websocket.*;
import javax.websocket.server.ServerEndpoint;
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();}// 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 --;}}