背景介绍
近一个月完成了公司的一个项目,负责即时聊天部分
寻找了一下,决定使用websocket,要问原因的话,因为tomcat 自带相关消息收发的API,用起来方便
闲话少叙,进入实现步骤
使用工具 java 1.6 tomcat 7.0.27以上版本(以下版本不支持websocket),本人使用的是 7.0.42版本
先概括说一下:(看着迷糊没关系,下面有提供完整源码,可以下载后运行 ,结合效果自行分析)
先写一个,消息处理类,继承 tomcat的catalina.jar的MessageInbound类,并创建一个构造方法获取登录名
继承onPen,onClose等方法对用户上线下线进行监听,重写onTextMessage(CharBuffer msg)方法,
实现消息的处理,接收和发送
再写一个网页应用必须的servlet类接收界面请求,继承WebSocketServlet类,实现登陆监控
既然是即时聊天,则需要知道在线用户有哪些,则需要一个在线用户容器类
另外,消息send(),参数只有一个,所以里面会包含消息发送者和消息接收者,需要解析,所以写了一个解析类
那么开始详细代码解释
package socket; import java.io.IOException; import java.nio.ByteBuffer; import java.nio.CharBuffer; import java.util.HashMap; import org.apache.catalina.websocket.MessageInbound; import org.apache.catalina.websocket.WsOutbound; import util.MessageUtil; public class MyMessageInbound extends MessageInbound { // 用户姓名 private String name; public MyMessageInbound() { super(); } public MyMessageInbound(String name) { super(); this.name = name; } @Override protected void onBinaryMessage(ByteBuffer arg0) throws IOException { } @Override protected void onTextMessage(CharBuffer msg) throws IOException { // 用户所发消息处理后的map HashMap<String,String> messageMap = MessageUtil.getMessage(msg); //处理消息类 // 在线用户集合类map HashMap<String, MessageInbound> userMsgMap = InitServlet.getSocketMap(); String fromName = messageMap.get("fromName"); // 消息来源 String toName = messageMap.get("toName"); // 消息接收人 //获取该用户 MessageInbound messageInbound = userMsgMap.get(toName); //在容器中获得接收人的MessageInbound MessageInbound messageFromInbound = userMsgMap.get(fromName); //在容器中获得发送人的MessageInbound if(messageInbound!=null && messageFromInbound!=null){ // 如果发往人 存在进行操作 WsOutbound outbound = messageInbound.getWsOutbound(); WsOutbound outFromBound = messageFromInbound.getWsOutbound(); String content = messageMap.get("content"); // 消息内容 String msgContentString = fromName + "说: " + content; // 构造消息体 //发出去内容 CharBuffer toMsg = CharBuffer.wrap(msgContentString.toCharArray()); CharBuffer fromMsg = CharBuffer.wrap(msgContentString.toCharArray()); // 消息发送到前端 outFromBound.writeTextMessage(fromMsg); outbound.writeTextMessage(toMsg); // outFromBound.flush(); outbound.flush(); } } @Override protected void onClose(int status) { // 用户离线后 在线用户容器 去除该用户 InitServlet.getSocketMap().remove(this); super.onClose(status); } @Override protected void onOpen(WsOutbound outbound) { super.onOpen(outbound); // if(name!=null){ // 用户登录后,存入在线用户容器 InitServlet.getSocketMap().put(name, this); } } @Override public int getReadTimeout() { return 0; } }
然后是 请求接收类
package socket; import javax.servlet.http.HttpServletRequest; import org.apache.catalina.websocket.StreamInbound; import org.apache.catalina.websocket.WebSocketServlet; public class MyWebSocketServlet extends WebSocketServlet { /** * */ private static final long serialVersionUID = -6488889268352650321L; public String getUser(HttpServletRequest request){ String userName = (String) request.getSession().getAttribute("user"); if(userName==null){ return null; } return userName; } @Override protected StreamInbound createWebSocketInbound(String arg0, HttpServletRequest request) { System.out.println("用户" + request.getSession().getAttribute("user") + "登录"); return new MyMessageInbound(this.getUser(request)); } }
在线用户容器初始化类
package socket; import java.util.HashMap; import javax.servlet.ServletConfig; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import org.apache.catalina.websocket.MessageInbound; /** * 应用启动时加载此类 * 初始化servlet * 在应用启动后 在线用户的容器就准备好了! * @author masan * */ public class InitServlet extends HttpServlet { private static final long serialVersionUID = 5772968684237694231L; // 在线用户容器 (存储在线用户 键值对 name:MessageInbound) private static HashMap<String,MessageInbound> socketMap; public void init(ServletConfig config) throws ServletException { InitServlet.socketMap = new HashMap<String,MessageInbound>(); super.init(config); System.out.println("Server Started!"); } /** * 获取在线用户容器的方法 * @return */ public static HashMap<String,MessageInbound> getSocketMap() { return InitServlet.socketMap; } }
然后是 消息体的解析类,我是按照逗号分隔的 前两处分别为发送者和接收者姓名,后一处为消息内容
package util; import java.nio.CharBuffer; import java.util.HashMap; public class MessageUtil { public static HashMap<String,String> getMessage(CharBuffer msg) { HashMap<String,String> map = new HashMap<String,String>(); String msgString = msg.toString(); String m[] = msgString.split(","); map.put("fromName", m[0]); map.put("toName", m[1]); map.put("content", m[2]); return map; } }
那么附上工程目录结构:
附上三个JSP的内容
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Index</title> <script type="text/javascript" src="js/jquery-1.7.2.min.js"></script> <%session.setAttribute("user", "小化");%> <script type="text/javascript"> var ws = null; function startWebSocket() { if (‘WebSocket‘ in window) ws = new WebSocket("ws://localhost:8080/WebSocketUser/websocket.do"); else if (‘MozWebSocket‘ in window) ws = new MozWebSocket("ws://localhost:8080/WebSocketUser/websocket.do"); else alert("not support"); ws.onmessage = function(evt) { // alert(evt.data); console.log(evt); // $("#xiaoxi").val(evt.data); setMessageInnerHTML(evt.data); }; function setMessageInnerHTML(innerHTML){ document.getElementById(‘message‘).innerHTML += innerHTML + ‘<br/>‘; } ws.onclose = function(evt) { //alert("close"); document.getElementById(‘denglu‘).innerHTML="离线"; }; ws.onopen = function(evt) { //alert("open"); document.getElementById(‘denglu‘).innerHTML="在线"; document.getElementById(‘userName‘).innerHTML=‘小化‘; }; } function sendMsg() { var fromName = "小化"; var toName = document.getElementById(‘name‘).value; //发给谁 var content = document.getElementById(‘writeMsg‘).value; //发送内容 ws.send(fromName+","+toName+","+content); } </script> </head> <body > <p>聊天功能实现</p> 登录状态: <span id="denglu" style="color:red;">正在登录</span> <br> 登录人: <span id="userName"></span> <br> <br> <br> 发送给谁:<input type="text" id="name" value="小明"></input> <br> 发送内容:<input type="text" id="writeMsg"></input> <br> 聊天框:<div id="message" style="height: 250px;width: 280px;border: 1px solid; overflow: auto;"></div> <br> <input type="button" value="send" onclick="sendMsg()"></input> </body> </html>
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <!DOCTYPE html> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>Index</title> <script type="text/javascript" src="js/jquery-1.7.2.min.js"></script> <%session.setAttribute("user", "小明");%> <script type="text/javascript"> var ws = null; function startWebSocket() { if (‘WebSocket‘ in window) ws = new WebSocket("ws://localhost:8080/WebSocketUser/websocket.do"); else if (‘MozWebSocket‘ in window) ws = new MozWebSocket("ws://localhost:8080/WebSocketUser/websocket.do"); else alert("not support"); ws.onmessage = function(evt) { console.log(evt); //alert(evt.data); //$("#xiaoxi").val(evt.data); setMessageInnerHTML(evt.data); }; function setMessageInnerHTML(innerHTML){ document.getElementById(‘message‘).innerHTML += innerHTML + ‘<br/>‘; } ws.onclose = function(evt) { //alert("close"); document.getElementById(‘denglu‘).innerHTML="离线"; }; ws.onopen = function(evt) { //alert("open"); document.getElementById(‘denglu‘).innerHTML="在线"; document.getElementById(‘userName‘).innerHTML="小明"; }; } function sendMsg() { var fromName = "小明"; var toName = document.getElementById(‘name‘).value; //发给谁 var content = document.getElementById(‘writeMsg‘).value; //发送内容 ws.send(fromName+","+toName+","+content); } </script> </head> <body > <p>聊天功能实现</p> 登录状态: <span id="denglu" style="color:red;">正在登录</span> <br> 登录人: <span id="userName"></span> <br> <br> <br> 发送给谁:<input type="text" id="name" value="小化"></input> <br> 发送内容:<input type="text" id="writeMsg"></input> <br> 聊天框:<div id="message" style="height: 250px;width: 280px;border: 1px solid; overflow: auto;"></div> <br> <input type="button" value="send" onclick="sendMsg()"></input> </body> </html>
附上两个JSP,可自行增加,
另:附上web.xml ,相当重要,里面进行了servlet配置,并且设置了要求
initServlet在应用启动时就要执行
<?xml version="1.0" encoding="UTF-8"?> <web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd"> <servlet> <servlet-name>websocket</servlet-name> <servlet-class>socket.MyWebSocketServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>websocket</servlet-name> <url-pattern>*.do</url-pattern> </servlet-mapping> <servlet> <servlet-name>initServlet</servlet-name> <servlet-class>socket.InitServlet</servlet-class> <load-on-startup>1</load-on-startup> </servlet> <welcome-file-list> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
注意事项:1.js代码内的websocket 构造参数里的IP 要和最终浏览器访问地址一致 要么都是localhost要么都是IP 否则跨域
2.这个demo内是根据用户名识别用户的,明显不能做到唯一,所以只能是个demo,要用到项目里,请考虑下然后稍作修改即可
(我生产项目里用的mysql数据库,最后使用的用户ID来做区别)
3.消息发送参数只有一个,那么发送者和接收者的信息一并发送,后台有个解析类,如果需要传递其他参数,可自行修改解析类的解析方案
完整代码下载地址
http://download.csdn.net/download/u012580998/9941412