使用JavaWeb webSocket实现简易的点对点聊天功能实例代码

首先给大家声明一点：需要 jdk 7 ， tomcat需要支持websocket的版本 

1.InitServlet

   该类主要是用来初始化构造将来存储用户身份信息的map仓库，利用其初始化方法Init 初始化仓库， 利用其静态方法getSocketList 获得对应的用户身份信息。

   webSocket ，我认为MessageInbound 用来识别登录人的信息，用它来找到对应的人，推送消息。每次登录都会产生一个MessageInbound。

  这里的 HashMap<String,MessageInbound>    ：string 存储用户session的登录id,MessageInbound存储 推送需要的身份信息。以上属于个人口头话理解。

package socket;
import java.nio.CharBuffer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import javax.servlet.ServletConfig;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import org.apache.catalina.websocket.MessageInbound;
public class InitServlet extends HttpServlet {
  private static final long serialVersionUID = -L;
  //private static List<MessageInbound> socketList;  
  private static HashMap<String,MessageInbound> socketList;  
  public void init(ServletConfig config) throws ServletException {  
//    InitServlet.socketList = new ArrayList<MessageInbound>();  
    InitServlet.socketList = new HashMap<String,MessageInbound>();  
    super.init(config);  
    System.out.println("Server start============");  
  }  
  public static HashMap<String,MessageInbound> getSocketList() {  
    return InitServlet.socketList;  
  }  
/*  public static List<MessageInbound> getSocketList() {  
    return InitServlet.socketList;  
  }  
*/}

2.MyWebSocketServlet 

  websocket用来建立连接的servlet，建立连接时，首先在session获取该登录人的userId，在调用MyMessageInbound构造函数传入userId

package socket;
import java.io.IOException;
import java.io.PrintWriter;
import java.nio.CharBuffer;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.catalina.websocket.StreamInbound;
import org.apache.catalina.websocket.WebSocketServlet;
/**
*
* @ClassName: MyWebSocketServlet
* @Description: 建立连接时创立
* @author mangues
* @date --
*/
public class MyWebSocketServlet extends WebSocketServlet {
  public String getUser(HttpServletRequest request){
    String userName = (String) request.getSession().getAttribute("user");
    if(userName==null){
      return null;
    }
    return userName;
   // return (String) request.getAttribute("user");
  }
  @Override
  protected StreamInbound createWebSocketInbound(String arg,
      HttpServletRequest request) {
    System.out.println("##########");
    return new MyMessageInbound(this.getUser(request));
  }
}

3.onOpen方法调用InitServlet的map身份仓库，

放入用户userId 和 对应该登录用户的websocket身份信息MessageInbound （可以用userId来寻找到推送需要的 身份MessageInbound ）

 onTextMessage ：用来获取消息，并发送消息

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 {
  private String name;
  public MyMessageInbound() {
    super();
  }
  public MyMessageInbound(String name) {
    super();
    this.name = name;
  }
  @Override
  protected void onBinaryMessage(ByteBuffer arg) throws IOException {
    // TODO Auto-generated method stub
  }
  @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
    //上线用户集合类map
    HashMap<String, MessageInbound> userMsgMap = InitServlet.getSocketList();
    String fromName = messageMap.get("fromName");  //消息来自人 的userId
    String toName = messageMap.get("toName");     //消息发往人的 userId
    //获取该用户
    MessageInbound messageInbound = userMsgMap.get(toName);  //在仓库中取出发往人的MessageInbound
    if(messageInbound!=null){   //如果发往人 存在进行操作
      WsOutbound outbound = messageInbound.getWsOutbound();
      String content = messageMap.get("content"); //获取消息内容
      String msgContentString = fromName + "   " + content;  //构造发送的消息
      //发出去内容
      CharBuffer toMsg = CharBuffer.wrap(msgContentString.toCharArray());
      outbound.writeTextMessage(toMsg); //
      outbound.flush();
    }
   /* for (MessageInbound messageInbound : InitServlet.getSocketList()) {
      CharBuffer buffer = CharBuffer.wrap(msg);
      WsOutbound outbound = messageInbound.getWsOutbound();
      outbound.writeTextMessage(buffer);
      outbound.flush();
    } */
  }
  @Override
  protected void onClose(int status) {
    InitServlet.getSocketList().remove(this);
    super.onClose(status);
  }
  @Override
  protected void onOpen(WsOutbound outbound) {
    super.onOpen(outbound);
    //登录的用户注册进去
    if(name!=null){
      InitServlet.getSocketList().put(name, this);
    }
//    InitServlet.getSocketList().add(this);
  }
}

4.消息处理类，处理前端发来的消息

package util;
import java.nio.CharBuffer;
import java.util.HashMap;
/**
 *
 * @ClassName: MessageUtil
 * @Description: 消息处理类
 * @author mangues
* @date --
*/
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[]);
    map.put("toName", m[]);
    map.put("content", m[]);
    return map;
  }
}

5.web配置

<?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>mywebsocket</servlet-name>
 <servlet-class>socket.MyWebSocketServlet</servlet-class>
</servlet>
<servlet-mapping>
 <servlet-name>mywebsocket</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>

6,前端，为方便起见，我直接用了两个jsp，在其中用<％session.setAttribute("user","小明")％>；来表示登录。

      两个jsp没任何本质差别，只是用来表示两个不同的人登录，可以同两个浏览器打开不同的jsp，来聊天操作

   A.小化

<％@ page language="java" contentType="text/html; charset=UTF-"
  pageEncoding="UTF-"％>
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-">
<title>Index</title>
<script type="text/javascript" src="js/jquery ...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:/webSocket/mywebsocket.do");
  else if ('MozWebSocket' in window)
    ws = new MozWebSocket("ws://localhost:/webSocket/mywebsocket.do");
  else
    alert("not support");
  ws.onmessage = function(evt) {
    //alert(evt.data);
    console.log(evt);
    $("#xiaoxi").val(evt.data);
  };
  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 onload="startWebSocket();">
<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：<textarea rows="" cols="" readonly id="xiaoxi"></textarea>
<br>
<input type="button" value="send" onclick="sendMsg()"></input>
</body>
</html>

 B.小明

<％@ 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 2.1.1.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/webSocket/mywebsocket.do");
 else if ('MozWebSocket' in window)
   ws = new MozWebSocket("ws://localhost:8080/webSocket/mywebsocket.do");
 else
   alert("not support");
 ws.onmessage = function(evt) {
   console.log(evt);
   //alert(evt.data);
   $("#xiaoxi").val(evt.data);
 };
 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 onload="startWebSocket();">
<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：<textarea rows="13" cols="100" readonly id="xiaoxi"></textarea>
<br>
<input type="button" value="send" onclick="sendMsg()"></input>
</body>
</html>

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