基于Tomcat的WebSocket
- - ITeye博客之前大概的看过WebSocket,当时Tomcat还不支持WebSocket,所以当时写了一篇基于Jetty的WebSocket实现,地址如下:. 现在Tomcat7.0.27发布了,从这个版本开始Tomcat就支持WebSocket了. Tomcat的WebSocket和Jetty的大致上差不多,大同小异,这里就简单的贴两个类吧:. 
之前大概的看过WebSocket,当时Tomcat还不支持WebSocket,所以当时写了一篇基于Jetty的WebSocket实现,地址如下:
http://redstarofsleep.iteye.com/blog/1307608
现在Tomcat7.0.27发布了,从这个版本开始Tomcat就支持WebSocket了。
Tomcat的WebSocket和Jetty的大致上差不多,大同小异,这里就简单的贴两个类吧:
第一个类,这个和Jetty一样,需要一个Servlet来处理WebSocket请求:
package lhc.websocket;
import org.apache.catalina.websocket.StreamInbound;
import org.apache.catalina.websocket.WebSocketServlet;
public class MyWebSocketServlet extends WebSocketServlet {
	private static final long serialVersionUID = -7178893327801338294L;
	@Override
	protected StreamInbound createWebSocketInbound(String arg0) {
System.out.println("##########");
		return new MyMessageInbound();
	}
}
 这个Servlet继承自WebSocketServlet,实现createWebSocketInbound方法。该方法返回第二个类的实例。
第二个类,处理每一次具体的WebSocket任务:
package lhc.websocket;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import org.apache.catalina.websocket.MessageInbound;
public class MyMessageInbound extends MessageInbound {
	@Override
	protected void onBinaryMessage(ByteBuffer arg0) throws IOException {
		// TODO Auto-generated method stub
		
	}
	@Override
	protected void onTextMessage(CharBuffer msg) throws IOException {
System.out.println("~~~~~~~:" + msg);
		
	}
}
 这个类继承自MessageInbound类,必须实现onBinaryMessage和onTextMessage方法。Jetty中只有一个onMessage方法,而Tomcat细化成了2个方法。
最后,web.xml中进行一下Servlet的配置。
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xmlns:web="http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
  <display-name>wsoc</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  
  <servlet>
  	<servlet-name>mywebsocket</servlet-name>
  	<servlet-class>lhc.websocket.MyWebSocketServlet</servlet-class>
  </servlet>
  <servlet-mapping>
  	<servlet-name>mywebsocket</servlet-name>
  	<url-pattern>*.do</url-pattern>
  </servlet-mapping>
</web-app>
 
页面的话,就是标准的HTML5的websocket,这个和服务器是否是Tomcat或者Jetty是无关的:
<%@ 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">
var ws = null;
function startWebSocket() {
	if ('WebSocket' in window)
		ws = new WebSocket("ws://localhost:8080/wsoc/mywebsocket.do");
	else if ('MozWebSocket' in window)
		ws = new MozWebSocket("ws://localhost:8080/wsoc/mywebsocket.do");
	else
		alert("not support");
	
	
	ws.onmessage = function(evt) {
		alert(evt.data);
	};
	
	ws.onclose = function(evt) {
		alert("close");
	};
	
	ws.onopen = function(evt) {
		alert("open");
	};
}
function sendMsg() {
	ws.send(document.getElementById('writeMsg').value);
}
</script>
</head>
<body onload="startWebSocket();">
<input type="text" id="writeMsg"></input>
<input type="button" value="send" onclick="sendMsg()"></input>
</body>
</html>