websocket传传图片

参考[url]http://www.adobe.com/devnet/archive/html5/articles/real-time-data-exchange-in-html5-with-websockets.html
[/url]
server端还是用tomcat7的方式
客户端

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">    
<html>    
<head>    
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">    
<title>Insert title here</title>    
</head>    

<body onload="startServer()">  
<canvas id="myCanvas" width="400px" height="500px">myCanvas</canvas>  
<canvas id="yourCanvas" width="400px" height="500px">yourCanvas</canvas>  
<div id="chatdiv" width="400px" height="500px">chatdiv</div> 

<input type="text" id="textMessage" size="20" />    
<input type="button" onclick="sendMessage()" value="Send">   
<input type="button" onclick="sendphoto()" value="sendphoto">    
</body> 
<script type="text/javascript">
	var myCanvas=document.getElementById("myCanvas");  
	var context=myCanvas.getContext('2d');  
	var imagewidth=myCanvas.width;
    var imageheight=myCanvas.height;
	var yourCanvas=document.getElementById("yourCanvas");  
	var context2=yourCanvas.getContext('2d'); 
	var image = new Image();  
	image.src = "haoba.jpg";  
	image.onload = function(){  
	    context.drawImage(image,0,0);  
	    var imgData=context.getImageData(50,50,200,200);  
	    context2.putImageData(imgData,10,260);  
	    //ctx.putImageData(imgData,200,260,50,50,100,100);  
	};  

    var ws = null;    
    function startServer() {    
        var url = "ws://192.168.137.27:8081/hao/msg";    
        if ('WebSocket' in window) {    
            ws = new WebSocket(url);    
        } else if ('MozWebSocket' in window) {    
            ws = new MozWebSocket(url);    
        } else {    
            alert('浏览器不支持');    
            return;  
        }    
        ws.binaryType = "arraybuffer";
        ws.onopen = function() {    
            alert('Opened!');    
        };    
        // 收到服务器发送的文本消息, event.data表示文本内容    
        ws.onmessage = function(event) { 
        	if(event.data instanceof ArrayBuffer){
		        var bytearray = new Uint8Array(event.data);
		        var tempcanvas = yourCanvas;
	            tempcanvas.height = imageheight;
	            tempcanvas.width = imagewidth;
		        var tempcontext = tempcanvas.getContext('2d');
		        var imgdata = tempcontext.getImageData(0,0,imagewidth,imageheight);
		        var imgdatalen = imgdata.data.length;
		        for(var i=8;i<imgdatalen;i++){
		            imgdata.data[i] = bytearray[i];
		        }
		        tempcontext.putImageData(imgdata,0,0);
		        var img = document.createElement('img');
		            img.height = imageheight;
		            img.width = imagewidth;
		            img.src = tempcanvas.toDataURL();
		        var chatdiv=document.getElementById("chatdiv");
		        chatdiv.appendChild(img);
		        chatdiv.innerHTML = chatdiv.innerHTML + "<br />";
		    }else{
		    	alert('Receive message: ' + event.data);    
		    }

        };    
        ws.onclose = function() {    
          alert('Closed!');    
        }   
        ws.onerror = function(err){
        	alert(err);
        }; 
	}    
    //发送信息    
    function sendMessage(){    
        var textMessage=document.getElementById("textMessage").value;    

        if(ws!=null&&textMessage!=""){    
            ws.send(textMessage);    
        }    
    }    

    function sendphoto(){
	    imagedata = context.getImageData(0, 0, imagewidth,imageheight);
	    var canvaspixelarray = imagedata.data;
	    var canvaspixellen = canvaspixelarray.length;
	    var bytearray = new Uint8Array(canvaspixellen);
	    for (var i=0;i<canvaspixellen;++i) {
	        bytearray[i] = canvaspixelarray[i];
	    }
	    ws.send(bytearray.buffer);
	    context.fillStyle = '#000000';
	    context.fillRect(0, 0, imagewidth,imageheight);    
	}
</script>  
</html>    

tomcat7下的服务端
HelloWorldWebSocketServlet.java

package com.hao;


import java.io.DataInputStream;
import java.io.IOException;
import java.io.PrintWriter;
import java.net.Socket;
import java.net.UnknownHostException;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Map;
import java.util.Random;

import javax.servlet.http.HttpServletRequest;

import org.apache.catalina.websocket.MessageInbound;
import org.apache.catalina.websocket.StreamInbound;
import org.apache.catalina.websocket.WebSocketServlet;
import org.apache.catalina.websocket.WsOutbound;

public class HelloWorldWebSocketServlet extends WebSocketServlet {
	public static Map<String,MyMessageInbound> mmiList  = new HashMap<String,MyMessageInbound>();

	protected StreamInbound createWebSocketInbound(String subProtocol,
			HttpServletRequest arg1) {
		return new MyMessageInbound();
	}
	public int getUserCount(){
		return mmiList.size();
	}
	private class MyMessageInbound extends MessageInbound {
		WsOutbound myoutbound;
		String mykey;
		@Override
		public void onOpen(WsOutbound outbound) {
			try {
				System.out.println("Open Client.");
				this.myoutbound = outbound;
				mykey =""+System.currentTimeMillis();;
				mmiList.put(mykey, this);
				System.out.println("mmiList size:"+mmiList.size());
				outbound.writeTextMessage(CharBuffer.wrap("open "+mykey));
			} catch (IOException e) {
				e.printStackTrace();
			}
		}

		@Override
		public void onClose(int status) {
			System.out.println("Close Client.");
			//mmiList.remove(this);
			mmiList.remove(mykey);
		}

		@Override
		protected void onBinaryMessage(ByteBuffer arg0) throws IOException {
			System.out.println("websocket-----onBinaryMessage:"+arg0.toString());
			for (Map.Entry<String, MyMessageInbound> entry : mmiList.entrySet()) {
					System.out.println(entry.getKey()+"--bin---");
					MyMessageInbound mmib = (MyMessageInbound) entry.getValue(); 
					mmib.myoutbound.writeBinaryMessage(arg0);
					mmib.myoutbound.flush();
			}
		}

		@Override
		protected void onTextMessage(CharBuffer message) throws IOException {
			System.out.println("onText--->" + message.toString());
			String[] msgarray= message.toString().split(",");
			for (Map.Entry<String, MyMessageInbound> entry : mmiList.entrySet()) {
				System.out.println(entry.getKey()+"-----");
				  MyMessageInbound mmib = (MyMessageInbound) entry.getValue(); 
				  CharBuffer buffer = CharBuffer.wrap(message);
				  System.out.println(buffer);
	              mmib.myoutbound.writeTextMessage(buffer);
	              mmib.myoutbound.flush();
			}
		}
	}


}

tomcat的配置文件：

<?xml version="1.0" encoding="ISO-8859-1"?>
<web-app 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"
  version="3.0"
  metadata-complete="true">
<servlet>
      <servlet-name>haomsg</servlet-name>
      <servlet-class>com.hao.HelloWorldWebSocketServlet</servlet-class>
    </servlet>
    <servlet-mapping>
      <servlet-name>haomsg</servlet-name>
      <url-pattern>/hao/msg</url-pattern>
    </servlet-mapping>
</web-app>