Android實現MediaPlayer與Http Proxy結合使用示例（二）

        第一篇實現一個簡單的代理服務器與Android的MediaPlayer結合(僅支持Http Get)，可以通過代理服務器來轉發MediaPlayer的Request以及傳輸服務器的Response，但是還不能支持Seek，這次提高篇支持了Seek。代理服務器可以增強MediaPlayer對復雜的Http情況的適應，可以播放帶防盜鏈的媒體文件，邊播邊存，還可以對大體積的媒體文件（如視頻）進行多線程預加載，達到快速播放的效果。

       本文代碼運行在模擬器上，使用Microsoft Network Monitor 3.4來抓包，通過抓包可以發現seek的操作會重新連接服務器，並在Http Get請求中加入Range 字段，所以代理服務器每次監聽到MediaPlayer的request都需要新建socket與遠程服務器連接。

本文的代碼可以到http://download.csdn.net/detail/hellogv/4332362下載，本文程序運行效果如圖：

接下來貼出核心代碼HttpGetProxy.java：

public class HttpGetProxy { 
    final static private String TAG = "HttpGetProxy"; 
    final static private String LOCAL_IP_ADDRESS = "127.0.0.1"; 
    final static private int HTTP_PORT = 80; 
     
    private int local_ip_port; 
    private ServerSocket localServer = null; 
    private Socket localSocket = null; 
    private Socket remoteSocket = null; 
    private String remoteHost; 
 
    private InputStream in_remoteSocket; 
    private OutputStream out_remoteSocket; 
    private InputStream in_localSocket; 
    private OutputStream out_localSocket; 
 
    private SocketAddress address; 
    private interface OnFinishListener { 
        void onFinishListener(); 
    } 
 
    /** 
     * 初始化代理服務器 
     * @param localport 代理服務器監聽的端口 
     */ 
    public HttpGetProxy(int localport) { 
        local_ip_port=localport; 
        try { 
            localServer = new ServerSocket(localport, 1, 
                    InetAddress.getByName(LOCAL_IP_ADDRESS)); 
        } catch (UnknownHostException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } catch (IOException e) { 
            // TODO Auto-generated catch block 
            e.printStackTrace(); 
        } 
    } 
 
    /** 
     * 結束時，清除所有資源 
     */ 
    private OnFinishListener finishListener = new OnFinishListener() { 
 
        @Override 
        public void onFinishListener() { 
            System.out.println("..........release all.........."); 
            Log.e(TAG, "..........release all.........."); 
            try { 
                in_localSocket.close(); 
                out_remoteSocket.close(); 
 
                in_remoteSocket.close(); 
                out_localSocket.close(); 
 
                localSocket.close(); 
                remoteSocket.close(); 
            } catch (IOException e) { 
                // TODO Auto-generated catch block 
                e.printStackTrace(); 
            } 
        } 
    }; 
 
 
    /** 
     * 把網絡URL轉為本地URL，127.0.0.1替換網絡域名 
     * @param url 網絡URL 
     * @return 本地URL 
     */ 
    public String getLocalURL(String url){ 
        String result = null; 
        URI originalURI=URI.create(url); 
        remoteHost=originalURI.getHost(); 
        if(originalURI.getPort()!=-1){//URL帶Port 
            address = new InetSocketAddress(remoteHost, 
                    originalURI.getPort());//使用默認端口 
            result=url.replace(remoteHost+":"+originalURI.getPort(), 
                    LOCAL_IP_ADDRESS+":"+local_ip_port); 
        } 
        else{//URL不帶Port 
            address = new InetSocketAddress(remoteHost, 
                    HTTP_PORT);//使用80端口 
            result=url.replace(remoteHost,LOCAL_IP_ADDRESS+":"+local_ip_port); 
        } 
        return result; 
         
    } 
     
    /** 
     * 啟動代理服務器 
     * @throws IOException 
     */ 
    public void startProxy() throws IOException { 
         
        new Thread() { 
            public void run() { 
                int bytes_read; 
                byte[] local_request = new byte[1024]; 
                byte[] remote_reply = new byte[1024]; 
                while (true) { 
                    try { 
                        //-------------------------------------- 
                        //監聽MediaPlayer的請求，MediaPlayer->代理服務器 
                        //-------------------------------------- 
                        localSocket = localServer.accept(); 
 
                        Log.e(TAG, "..........localSocket connected.........."); 
                        in_localSocket = localSocket.getInputStream(); 
                        out_localSocket = localSocket.getOutputStream(); 
                        Log.e(TAG, "..........init local Socket I/O.........."); 
 
                        String buffer = "";//保存MediaPlayer的HTTP請求 
                        while ((bytes_read = in_localSocket.read(local_request)) != -1) { 
                            String str = new String(local_request); 
                            Log.e("localSocket---->", str); 
                            buffer = buffer + str; 
                            if (buffer.contains("GET") 
                                    && buffer.contains("\r\n\r\n")) { 
                                // ---把request中的本地ip改為遠程ip---// 
                                buffer = buffer.replace(LOCAL_IP_ADDRESS,remoteHost); 
                                break; 
                            } 
                        } 
                        Log.e(TAG, "..........local finish receive.........."); 
 
                        //-------------------------------------- 
                        //把MediaPlayer的請求發到網絡服務器，代理服務器->網絡服務器 
                        //-------------------------------------- 
                        remoteSocket = new Socket(); 
                        remoteSocket.connect(address); 
                        Log.e(TAG,"..........remote Server connected.........."); 
                        in_remoteSocket = remoteSocket.getInputStream(); 
                        out_remoteSocket = remoteSocket.getOutputStream(); 
                        out_remoteSocket.write(buffer.getBytes());//發送MediaPlayer的請求 
                        out_remoteSocket.flush(); 
 
                        //------------------------------------------------------ 
                        //把網絡服務器的反饋發到MediaPlayer，網絡服務器->代理服務器->MediaPlayer 
                        //------------------------------------------------------ 
                        Log.e(TAG,"..........remote start to receive.........."); 
                        while ((bytes_read = in_remoteSocket.read(remote_reply)) != -1) { 
                            out_localSocket.write(remote_reply, 0, bytes_read); 
                            out_localSocket.flush(); 
                        } 
                        Log.e(TAG, "..........over.........."); 
                        finishListener.onFinishListener();//釋放資源 
                    } catch (IOException e) { 
                        // TODO Auto-generated catch block 
                        e.printStackTrace(); 
                    } 
                } 
            } 
        }.start(); 
    } 
}