我正在为 android 构建一个代理服务器，但我已经碰壁了。我迫切需要帮助。我对Android很陌生。所以，起初，我在 Java SE 中制作了代理服务器。代理服务器的工作方式如下：
它监听本地端口，
当客户端连接时，会创建一个新线程。每个线程也有一个名称。
HOST 是从请求中提取的。
客户端的请求然后被转发到远程地址（从主机获取）。
然后代理读取远程服务器的地址，直到找到-1。
然后将此响应转发给客户端。
代理服务器在笔记本电脑中运行。客户端是安卓手机的Youtube APP。手机已经root，我已经安装了ProxyDroid来告诉客户端代理服务器在哪里。使用了 ProxyDroid 的“全局代理”选项。
Java SE 中的代码：
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.InetAddress;
import java.net.NetworkInterface;
import java.net.ServerSocket;
import java.net.Socket;
import java.util.Enumeration;
class clientThread implements Runnable
{
Socket clientSocket = null;//each client socket.
Socket connectYoutubeServerSock = null;//This socket is used to write client's request to the
//YouTube Server.
int videoFlag = 0;//this flag determines whether the GET request is a video request or not.
final int BufferSize = 8019;
public String hostURL;
int youtubePort = 80;
//public DataOutputStream sendClientResponse = null;
public clientThread(Socket clientSocket)
{
this.clientSocket = clientSocket;
}
public void run()
{
System.out.println("Client connected: "+clientSocket.toString());
System.out.println("Current Thread Name: "+Thread.currentThread().getName());
try
{
byte youtubeAppReqArray[] = new byte[BufferSize];//this byte array will house youtube app's request!
InputStream youtubeAppReq = clientSocket.getInputStream();
// reading the request and put it into youtubeAppReqArray.
int bytesRead = youtubeAppReq.read(youtubeAppReqArray,0,BufferSize);
String youtubeAppReqString = new String(youtubeAppReqArray, 0, bytesRead);
System.out.println(youtubeAppReqString);
// extract the url of the GET request!
int gStart = youtubeAppReqString.indexOf("GET: ") + 4;
int gEnd = youtubeAppReqString.indexOf('\n', gStart);
String gURL = youtubeAppReqString.substring(gStart, gEnd - 9);
System.out.println("URL of GET: " + gURL);
//test if videoplayback is there or not?
if(gURL.indexOf("videoplayback") > -1 )
{
System.out.println("This is a video request!");
videoFlag = 1;
}
// extract the host to connect to
int hStart = youtubeAppReqString.indexOf("Host: ") + 6;
int hEnd = youtubeAppReqString.indexOf('\n', hStart);
String host = youtubeAppReqString.substring(hStart, hEnd - 1);
System.out.println("Connecting to host " + host);
//forward the youtube app request from proxy to the youtube server
Socket youtubeServerSocket = new Socket(host, 80);
OutputStream writeToYoutubeServerStream = youtubeServerSocket.getOutputStream();
System.out.println("Forwarding request to server");
writeToYoutubeServerStream.write(youtubeAppReqArray, 0, bytesRead);
writeToYoutubeServerStream.flush();
// forward the response from the server to the browser
byte youtubeServerResArray[] = new byte[BufferSize];//this byte array will house youtube server's response.
InputStream readFromYoutubeServerStream = youtubeServerSocket.getInputStream();
OutputStream writeToYoutubeAppStream = clientSocket.getOutputStream();
System.out.println("Forwarding request from server");
int remoteBytesRead;
do
{
remoteBytesRead = readFromYoutubeServerStream.read(youtubeServerResArray,0,BufferSize);
System.out.println("Receiving " + remoteBytesRead + " bytes");
if (remoteBytesRead > 0)
{
writeToYoutubeAppStream.write(youtubeServerResArray, 0, remoteBytesRead);
String rData = new String(youtubeServerResArray,0,remoteBytesRead);
System.out.println("Remote data: "+rData);
}
} while (remoteBytesRead > 0);
writeToYoutubeAppStream.flush();
youtubeServerSocket.close();
clientSocket.close();
System.out.println("End of communication");
}
catch(IOException ioe)
{
System.out.println("Error"+ioe.getMessage());
}
}
}
public class ChallengeProxy extends IOException
{
public static final int SERVERPORT = 4447;
public static int threadName = 0;
public static void main(String[] args)
{
ChallengeProxy proxyObj = new ChallengeProxy();
proxyObj.knowIP();//get the IP address of the local machine!
try
{
ServerSocket serverSocket = new ServerSocket(SERVERPORT);
System.out.println("Started on: "+SERVERPORT);
while(true)//Non stop listen for clients!
{
Socket clientSocket = serverSocket.accept();//blocks until client is connected!
System.out.println("Client connected: "+clientSocket.toString());
Thread t = new Thread(new clientThread(clientSocket), Integer.toString(threadName));
t.start();
threadName++;
}
}
catch (IOException ioe)
{
System.out.println("Could not listen on port: "+SERVERPORT);
System.out.println("Error"+ioe.getMessage());
}
catch(Exception e)
{
System.out.println("Error"+e.getMessage());
}
}
public void knowIP()
{
try
{
Enumeration e = NetworkInterface.getNetworkInterfaces();
while(e.hasMoreElements())
{
NetworkInterface ni = (NetworkInterface) e.nextElement();
System.out.println("Net interface: "+ni.getName());
Enumeration e2 = ni.getInetAddresses();
while (e2.hasMoreElements())
{
InetAddress ip = (InetAddress) e2.nextElement();
System.out.println("IP address: "+ ip.toString());
}
}
}
catch (Exception e)
{
e.printStackTrace();
}
}
}
这正是我想要的。现在，我稍微改造一下代码，让它在 Android 中运行。但是，下面的逻辑是相同的。同样，当新客户端连接时，也会创建一个新线程。Youtube APP 仍然是客户端。所以现在，YouTube APP 会请求驻留在同一台 Android 机器上的代理服务器。和以前一样，ProxyDroid 被配置为，YouTube APP 知道我的代理服务器在哪里运行。
Android的代码看起来像（这个代码在我得到第一个答案后进行了相应的修改并且它不完整，因为在完成之前代码已经开始显示严重错误！）：
public class ChallengeAndroidProxyActivity extends Activity
{
public static final int SERVERPORT = 4453;
public static int threadName = 0;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
(new Thread(new Runnable()
{
public void run()
{
startSocketServer();
}
}
)).start();
}
/*
* Here we will create an infinite loop that will listen
* for client connections.
*
* */
public void startSocketServer()
{
knowIP();// Now we find the IP address of the native machine.
String LOG_TAG = "SocketServerThread";
Log.i(LOG_TAG,"Inside the server thread! ");
try
{
ServerSocket serverSocket = new ServerSocket(SERVERPORT);
Log.i(LOG_TAG, "Started on : " + SERVERPORT);
threadName = 0;
while (true)// Non stop listen for clients!
{
Socket clientSocket = serverSocket.accept();
Log.d(LOG_TAG , "Client connected : " + clientSocket.toString());
Thread t = new Thread(new clientThread(clientSocket), Integer.toString(threadName));
t.start();
threadName++;
}
}
catch (IOException ioe)
{
Log.i(LOG_TAG, "Could not listen on port: " + SERVERPORT);
Log.i(LOG_TAG, "Error : " + ioe.getMessage());
}
catch (Exception e)
{
Log.i(LOG_TAG, "Error : " + e.getMessage());
}
}
class clientThread implements Runnable
{
String LOG_TAG = "clientSocketThread";
Socket clientSocket = null;//each client socket.
Socket connectYoutubeServerSock = null;//This socket is used to write client's request to the
//YouTube Server.
int videoFlag = 0;//this flag determines whether the GET request is a video request or not.
final int BufferSize = 8019;
public String hostURL;
int youtubePort = 80;
public clientThread(Socket clientSocket)
{
this.clientSocket = clientSocket;
}
public void run()
{
Log.i(LOG_TAG,"Client connected: "+clientSocket.toString());
Log.i(LOG_TAG,"Current Thread Name: "+Thread.currentThread().getName());
try
{//1
byte youtubeAppReqArray[] = new byte[BufferSize];//this byte array will house youtube app's request!
InputStream youtubeAppReq = clientSocket.getInputStream();
// reading the request and put it into youtubeAppReqArray.
int bytesRead = youtubeAppReq.read(youtubeAppReqArray,0,BufferSize);
String youtubeAppReqString = new String(youtubeAppReqArray, 0, bytesRead);
Log.i("Youtube App Request: ",youtubeAppReqString);
// extract the host to connect to
int hStart = youtubeAppReqString.indexOf("Host: ") + 6;
int hEnd = youtubeAppReqString.indexOf('\n', hStart);
String host = youtubeAppReqString.substring(hStart, hEnd - 1);
Log.i("Connecting to host ",host);
InetAddress addr = InetAddress.getByName(host);
int port = 80;
SocketAddress sockaddr = new InetSocketAddress(addr, port);
Socket youtubeServerSocket = new Socket();
youtubeServerSocket.connect(sockaddr);
OutputStream writeToYoutubeServerStream = youtubeServerSocket.getOutputStream();
//writeToYoutubeServerStream.write(youtubeAppReqArray, 0, bytesRead);
}//1
catch(IOException ioe)
{//1
Log.i("Error",ioe.getMessage());
}//1
}
}
/************************************************************************************/
public void knowIP()
{
This function just gets the IP of the native machine.
}
}
代码已根据第一个答案建议的更改进行了修改。当代码行
//writeToYoutubeServerStream.write(youtubeAppReqArray, 0, bytesRead);
被注释掉（通过这一行，我的代理将客户端的请求写入远程服务器），我从客户端获得的请求如下所示：
07-19 22:30:16.309: I/ApplicationPackageManager(2843): cscCountry is not German : NEE
07-19 22:30:16.399: I/Net interface:(2843): wlan0
07-19 22:30:16.429: I/IP address:(2843): /192.168.1.129
07-19 22:30:16.429: I/Net interface:(2843): lo
07-19 22:30:16.439: I/IP address:(2843): /127.0.0.1
07-19 22:30:16.439: I/SocketServerThread(2843): Inside the server thread!
07-19 22:30:16.439: I/SocketServerThread(2843): Started on : 4453
07-19 22:30:20.929: D/SocketServerThread(2843): Client connected : Socket[addr=/192.168.1.129,port=44276,localport=4453]
07-19 22:30:20.959: I/clientSocketThread(2843): Client connected: Socket[addr=/192.168.1.129,port=44276,localport=4453]
07-19 22:30:20.959: I/clientSocketThread(2843): Current Thread Name: 0
07-19 22:30:20.969: I/Youtube App Request:(2843): GET http://gdata.youtube.com/feeds/api/users/asadfffx/newsubscriptionvideos?format=2%2C3%2C9&start-index=1&max-results=10&safeSearch=none HTTP/1.1
07-19 22:30:20.969: I/Youtube App Request:(2843): GData-Version: 2
07-19 22:30:20.969: I/Youtube App Request:(2843): X-GData-Device: device-id="AOuj_RqmoX-WkCNNaJKieF2mmwMlkOMFRk7sQsKP_wmdrL1BB1N9V_iVIJAUBkvvyzGdpxWVS83wE7UkGPYjWf0BWvbPa0Uoo0cmgKfxzEqOog8EC-Rm1Wg", data="H1NEdDZ+FuL4U9v3Bx1hlVIAm1s="
07-19 22:30:20.969: I/Youtube App Request:(2843): Authorization: GoogleLogin auth="DQAAAKcAAAC5aU6IN0t6yUkoiU9OmjU8fYjKm1m7MLKleHLhtR-uwCclnZGcKGm-6gYfkjvAGKGXK88dbKnB708CVCQkvJofL6smBXp7TEFj1FqGaRasdOx2iVYrbaTbWtIc8sBaga7v2P1BfctMiSTtEU2HWCqqCiubMvpfspnl9wS284SLgk-Se4jjFsZTo-84la_2wJy_Wmap8OSTdif7JoaxpxYLAWECByrJO50iMTj__6cN3A"
07-19 22:30:20.969: I/Youtube App Request:(2843): Host: gdata.youtube.com
07-19 22:30:20.969: I/Youtube App Request:(2843): User-Agent: Android-YouTube/2
07-19 22:30:20.969: I/Youtube App Request:(2843): Proxy-Connection: close
07-19 22:30:20.969: I/Youtube App Request:(2843): Connection: close
07-19 22:30:20.969: I/Youtube App Request:(2843):
07-19 22:30:20.979: I/Connecting to host(2843): gdata.youtube.com
这就是客户端请求的样子。但是当我取消注释以下行时（即它被执行）：
writeToYoutubeServerStream.write(youtubeAppReqArray, 0, bytesRead);
一切都崩溃了。特别是，来自 YouTube 应用程序的请求没有任何意义。创建了数百个线程。我的 GET 请求开始看起来像：
07-19 22:36:21.969: I/Youtube App Request:(2916): GData-Version: 2
07-19 22:36:21.969: I/Youtube App Request:(2916): X-GData-Device: device-id="AOuj_RqmoX-WkCNNaJKieF2mmwMlkOMFRk7sQsKP_wmdrL1BB1N9V_iVIJAUBkvvyzGdpxWVS83wE7UkGPYjWf0BWvbPa0Uoo0cmgKfxzEqOog8EC-Rm1Wg", data="H1NEdDZ+FuL4U9v3Bx1hlVIAm1s="
07-19 22:36:21.969: I/Youtube App Request:(2916): Authorization: GoogleLogin auth="DQAAAKcAAAC5aU6IN0t6yUkoiU9OmjU8fYjKm1m7MLKleHLhtR-uwCclnZGcKGm-6gYfkjvAGKGXK88dbKnB708CVCQkvJofL6smBXp7TEFj1FqGaRasdOx2iVYrbaTbWtIc8sBaga7v2P1BfctMiSTtEU2HWCqqCiubMvpfspnl9wS284SLgk-Se4jjFsZTo-84la_2wJy_Wmap8OSTdif7JoaxpxYLAWECByrJO50iMTj__6cN3A"
07-19 22:36:21.969: I/Youtube App Request:(2916): Host: gdat
07-19 22:36:21.969: I/Connecting to host(2916): gdata.youtube.com
07-19 22:36:21.979: D/SocketServerThread(2916): Client connected : Socket[addr=/192.168.1.129,port=55126,localport=4453]
07-19 22:36:21.979: I/clientSocketThread(2916): Client connected: Socket[addr=/192.168.1.129,port=55125,localport=4453]
07-19 22:36:21.979: I/clientSocketThread(2916): Current Thread Name: 463
07-19 22:36:21.979: I/Youtube App Request:(2916): GET http://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.comhttp://gdata.youtube.com/feeds/api/users/asadfffx/newsubscriptionvideos?format=2%2C3%2C9&start-index=1&max-results=10&safeSearch=none HTTP/1.1
07-19 22:36:21.979: I/Youtube App Request:(2916): GData-Version: 2
07-19 22:36:21.979: I/Youtube App Request:(2916): X-GData-Device: device-id="AOuj_RqmoX-WkCNNaJKieF2mmwMlkOMFRk7sQsKP_wmdrL1BB1N9V_iVIJAUBkvvyzGdpxWVS83wE7UkGPYjWf0BWvbPa0Uoo0cmgKfxzEqOog8EC-Rm1Wg", data="H1NEdDZ+FuL4U9v3Bx1hlVIAm1s="
07-19 22:36:21.979: I/Youtube App Request:(2916): Authorization: GoogleLogin auth="DQAAAKcAAAC5aU6IN0t6yUkoiU9OmjU8fYjKm1m7MLKleHLhtR-uwCclnZGcKGm-6gYfkjvAGKGXK88dbKnB708CVCQkvJofL6smBXp7TEFj1FqGaRasdOx2iVYrbaTbWtIc8sBaga7v2P1BfctMiSTtEU2HWCqqCiubMvpfspnl9wS284SLgk-Se4jjFsZTo-84la_2wJy_Wmap8OSTdif7JoaxpxYLAWECByrJO50iMTj__6cN3A"
07-19 22:36:21.979: I/Youtube App Request:(2916): Host: gdata.youtube.com
为什么 GET 请求看起来像这样？我的猜测是，线程有问题。创建套接字，读/写线程安全吗？代码是否在线程之间跳转？我究竟做错了什么？相同的代码在 Java SE 中工作；那么为什么它在Android中分崩离析？
任何建议、评论和代码片段将不胜感激。
