我正在编写一个java应用程序作为本地代理。来自http://www.nsftools.com/tips/jProxy.java的这段代码给了我很大的帮助。见下面的程序：
/* <!-- in case someone opens this in a browser... --> <pre> */
/*
* This is a simple multi-threaded Java proxy server
* for HTTP requests (HTTPS doesn't seem to work, because
* the CONNECT requests aren't always handled properly).
* I implemented the class as a thread so you can call it
* from other programs and kill it, if necessary (by using
* the closeSocket() method).
*
* We'll call this the 1.1 version of this class. All I
* changed was to separate the HTTP header elements with
* \r\n instead of just \n, to comply with the official
* HTTP specification.
*
* This can be used either as a direct proxy to other
* servers, or as a forwarding proxy to another proxy
* server. This makes it useful if you want to monitor
* traffic going to and from a proxy server (for example,
* you can run this on your local machine and set the
* fwdServer and fwdPort to a real proxy server, and then
* tell your browser to use "localhost" as the proxy, and
* you can watch the browser traffic going in and out).
*
* One limitation of this implementation is that it doesn't
* close the ProxyThread socket if the client disconnects
* or the server never responds, so you could end up with
* a bunch of loose threads running amuck and waiting for
* connections. As a band-aid, you can set the server socket
* to timeout after a certain amount of time (use the
* setTimeout() method in the ProxyThread class), although
* this can cause false timeouts if a remote server is simply
* slow to respond.
*
* Another thing is that it doesn't limit the number of
* socket threads it will create, so if you use this on a
* really busy machine that processed a bunch of requests,
* you may have problems. You should use thread pools if
* you're going to try something like this in a "real"
* application.
*
* Note that if you're using the "main" method to run this
* by itself and you don't need the debug output, it will
* run a bit faster if you pipe the std output to 'nul'.
*
* You may use this code as you wish, just don't pretend
* that you wrote it yourself, and don't hold me liable for
* anything that it does or doesn't do. If you're feeling
* especially honest, please include a link to nsftools.com
* along with the code. Thanks, and good luck.
*
* Julian Robichaux -- http://www.nsftools.com
*/
import java.io.*;
import java.net.*;
import java.lang.reflect.Array;
public class jProxy extends Thread
{
public static final int DEFAULT_PORT = 8080;
private ServerSocket server = null;
private int thisPort = DEFAULT_PORT;
private String fwdServer = "";
private int fwdPort = 0;
private int ptTimeout = ProxyThread.DEFAULT_TIMEOUT;
private int debugLevel = 0;
private PrintStream debugOut = System.out;
/* here's a main method, in case you want to run this by itself */
public static void main (String args[])
{
int port = 0;
String fwdProxyServer = "";
int fwdProxyPort = 0;
if (args.length == 0)
{
System.err.println("USAGE: java jProxy <port number> [<fwd proxy> <fwd port>]");
System.err.println(" <port number> the port this service listens on");
System.err.println(" <fwd proxy> optional proxy server to forward requests to");
System.err.println(" <fwd port> the port that the optional proxy server is on");
System.err.println("\nHINT: if you don't want to see all the debug information flying by,");
System.err.println("you can pipe the output to a file or to 'nul' using \">\". For example:");
System.err.println(" to send output to the file prox.txt: java jProxy 8080 > prox.txt");
System.err.println(" to make the output go away: java jProxy 8080 > nul");
return;
}
// get the command-line parameters
port = Integer.parseInt(args[0]);
if (args.length > 2)
{
fwdProxyServer = args[1];
fwdProxyPort = Integer.parseInt(args[2]);
}
// create and start the jProxy thread, using a 20 second timeout
// value to keep the threads from piling up too much
System.err.println(" ** Starting jProxy on port " + port + ". Press CTRL-C to end. **\n");
jProxy jp = new jProxy(port, fwdProxyServer, fwdProxyPort, 20);
jp.setDebug(1, System.out); // or set the debug level to 2 for tons of output
jp.start();
// run forever; if you were calling this class from another
// program and you wanted to stop the jProxy thread at some
// point, you could write a loop that waits for a certain
// condition and then calls jProxy.closeSocket() to kill
// the running jProxy thread
while (true)
{
try { Thread.sleep(3000); } catch (Exception e) {}
}
// if we ever had a condition that stopped the loop above,
// we'd want to do this to kill the running thread
//jp.closeSocket();
//return;
}
/* the proxy server just listens for connections and creates
* a new thread for each connection attempt (the ProxyThread
* class really does all the work)
*/
public jProxy (int port)
{
thisPort = port;
}
public jProxy (int port, String proxyServer, int proxyPort)
{
thisPort = port;
fwdServer = proxyServer;
fwdPort = proxyPort;
}
public jProxy (int port, String proxyServer, int proxyPort, int timeout)
{
thisPort = port;
fwdServer = proxyServer;
fwdPort = proxyPort;
ptTimeout = timeout;
}
/* allow the user to decide whether or not to send debug
* output to the console or some other PrintStream
*/
public void setDebug (int level, PrintStream out)
{
debugLevel = level;
debugOut = out;
}
/* get the port that we're supposed to be listening on
*/
public int getPort ()
{
return thisPort;
}
/* return whether or not the socket is currently open
*/
public boolean isRunning ()
{
if (server == null)
return false;
else
return true;
}
/* closeSocket will close the open ServerSocket; use this
* to halt a running jProxy thread
*/
public void closeSocket ()
{
try {
// close the open server socket
server.close();
// send it a message to make it stop waiting immediately
// (not really necessary)
/*Socket s = new Socket("localhost", thisPort);
OutputStream os = s.getOutputStream();
os.write((byte)0);
os.close();
s.close();*/
} catch(Exception e) {
if (debugLevel > 0)
debugOut.println(e);
}
server = null;
}
public void run()
{
try {
// create a server socket, and loop forever listening for
// client connections
server = new ServerSocket(thisPort);
if (debugLevel > 0)
debugOut.println("Started jProxy on port " + thisPort);
while (true)
{
Socket client = server.accept();
ProxyThread t = new ProxyThread(client, fwdServer, fwdPort);
t.setDebug(debugLevel, debugOut);
t.setTimeout(ptTimeout);
t.start();
}
} catch (Exception e) {
if (debugLevel > 0)
debugOut.println("jProxy Thread error: " + e);
}
closeSocket();
}
}
/*
* The ProxyThread will take an HTTP request from the client
* socket and send it to either the server that the client is
* trying to contact, or another proxy server
*/
class ProxyThread extends Thread
{
private Socket pSocket;
private String fwdServer = "";
private int fwdPort = 0;
private int debugLevel = 0;
private PrintStream debugOut = System.out;
// the socketTimeout is used to time out the connection to
// the remote server after a certain period of inactivity;
// the value is in milliseconds -- use zero if you don't want
// a timeout
public static final int DEFAULT_TIMEOUT = 20 * 1000;
private int socketTimeout = DEFAULT_TIMEOUT;
public ProxyThread(Socket s)
{
pSocket = s;
}
public ProxyThread(Socket s, String proxy, int port)
{
pSocket = s;
fwdServer = proxy;
fwdPort = port;
}
public void setTimeout (int timeout)
{
// assume that the user will pass the timeout value
// in seconds (because that's just more intuitive)
socketTimeout = timeout * 1000;
}
public void setDebug (int level, PrintStream out)
{
debugLevel = level;
debugOut = out;
}
public void run()
{
try
{
long startTime = System.currentTimeMillis();
// client streams (make sure you're using streams that use
// byte arrays, so things like GIF and JPEG files and file
// downloads will transfer properly)
BufferedInputStream clientIn = new BufferedInputStream(pSocket.getInputStream());
BufferedOutputStream clientOut = new BufferedOutputStream(pSocket.getOutputStream());
// the socket to the remote server
Socket server = null;
// other variables
byte[] request = null;
byte[] response = null;
int requestLength = 0;
int responseLength = 0;
int pos = -1;
StringBuffer host = new StringBuffer("");
String hostName = "";
int hostPort = 80;
// get the header info (the web browser won't disconnect after
// it's sent a request, so make sure the waitForDisconnect
// parameter is false)
request = getHTTPData(clientIn, host, false);
requestLength = Array.getLength(request);
// separate the host name from the host port, if necessary
// (like if it's "servername:8000")
hostName = host.toString();
pos = hostName.indexOf(":");
if (pos > 0)
{
try { hostPort = Integer.parseInt(hostName.substring(pos + 1));
} catch (Exception e) { }
hostName = hostName.substring(0, pos);
}
// either forward this request to another proxy server or
// send it straight to the Host
try
{
if ((fwdServer.length() > 0) && (fwdPort > 0))
{
server = new Socket(fwdServer, fwdPort);
} else {
server = new Socket(hostName, hostPort);
}
} catch (Exception e) {
// tell the client there was an error
String errMsg = "HTTP/1.0 500\nContent Type: text/plain\n\n" +
"Error connecting to the server:\n" + e + "\n";
clientOut.write(errMsg.getBytes(), 0, errMsg.length());
}
if (server != null)
{
server.setSoTimeout(socketTimeout);
BufferedInputStream serverIn = new BufferedInputStream(server.getInputStream());
BufferedOutputStream serverOut = new BufferedOutputStream(server.getOutputStream());
// send the request out
serverOut.write(request, 0, requestLength);
serverOut.flush();
// and get the response; if we're not at a debug level that
// requires us to return the data in the response, just stream
// it back to the client to save ourselves from having to
// create and destroy an unnecessary byte array. Also, we
// should set the waitForDisconnect parameter to 'true',
// because some servers (like Google) don't always set the
// Content-Length header field, so we have to listen until
// they decide to disconnect (or the connection times out).
if (debugLevel > 1)
{
response = getHTTPData(serverIn, true);
responseLength = Array.getLength(response);
} else {
responseLength = streamHTTPData(serverIn, clientOut, true);
}
serverIn.close();
serverOut.close();
}
// send the response back to the client, if we haven't already
if (debugLevel > 1)
clientOut.write(response, 0, responseLength);
// if the user wants debug info, send them debug info; however,
// keep in mind that because we're using threads, the output won't
// necessarily be synchronous
if (debugLevel > 0)
{
long endTime = System.currentTimeMillis();
debugOut.println("Request from " + pSocket.getInetAddress().getHostAddress() +
" on Port " + pSocket.getLocalPort() +
" to host " + hostName + ":" + hostPort +
"\n (" + requestLength + " bytes sent, " +
responseLength + " bytes returned, " +
Long.toString(endTime - startTime) + " ms elapsed)");
debugOut.flush();
}
if (debugLevel > 1)
{
debugOut.println("REQUEST:\n" + (new String(request)));
debugOut.println("RESPONSE:\n" + (new String(response)));
debugOut.flush();
}
// close all the client streams so we can listen again
clientOut.close();
clientIn.close();
pSocket.close();
} catch (Exception e) {
if (debugLevel > 0)
debugOut.println("Error in ProxyThread: " + e);
//e.printStackTrace();
}
}
private byte[] getHTTPData (InputStream in, boolean waitForDisconnect)
{
// get the HTTP data from an InputStream, and return it as
// a byte array
// the waitForDisconnect parameter tells us what to do in case
// the HTTP header doesn't specify the Content-Length of the
// transmission
StringBuffer foo = new StringBuffer("");
return getHTTPData(in, foo, waitForDisconnect);
}
private byte[] getHTTPData (InputStream in, StringBuffer host, boolean waitForDisconnect)
{
// get the HTTP data from an InputStream, and return it as
// a byte array, and also return the Host entry in the header,
// if it's specified -- note that we have to use a StringBuffer
// for the 'host' variable, because a String won't return any
// information when it's used as a parameter like that
ByteArrayOutputStream bs = new ByteArrayOutputStream();
streamHTTPData(in, bs, host, waitForDisconnect);
return bs.toByteArray();
}
private int streamHTTPData (InputStream in, OutputStream out, boolean waitForDisconnect)
{
StringBuffer foo = new StringBuffer("");
return streamHTTPData(in, out, foo, waitForDisconnect);
}
private int streamHTTPData (InputStream in, OutputStream out,
StringBuffer host, boolean waitForDisconnect)
{
// get the HTTP data from an InputStream, and send it to
// the designated OutputStream
StringBuffer header = new StringBuffer("");
String data = "";
int responseCode = 200;
int contentLength = 0;
int pos = -1;
int byteCount = 0;
try
{
// get the first line of the header, so we know the response code
data = readLine(in);
if (data != null)
{
header.append(data + "\r\n");
pos = data.indexOf(" ");
if ((data.toLowerCase().startsWith("http")) &&
(pos >= 0) && (data.indexOf(" ", pos+1) >= 0))
{
String rcString = data.substring(pos+1, data.indexOf(" ", pos+1));
try
{
responseCode = Integer.parseInt(rcString);
} catch (Exception e) {
if (debugLevel > 0)
debugOut.println("Error parsing response code " + rcString);
}
}
}
// get the rest of the header info
while ((data = readLine(in)) != null)
{
// the header ends at the first blank line
if (data.length() == 0)
break;
header.append(data + "\r\n");
// check for the Host header
pos = data.toLowerCase().indexOf("host:");
if (pos >= 0)
{
host.setLength(0);
host.append(data.substring(pos + 5).trim());
}
// check for the Content-Length header
pos = data.toLowerCase().indexOf("content-length:");
if (pos >= 0)
contentLength = Integer.parseInt(data.substring(pos + 15).trim());
}
// add a blank line to terminate the header info
header.append("\r\n");
// convert the header to a byte array, and write it to our stream
out.write(header.toString().getBytes(), 0, header.length());
// if the header indicated that this was not a 200 response,
// just return what we've got if there is no Content-Length,
// because we may not be getting anything else
if ((responseCode != 200) && (contentLength == 0))
{
out.flush();
return header.length();
}
// get the body, if any; we try to use the Content-Length header to
// determine how much data we're supposed to be getting, because
// sometimes the client/server won't disconnect after sending us
// information...
if (contentLength > 0)
waitForDisconnect = false;
if ((contentLength > 0) || (waitForDisconnect))
{
try {
byte[] buf = new byte[4096];
int bytesIn = 0;
while ( ((byteCount < contentLength) || (waitForDisconnect))
&& ((bytesIn = in.read(buf)) >= 0) )
{
out.write(buf, 0, bytesIn);
byteCount += bytesIn;
}
} catch (Exception e) {
String errMsg = "Error getting HTTP body: " + e;
if (debugLevel > 0)
debugOut.println(errMsg);
//bs.write(errMsg.getBytes(), 0, errMsg.length());
}
}
} catch (Exception e) {
if (debugLevel > 0)
debugOut.println("Error getting HTTP data: " + e);
}
//flush the OutputStream and return
try { out.flush(); } catch (Exception e) {}
return (header.length() + byteCount);
}
private String readLine (InputStream in)
{
// reads a line of text from an InputStream
StringBuffer data = new StringBuffer("");
int c;
try
{
// if we have nothing to read, just return null
in.mark(1);
if (in.read() == -1)
return null;
else
in.reset();
while ((c = in.read()) >= 0)
{
// check for an end-of-line character
if ((c == 0) || (c == 10) || (c == 13))
break;
else
data.append((char)c);
}
// deal with the case where the end-of-line terminator is \r\n
if (c == 13)
{
in.mark(1);
if (in.read() != 10)
in.reset();
}
} catch (Exception e) {
if (debugLevel > 0)
debugOut.println("Error getting header: " + e);
}
// and return what we have
return data.toString();
}
}
问题是安全网站，例如＆＃34; https://www.google.com＆＃34;不工作。我试图一遍又一遍地调整代码，但都无济于事。我已经解决了这里回答的问题和更多的网站，但我似乎无法让它工作。我会发布链接，但我不能因为我还没有获得声誉。
有人请帮助我了解支持安全网站（HTTPS）需要做些什么。
提前致谢。
PS：对不起，如果我没有以正确的方式提出问题。我是新手。干杯...
答案 0 :(得分：0)
https的默认端口为443。如果URL中未指定端口，则使用此方法，例如您提供的Google网站的情况。请记住调整代码。