Java Reference
In-Depth Information
Example 5•6: SimpleProxyServer.java (continued)
while(true) {
// Variables to hold the sockets to the client and to the server.
Socket client = null, server = null;
try {
// Wait for a connection on the local port
client = ss.accept();
// Get client streams. Make them final so they can
// be used in the anonymous thread below.
final InputStream from_client = client.getInputStream();
final OutputStream to_client = client.getOutputStream();
// Make a connection to the real server.
// If we cannot connect to the server, send an error to the
// client, disconnect, and continue waiting for connections.
try { server = new Socket(host, remoteport); }
catch (IOException e) {
PrintWriter out = new PrintWriter(to_client);
out.print("Proxy server cannot connect to " + host + ":"+
remoteport + ":\n" + e + "\n");
out.flush();
client.close();
continue;
}
// Get server streams.
final InputStream from_server = server.getInputStream();
final OutputStream to_server = server.getOutputStream();
// Make a thread to read the client's requests and pass them
// to the server. We have to use a separate thread because
// requests and responses may be asynchronous.
Thread t = new Thread() {
public void run() {
int bytes_read;
try {
while((bytes_read=from_client.read(request))!=-1) {
to_server.write(request, 0, bytes_read);
to_server.flush();
}
}
catch (IOException e) {}
// the client closed the connection to us, so close our
// connection to the server. This will also cause the
// server-to-client loop in the main thread exit.
try {to_server.close();} catch (IOException e) {}
}
};
// Start the client-to-server request thread running
t.start();
// Meanwhile, in the main thread, read the server's responses
// and pass them back to the client. This will be done in
// parallel with the client-to-server request thread above.
int bytes_read;
try {
