HttpMirror.java Source code

Introduction

Here is the source code for HttpMirror.java

Source

/*
 * Copyright (c) 2004 David Flanagan.  All rights reserved.
 * This code is from the book Java Examples in a Nutshell, 3nd Edition.
 * It is provided AS-IS, WITHOUT ANY WARRANTY either expressed or implied.
 * You may study, use, and modify it for any non-commercial purpose,
 * including teaching and use in open-source projects.
 * You may distribute it non-commercially as long as you retain this notice.
 * For a commercial use license, or to purchase the book, 
 * please visit http://www.davidflanagan.com/javaexamples3.
 */
//package je3.net;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.net.ServerSocket;
import java.net.Socket;

/**
 * This program is a very simple Web server. When it receives a HTTP request it
 * sends the request back as the reply. This can be of interest when you want to
 * see just what a Web client is requesting, or what data is being sent when a
 * form is submitted, for example.
 */
public class HttpMirror {
    public static void main(String args[]) {
        try {
            // Get the port to listen on
            int port = Integer.parseInt(args[0]);
            // Create a ServerSocket to listen on that port.
            ServerSocket ss = new ServerSocket(port);
            // Now enter an infinite loop, waiting for & handling connections.
            for (;;) {
                // Wait for a client to connect. The method will block;
                // when it returns the socket will be connected to the client
                Socket client = ss.accept();

                // Get input and output streams to talk to the client
                BufferedReader in = new BufferedReader(new InputStreamReader(client.getInputStream()));
                PrintWriter out = new PrintWriter(client.getOutputStream());

                // Start sending our reply, using the HTTP 1.1 protocol
                out.print("HTTP/1.1 200 \r\n"); // Version & status code
                out.print("Content-Type: text/plain\r\n"); // The type of data
                out.print("Connection: close\r\n"); // Will close stream
                out.print("\r\n"); // End of headers

                // Now, read the HTTP request from the client, and send it
                // right back to the client as part of the body of our
                // response. The client doesn't disconnect, so we never get
                // an EOF. It does sends an empty line at the end of the
                // headers, though. So when we see the empty line, we stop
                // reading. This means we don't mirror the contents of POST
                // requests, for example. Note that the readLine() method
                // works with Unix, Windows, and Mac line terminators.
                String line;
                while ((line = in.readLine()) != null) {
                    if (line.length() == 0)
                        break;
                    out.print(line + "\r\n");
                }

                // Close socket, breaking the connection to the client, and
                // closing the input and output streams
                out.close(); // Flush and close the output stream
                in.close(); // Close the input stream
                client.close(); // Close the socket itself
            } // Now loop again, waiting for the next connection
        }
        // If anything goes wrong, print an error message
        catch (Exception e) {
            System.err.println(e);
            System.err.println("Usage: java HttpMirror <port>");
        }
    }
}