httpclient.java

实现网络客户端、单/多线程网络服务器的功能Exercise 1 of SSD 8

import java.io.*;
import java.net.*;

/**
 * Class <em>HttpClient</em> is a class representing a simple
 * HTTP client.
 *
 * @author iCarnegie, Inc (CTE)
 * @version 1.0
 */

public class HttpClient
{

    /**
     * default HTTP port is port 8000
     */
    private static int port = 8000;

    /**
     * Allow a maximum buffer size of 192 bytes
     */
    private static int buffer_size = 8192;

    /**
     * Response is stored in a byte array.
     */
    private byte[] buffer;

    /**
     * My socket to the world.
     */
    Socket socket = null;

    /**
     * Default port is 8000.
     */
    private static final int PORT = 8000;

    /**
     * Output stream to the socket.
     */
    BufferedOutputStream ostream = null;

    /**
     * Input stream from the socket.
     */
    BufferedInputStream istream = null;

    /**
     * StringBuffer storing the header
     */
    private StringBuffer header = null;

    /**
     * StringBuffer storing the response.
     */
    private StringBuffer response = null;


    /**
     * HttpClient constructor;
     */
    public HttpClient() {
	buffer = new byte[buffer_size];
	header = new StringBuffer();
	response = new StringBuffer();
    }


    /**
     * <em>connect</em> connects to the input host on the default http port --
     * port 80.  This function opens the socket and creates the
     * input and output streams used for communication.
     */
    public void connect( String host ) throws Exception {

	/**
	 * Open my socket to the specified host at
	 * the default port.
	 */
	socket = new Socket(host, PORT);

	/**
	 * Create the output stream.
	 */
	ostream =  new BufferedOutputStream(socket.getOutputStream());

	/**
	 * Create the input stream.
	 */
	istream = new BufferedInputStream(socket.getInputStream());
    }

    /**
     * <em>processGetRequest</em> process the input GET request.
     */
    public void processGetRequest( String request ) throws Exception {

	int last,c;
	/**
	 * Send the request to the server.
	 */
	buffer = request.getBytes();
	ostream.write(buffer, 0, request.length());
	ostream.flush();

	/**
	 * Process the header and add it to the header
	 * StringBuffer.
	 */
	last = 0;
	boolean inHeader = true; // loop control
	c = 0;
	while(inHeader && ((c = istream.read()) != -1)) {
		switch (c) {
		case '\r':
		    break;
		case '\n':
		    if (c == last) {
			inHeader = false;
			break;
		    }
		    last = c;
		    header.append("\n");
		    break;
		default:
		    last = c;
		    header.append((char) c);
		}
	    }

	/**
	 * Read the contents and add it to the response StringBuffer.
	 */
	while(istream.read(buffer) != -1) {
	    response.append( new String(buffer) );
	}
    }

    /**
     * Get the response header.
     */
    public String getHeader() {
	return header.toString();
    }

    /**
     * Get the server's response.
     */
    public String getResponse() {
	return response.toString();
    }

    /**
     * Close all open connections -- sockets and streams.
     */
    public void close() throws Exception {
	socket.close();
	istream.close();
	ostream.close();
    }
}