UriRetriever.java Accepts a host, port, and file from the command line and retrieves the implied URL from the HTTP server by issuing a GET request. Uses the following classes: #Programming Code Examples #NULL #Network Programming

UriRetriever.java  Accepts a host, port, and file from the command line and retrieves the implied URL from the HTTP server by issuing a GET request. Uses the following classes:


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

/** Retrieve a URL given the host, port, and file as three
 *  separate command-line arguments. A later class
 *  (UrlRetriever) supports a single URL instead.
 *
 *  Taken from Core Web Programming from
 *  Prentice Hall and Sun Microsystems Press,
 *  .
 *  © 2001 Marty Hall and Larry Brown;
 *  may be freely used or adapted.
 */

public class UriRetriever extends NetworkClient {
  private String uri;

  public static void main(String[] args) {
    UriRetriever uriClient
      = new UriRetriever(args[0], Integer.parseInt(args[1]),
                         args[2]);
    uriClient.connect();
  }

  public UriRetriever(String host, int port, String uri) {
    super(host, port);
    this.uri = uri;
  }

  /** Send one GET line, then read the results one line at a
   *  time, printing each to standard output.
   */

  // It is safe to use blocking IO (readLine), since
  // HTTP servers close connection when done, resulting
  // in a null value for readLine.

  protected void handleConnection(Socket uriSocket)
      throws IOException {
    PrintWriter out = SocketUtil.getWriter(uriSocket);
    BufferedReader in = SocketUtil.getReader(uriSocket);
    out.println("GET " + uri + " HTTP/1.0rn");
    String line;
    while ((line = in.readLine()) != null) {
      System.out.println("> " + line);
    }
  }
}


NetworkClient.java  Starting point for a network client to communicate with a remote computer

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

/** A starting point for network clients. You'll need to
 *  override handleConnection, but in many cases connect can
 *  remain unchanged. It uses SocketUtil to simplify the
 *  creation of the PrintWriter and BufferedReader.
 *
 *  Taken from Core Web Programming from
 *  Prentice Hall and Sun Microsystems Press,
 *  .
 *  © 2001 Marty Hall and Larry Brown;
 *  may be freely used or adapted.
 */

public class NetworkClient {
  protected String host;
  protected int port;

  /** Register host and port. The connection won't
   *  actually be established until you call
   *  connect.
   */

  public NetworkClient(String host, int port) {
    this.host = host;
    this.port = port;
  }

  /** Establishes the connection, then passes the socket
   *  to handleConnection.
   */

  public void connect() {
    try {
      Socket client = new Socket(host, port);
      handleConnection(client);
    } catch(UnknownHostException uhe) {
      System.out.println("Unknown host: " + host);
      uhe.printStackTrace();
    } catch(IOException ioe) {
      System.out.println("IOException: " + ioe);
      ioe.printStackTrace();
    }
  }

  /** This is the method you will override when
   *  making a network client for your task.
   *  The default version sends a single line
   *  ("Generic Network Client") to the server,
   *  reads one line of response, prints it, then exits.
   */

  protected void handleConnection(Socket client)
    throws IOException {
    PrintWriter out = SocketUtil.getWriter(client);
    BufferedReader in = SocketUtil.getReader(client);
    out.println("Generic Network Client");
    System.out.println
      ("Generic Network Client:n" +
       "Made connection to " + host +
       " and got '" + in.readLine() + "' in response");
    client.close();
  }

  /** The hostname of the server we're contacting. */

  public String getHost() {
    return(host);
  }

  /** The port connection will be made on. */

  public int getPort() {
    return(port);
  }
}

SocketUtil.java  Provides utilities for wrapping a BufferedReader  and PrintWriter around the Socket's input and output streams, respectively. 

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

/** A shorthand way to create BufferedReaders and
 *  PrintWriters associated with a Socket.
 *
 *  Taken from Core Web Programming from
 *  Prentice Hall and Sun Microsystems Press,
 *  .
 *  © 2001 Marty Hall and Larry Brown;
 *  may be freely used or adapted.
 */

public class SocketUtil {
  /** Make a BufferedReader to get incoming data. */

  public static BufferedReader getReader(Socket s)
      throws IOException {
    return(new BufferedReader(
       new InputStreamReader(s.getInputStream())));
  }

  /** Make a PrintWriter to send outgoing data.
   *  This PrintWriter will automatically flush stream
   *  when println is called.
   */

  public static PrintWriter getWriter(Socket s)
      throws IOException {
    // Second argument of true means autoflush.
    return(new PrintWriter(s.getOutputStream(), true));
  }
}

Note: Brought from our old site: http://www.salearningschool.com/example_codes/ on Jan 2nd, 2017 From: http://sitestree.com/?p=10230
Categories:Programming Code Examples, NULL, Network Programming
Tags:NULLNetwork Programming
Post Data:2017-01-02 16:04:28

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