www.pudn.com > jnp-src.rar > HTTPURLConnection.java

/*
 * Java Network Programming, Second Edition
 * Merlin Hughes, Michael Shoffner, Derek Hamner
 * Manning Publications Company; ISBN 188477749X
 *
 * http://nitric.com/jnp/
 *
 * Copyright (c) 1997-1999 Merlin Hughes, Michael Shoffner, Derek Hamner;
 * all rights reserved; see license.txt for details.
 */

import java.io.*; 
import java.net.*; 
import java.util.*; 
import java.text.*; 
 
public class HTTPURLConnection extends URLConnection { 
  protected Hashtable requestProperties; 
  protected Vector keys; 
  protected Hashtable headers; 
   
  public HTTPURLConnection (URL url) { 
    super (url); 
    requestProperties = new Hashtable (); 
    keys = new Vector (); 
    headers = new Hashtable (); 
  } 
 
  public void setRequestProperty (String name, String value) { 
    if (connected) 
      throw new IllegalStateException ("Already connected."); 
    requestProperties.put (name, value); 
  } 
 
  public String getRequestProperty (String name) { 
    return (String) requestProperties.get (name); 
  } 
 
  protected InputStream in; 
   
  public synchronized void connect () throws IOException { 
    if (!connected) { 
      String host = url.getHost (); 
      int port = (url.getPort () == -1) ? 80 : url.getPort (); 
      Socket socket = new Socket (host, port); 
      sendRequest (socket.getOutputStream ()); 
      in = new BufferedInputStream (socket.getInputStream ()); 
      readHeaders (); 
      connected = true; 
    } 
  } 
 
  protected void sendRequest (OutputStream out) throws IOException { 
    setRequestProperty ("User-Agent", "JNP-HTTP/2e"); 
    if (ifModifiedSince != 0) { 
      Date since = new Date (ifModifiedSince); 
      SimpleDateFormat formatter = 
        new SimpleDateFormat ("EEE, d MMM yyyy hh:mm:ss z"); 
      formatter.setTimeZone (TimeZone.getTimeZone ("GMT")); 
      setRequestProperty ("If-Modified-Since", formatter.format (since)); 
    } 
    StringBuffer request = new StringBuffer ("GET "); 
    request.append (URLEncoder.encode (url.getFile ())); 
    request.append (" HTTP/1.0\r\n"); 
    Enumeration keys = requestProperties.keys (); 
    while (keys.hasMoreElements ()) { 
      String key = (String) keys.nextElement (); 
      request.append (key); 
      request.append (": "); 
      request.append (requestProperties.get (key)); 
      request.append ("\r\n"); 
    } 
    request.append ('\n'); 
    out.write (request.toString ().getBytes ("latin1")); 
  } 
 
  protected void readHeaders () throws IOException { 
    String status = readLine (); 
    String header; 
    while (((header = readLine ()) != null) && 
           (!header.trim ().equals (""))) { 
      int colon = header.indexOf (":"); 
      if (colon >= 0) { 
        String key = header.substring (0, colon).trim (); 
        String value = header.substring (colon + 1).trim (); 
        keys.addElement (key); 
        headers.put (key.toLowerCase (), value); 
      } 
    } 
  } 
 
  protected String readLine () throws IOException { 
    StringBuffer result = new StringBuffer (); 
    int chr; 
    while (((chr = in.read ()) != -1) && (chr != 10) && (chr != 13)) 
      result.append ((char) chr); 
    if ((chr == -1) && (result.length () == 0)) 
      return null; 
    if (chr == 13) { 
      in.mark (1); 
      if (in.read () != 10) 
        in.reset (); 
    } 
    return result.toString (); 
  } 
 
  public InputStream getInputStream () throws IOException { 
    if (!doInput) 
      throw new IllegalStateException ("Input disabled."); 
    connect (); 
    return in; 
  } 
 
  public String getHeaderFieldKey (int index) { 
    if (!connected) 
      throw new IllegalStateException ("Not connected."); 
    if (index < keys.size ()) 
      return (String) keys.elementAt (index); 
    else 
      return null; 
  } 
 
  public String getHeaderField (int index) { 
    if (!connected) 
      throw new IllegalStateException ("Not connected."); 
    if (index < keys.size ()) 
      return getHeaderField ((String) keys.elementAt (index)); 
    else 
      return null; 
  } 
 
  public String getHeaderField (String key) { 
    if (!connected) 
      throw new IllegalStateException ("Not connected."); 
    return (String) headers.get (key.toLowerCase ()); 
  } 
}