httpsmessage.java

利用java开发http客户端的程序

// Copyright (C) 2000 by Matt Towers <[e-mail]>.  All rights reserved.
// Use of this class is limited.  Please see the LICENSE for more information.

package com.oreilly.servlet;

import java.io.*;
import java.net.*;
import java.util.*;
import java.security.Security;
import java.security.Provider;

/**
 * A class to simplify HTTP/HTTPS client-server communication.	It abstracts
 * the communication into messages, which can be either GET or POST.
 * <p>
 * It can be used like this:
 * <blockquote><pre>
 * &nbsp;
 * HttpsMessage msg = new HttpsMessage("https://[some server]");
 * &nbsp;
 * Properties props = new Properties();
 * props.put("name", "value");
 * &nbsp;
 * InputStream in = msg.sendGetMessage(props);
 * </pre></blockquote>
 * This class extends the HttpMessage class
 * written by Jason Hunter at servlets.com.
 * The HttpMessage class can be found in the com.oreilly.servlets
 * package found at www.servlets.com
 * 
 * @author <b>Matt Towers</b>
 * @author Copyright &#169; 2000
 * @version 1.0, 2000/05/05
 */
public class HttpsMessage extends com.oreilly.servlet.HttpMessage
{

  //A flag to indicate weather or not the stream handler has been set
  static boolean m_bStreamHandlerSet = false;

  /**
   * Constructs a new HttpsMessage that can be used to communicate with the 
   * servlet at the specified URL using HTTPS.
   *
   * @param szURL the server resource (typically a servlet) with which 
   * to communicate
   */
  public HttpsMessage(String szURL) throws Exception
  {
	super(null);
	//If the stream handler has already been set
	//there is no need to do anything
	if( !m_bStreamHandlerSet )
	{
		String szVendor = System.getProperty("java.vendor");
		String szVersion = System.getProperty("java.version");
		//Assumes a system version string of the form [major].[minor].[release]  (eg. 1.2.2)
		Double dVersion = new Double(szVersion.substring(0, 3));

		//Otherwise, if we are running in a MS environment, use the MS stream handler.
		if( -1 < szVendor.indexOf("Microsoft") )
		{
    		try
    		{
    			Class clsFactory = Class.forName("com.ms.net.wininet.WininetStreamHandlerFactory" );
				if ( null != clsFactory)
					URL.setURLStreamHandlerFactory((URLStreamHandlerFactory)clsFactory.newInstance());
			}
			catch( ClassNotFoundException cfe )
			{
				throw new Exception("Unable to load the Microsoft SSL stream handler.  Check classpath."  + cfe.toString());
			}			
			//If the stream handler factory has already been successfuly set
			//make sure our flag is set and eat the error
			catch( Error err ){m_bStreamHandlerSet = true;}
		}
		//If we are in a normal Java environment, try to use the JSSE handler.
		else if( 1.2 <= dVersion.doubleValue() )
		{
			System.setProperty("java.protocol.handler.pkgs", "com.sun.net.ssl.internal.www.protocol"); 
			try
			{
				//if we have the JSSE provider available, and it has not already been
				//set, add it as a new provide to the Security class.
				Class clsFactory = Class.forName("com.sun.net.ssl.internal.ssl.Provider");
				if( (null != clsFactory) && (null == Security.getProvider("SunJSSE")) )
						Security.addProvider((Provider)clsFactory.newInstance());
			}
			catch( ClassNotFoundException cfe )
			{
				throw new Exception("Unable to load the JSSE SSL stream handler.  Check classpath."  + cfe.toString());
			}
		}
										
		m_bStreamHandlerSet = true;
	}
	
	super.servlet = new URL(szURL);
  }
}