httpheaders.java

Java网络编程与分布式计算, 主要分析java网络各方面的编程, 提供许多实用安全

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

// Chapter 9, Listing 4
public class HTTPHeaders
{
	public static void main(String args[]) throws Exception
	{
		int argc = args.length;

		// Check for valid number of parameters
		if (argc != 1)
		{
			System.out.println ("Syntax :");
			System.out.println ("java HTTPHeaders url");
			return;
		}

		// Catch any thrown exceptions
		try
		{
			// Create an instance of java.net.URL
			java.net.URL myURL = new URL ( args[0] );

			// Create a URLConnection object, for this URL
			// NOTE : no connection has yet been established
			URLConnection connection = myURL.openConnection();

			// Set some basic request fields

			// Set user agent, to identify the application as Netscape compatible
			connection.setRequestProperty ("User-Agent", "Mozilla/4.0 (compatible; JavaApp)");

			// Set our referer field - set to any URL you'd like
			connection.setRequestProperty ("Referer", "http://www.davidreilly.com/");

			// Set use-caches field, to prevent caching
			connection.setUseCaches(false);

			// Now open a connection
			connection.connect();

			// Examine request properties, to verify their settings
			System.out.println ("Request properties...."); System.out.println();
			System.out.println ("User-Agent: " + connection.getRequestProperty("User-Agent"));
			System.out.println ("Referer: " + connection.getRequestProperty("Referer"));
			System.out.println (); System.out.println ();

			// Examine response properties, to see their settings
			System.out.println ("Response properties...."); System.out.println();

			int i = 1;

			// Search through each header field, until no more exist
			while ( connection.getHeaderField ( i ) != null )
			{
				// Get the name of this header field
				String headerName = connection.getHeaderFieldKey(i);

				// Get the name of this header field
				String headerValue = connection.getHeaderField(i);

				// Output header field key, and header field value
				System.out.println ( headerName + ": " + headerValue);				

				// Goto the next element in the set of header fields
				i++;
			}
			
			// Pause for user
			System.out.println ("Hit enter to continue");
			System.in.read();			
		}
		// MalformedURLException indicates parsing error
		catch (MalformedURLException mue)
		{
			System.err.println ("Unable to parse URL!");
			return;
		}
		// IOException indicates network or I/O error
		catch (IOException ioe)
		{
			System.err.println ("I/O Error : " + ioe);
			return;
		}
	}
}