fetchurlconnection.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 3
public class FetchURLConnection
{
	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 FetchURLConnection 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();

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

			// Display the MIME content-type of the resource (e.g. text/html)
			String MIME = connection.getContentType();
			System.out.println ("Content-type: " + MIME);

			// Display, if available, the content length
			int contentLength = connection.getContentLength();
			if (contentLength != -1)
			{
				System.out.println ("Content-length: " + contentLength);
			}

			// Pause for user
			System.out.println ("Hit enter to continue");
			System.in.read();

			// Read the contents of the resource from the connection
			InputStream in = connection.getInputStream();

			// Buffer the stream, for better performance
			BufferedInputStream bufIn = new BufferedInputStream(in);

			// Repeat until end of file
			for (;;)
			{
				int data = bufIn.read();

				// Check for EOF
				if (data == -1)
					break;
				else
					System.out.print ( (char) data);
			}
		}
		// 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;
		}
	}
}