minibrowse.java

一个不错的HTMl语法分析程序

/*
(c) Copyright IBM Corp. 1999 All rights reserved. 

This sample program is owned by International Business Machines Corporation or
one of its subsidiaries ("IBM") and is copyrighted and licensed, not sold. 

You may copy, modify, and distribute this sample program in any form without
payment to IBM, for any purpose including developing, using, marketing or
distributing programs that include or are derivative works of the sample program. 

The sample program is provided to you on an "AS IS" basis, without warranty of
any kind. IBM HEREBY EXPRESSLY DISCLAIMS ALL WARRANTIES, EITHER
EXPRESS OR IMPLIED, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
PURPOSE. Some jurisdictions do not allow for the exclusion or limitation of
implied warranties, so the above limitations or exclusions may not apply to you.
IBM shall not be liable for any damages you suffer as a result of using, modifying
or distributing the sample program or its derivatives. 

Each copy of any portion of this sample program or any derivative work, must
include the above copyright notice and disclaimer of warranty. 
*/
import java.net.*;
import java.io.*;

/*
This is a miniature line-mode browser. It will connect to a URL provided on the command line, and return the 
contents of the page. It is good for testing servlets, as well.

Format: 

java miniBrowse <URL> <raw|cooked>

Raw mode will just dump the HTML datastream back to the screen. Cooked mode does some rudimentary parsing. 
It defaults to "cooked" mode, just to not clutter up the screen as much.

*/
public class miniBrowse
{
	static URL addr = null;
	static String method = null;

	miniBrowse(String pageURL)
	{
		BufferedReader in = null;
		PrintWriter out = new PrintWriter(new BufferedWriter(
							new OutputStreamWriter(
								System.out)));
		try 
		{
			addr = new URL(pageURL);
		}
		catch (MalformedURLException e)
		{
			out.println("Invalid URL.");
			System.exit(4);
		}
		
		try
		{
			URLConnection page = addr.openConnection();
	        	in = new BufferedReader(new InputStreamReader(page.getInputStream()));
			if (method.equalsIgnoreCase("cooked"))
				cookedOutput(in, out);
			else
				rawOutput(in, out);
		}
		catch (Exception e)
		{
		}
	}

	public void cookedOutput(BufferedReader in, PrintWriter out)
	{
		int chr = ' ';
		int pchr = ' ';
		boolean skip = true;
		String tag = "";
		String list = "";
		int lcount = 0;

		try
		{
			while ((chr = in.read()) != -1)
			{
/*
found an HTML tag, let's extract it
*/
				if (chr == '<')
				{
					tag = "";
					while ((chr = in.read()) != '>')
					{
						if (chr == -1)
						{
							out.println("Missing '>'");
							System.exit(8);
						}
						tag = tag + Character.toUpperCase((char)chr);
					}
/* 	
some basic tag processing (default is skip quietly)
notice we skip the entire HEAD section!!
*/

					if (tag.startsWith("BODY"))
						skip = false;
	
					if (tag.equals("BR"))
					{
						out.println("");
					}
	
					if (tag.equals("HR"))
					{
						out.println("\n-------------");
					}
/*
lists, ordered and unordered - new line and indent
each member (ordered list numbers members)
*/
					if (tag.equals("UL") || tag.equals("OL"))
					{
						out.println("");
						list = tag;
						lcount = 0;
					}

					if (tag.equals("LI"))
					{
						if (list.equals("OL"))
							out.print("\n" + ++lcount);
						else
							out.print("\n-- ");
					}

					if (tag.startsWith("A "))
					{
						out.print("<Link>");
					}


					if (tag.startsWith("IMG"))
					{
						out.print("<Image>");
					}

					if (tag.startsWith("APPLET"))
					{
						out.print("<Java>");
					}


					if (tag.startsWith("SCRIPT"))
					{
						out.print("<JavaScript>");
					}

					if (tag.equals("P"))
					{
						out.println("\n\n");
					}
					continue;
				}

				if (!skip)
				{
/*
don't echo excess spaces
*/
					if (chr != ' ')
						out.write(chr);
					else
						if (pchr != ' ')
							out.write(chr);
					pchr = chr;
				}
			}	
			out.flush();
		}
		catch (IOException e)
		{
			out.println("I/O Exception.");
		}
	}	

	public void rawOutput(BufferedReader in, PrintWriter out)
	{
		String inputLine;
		try 
		{
			while ((inputLine = in.readLine()) != null) 
				out.println(inputLine);
		}
		catch (IOException e)
		{
			out.println("I/O Exception.");
		}
		out.flush();
	}

	public static void main(String[] args)
	{
		if (args.length > 1)
			method = args[1];
		else
			method = "cooked";

		if (args.length > 0)
			new miniBrowse(args[0]);
	}
}