superlink.java

简单的html解释器

package html_parser;

import java.net.MalformedURLException;
import java.net.URL;

class NotLinkException extends Exception{
	final static long serialVersionUID = 8272;
}
public class SuperLink {
	private URL url;
	String describe;
	public SuperLink(Tag tag, URL currentURL) throws NotLinkException {
		String tagString = tag.toString();
		if (tagString.indexOf("a ") != 0) throw new NotLinkException();
		int index = tagString.indexOf("href");
		if (index == -1) throw new NotLinkException();
		int i1;
		boolean equalBefore = false;
		boolean quoteBefore = false;
		for (i1=index+4;i1<tagString.length();i1++) { 
			if (tagString.charAt(i1) == '=') {
				if (equalBefore) throw new NotLinkException();
				else equalBefore = true;
			} else if (tagString.charAt(i1) == '\"') {
				if (quoteBefore) throw new NotLinkException();
				else quoteBefore = true;
			} else if (tagString.charAt(i1) != ' ') break;
		}
		
		int i2;
		for (i2=i1+1;i2<tagString.length();i2++) { 
			if (tagString.charAt(i2) == ' ' || tagString.charAt(i2) == '\"') break;
		}
		try {
			url = new URL(currentURL, StringTools.stringTransfer(tagString.substring(i1, i2)));
		} catch (MalformedURLException err) {
			throw new NotLinkException();
		}
	}
	public URL getURL() {
		return url;
	}
}