HrefMatch.java Source code

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Here is the source code for HrefMatch.java

Source

/*
   This program is a part of the companion code for Core Java 8th ed.
   (http://horstmann.com/corejava)
    
   This program is free software: you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation, either version 3 of the License, or
   (at your option) any later version.
    
   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.
    
   You should have received a copy of the GNU General Public License
   along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

import java.io.IOException;
import java.io.InputStreamReader;
import java.net.URL;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
import java.util.regex.PatternSyntaxException;

/**
 * This program displays all URLs in a web page by matching a regular expression that describes the
 * <a href=...> HTML tag. Start the program as <br>
 * java HrefMatch URL
 * @version 1.01 2004-06-04
 * @author Cay Horstmann
 */
public class HrefMatch {
    public static void main(String[] args) {
        try {
            // get URL string from command line or use default
            String urlString;
            if (args.length > 0)
                urlString = args[0];
            else
                urlString = "http://java.sun.com";

            // open reader for URL
            InputStreamReader in = new InputStreamReader(new URL(urlString).openStream());

            // read contents into string builder
            StringBuilder input = new StringBuilder();
            int ch;
            while ((ch = in.read()) != -1)
                input.append((char) ch);

            // search for all occurrences of pattern
            String patternString = "<a\\s+href\\s*=\\s*(\"[^\"]*\"|[^\\s>]*)\\s*>";
            Pattern pattern = Pattern.compile(patternString, Pattern.CASE_INSENSITIVE);
            Matcher matcher = pattern.matcher(input);

            while (matcher.find()) {
                int start = matcher.start();
                int end = matcher.end();
                String match = input.substring(start, end);
                System.out.println(match);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } catch (PatternSyntaxException e) {
            e.printStackTrace();
        }
    }
}