Javaは正規表現でウェブページの内容をどのように読み取りますか？

package com.xiaofeng.picup;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
/** *//**
*
* @           （  ）         ，                 
*
*/
public class WebContent ...{
  /** *//**
   *           
   */
  public String getOneHtml(String htmlurl) throws IOException...{
    URL url;
    String temp;
    StringBuffer sb = new StringBuffer();
    try ...{
      url = new URL(htmlurl);
      BufferedReader in = new BufferedReader(new InputStreamReader(url
          .openStream(), "utf-8"));//         
      while ((temp = in.readLine()) != null) ...{
        sb.append(temp);
      }
      in.close();
    }catch(MalformedURLException me)...{
      System.out.println("    URL     ！     ");
      me.getMessage();
      throw me;
    }catch (IOException e) ...{
      e.printStackTrace();
      throw e;
    }
    return sb.toString();
  }
  /** *//**
   *
   * @param s
   * @return       
   */
  public String getTitle(String s) ...{
    String regex;
    String title = "";
    List<String> list = new ArrayList<String>();
    regex = "<title>.*?</title>";
    Pattern pa = Pattern.compile(regex, Pattern.CANON_EQ);
    Matcher ma = pa.matcher(s);
    while (ma.find()) ...{
      list.add(ma.group());
    }
    for (int i = 0; i < list.size(); i++) ...{
      title = title + list.get(i);
    }
    return outTag(title);
  }
  /** *//**
   *
   * @param s
   * @return     
   */
  public List<String> getLink(String s) ...{
    String regex;
    List<String> list = new ArrayList<String>();
    regex = "<a[^>]*href=("([^"]*)"|'([^']*)'|([^s>]*))[^>]*>(.*?)</a>";
    Pattern pa = Pattern.compile(regex, Pattern.DOTALL);
    Matcher ma = pa.matcher(s);
    while (ma.find()) ...{
      list.add(ma.group());
    }
    return list;
  }
  /** *//**
   *
   * @param s
   * @return       
   */
  public List<String> getScript(String s) ...{
    String regex;
    List<String> list = new ArrayList<String>();
    regex = "<script.*?</script>";
    Pattern pa = Pattern.compile(regex, Pattern.DOTALL);
    Matcher ma = pa.matcher(s);
    while (ma.find()) ...{
      list.add(ma.group());
    }
    return list;
  }
  /** *//**
   *
   * @param s
   * @return   CSS
   */
  public List<String> getCSS(String s) ...{
    String regex;
    List<String> list = new ArrayList<String>();
    regex = "<style.*?</style>";
    Pattern pa = Pattern.compile(regex, Pattern.DOTALL);
    Matcher ma = pa.matcher(s);
    while (ma.find()) ...{
      list.add(ma.group());
    }
    return list;
  }
  /** *//**
   *
   * @param s
   * @return     
   */
  public String outTag(String s) ...{
    return s.replaceAll("<.*?>", "");
  }