Java尽量精确地抽取网页的发布时间

对网页中各种不同格式的发布时间进行抽取，将发布时间以规整的“yyyy-MM-dd HH:mm:ss”格式表示出来，只能尽量追求精确，但是因为网络发布时间的格式十分灵活，所以做不到百分百地正确抽取

package whu.extract.pubtime.core;
 
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Collections;
import java.util.List;
import java.util.regex.Matcher;
import java.util.regex.Pattern;
 
import whu.utils.TimeUtil;
 
/**
 * Created On 2014年3月13日 下午2:49:05
 * @description 获取网页的发布时间 
 */
public class FetchPubTime {
    /** 表示url中连续的8位日期，例如http://www.baidu.com/20140311/2356.html */
    private static String url_reg_whole= "([-|/|_]{1}20\\d{6})";
    /** 表示 用-或者/隔开的日期,有年月日的，例如 http://www.baidu.com/2014-3-11/2356.html  */
    private static String url_reg_sep_ymd = "([-|/|_]{1}20\\d{2}[-|/|_]{1}\\d{1,2}[-|/|_]{1}\\d{1,2})";
    /** 表示 用-或者/隔开的日期,只有年和月份的，例如 http://www.baidu.com/2014-3/2356.html  */
    private static String url_reg_sep_ym = "([-|/|_]{1}20\\d{2}[-|/|_]{1}\\d{1,2})";
    private static Calendar current = Calendar.getInstance();
    /** 格式正确的时间正则表达式*/
    private static String rightTimeReg = "^((\\d{2}(([02468][048])|([13579][26]))[\\-\\/\\s]?((((0?[13578])|(1[02]))[\\-\\/\\s]?((0?[1-9])|([1-2][0-9])|(3[01])))|(((0?[469])|(11))[\\-\\/\\s]?((0?[1-9])|([1-2][0-9])|(30)))|(0?2[\\-\\/\\s]?((0?[1-9])|([1-2][0-9])))))|(\\d{2}(([02468][1235679])|([13579][01345789]))[\\-\\/\\s]?((((0?[13578])|(1[02]))[\\-\\/\\s]?((0?[1-9])|([1-2][0-9])|(3[01])))|(((0?[469])|(11))[\\-\\/\\s]?((0?[1-9])|([1-2][0-9])|(30)))|(0?2[\\-\\/\\s]?((0?[1-9])|(1[0-9])|(2[0-8]))))))(\\s(((0?[0-9])|([1-2][0-3]))\\:([0-5]?[0-9])((\\s)|(\\:([0-5]?[0-9])))))?$";
     
    /**
     * @param url
     * @param urlContent
     * @return
     */
    public static String getPubTimeVarious(String url,String urlContent) {
         
        String pubTime = getPubTimeFromUrl(url);
         
      //链接里面没有，匹配文本中的
        if(pubTime == null)
        {
            if(urlContent!=null&&!urlContent.trim().equals(""))
                return extractPageDate(urlContent);
        }
         
        return pubTime;
    }
     
    /**从url里面抽取出发布时间，返回YYYY-MM-DD HH:mm:ss格式的字符串
     * @param url
     * @return
     */
    public static String getPubTimeFromUrl(String url)
    {
        Pattern p_whole = Pattern.compile(url_reg_whole);
        Matcher m_whole = p_whole.matcher(url);
        if(m_whole.find(0)&&m_whole.groupCount()>0)
        {
           String time =  m_whole.group(0);
           time = time.substring(1,time.length());
           //每一步都不能够超出当前时间          
        if(current.compareTo(TimeUtil.strToCalendar(time, "yyyyMMdd"))>=0)
        {
 
           return time.substring(0,4)+"-"+time.substring(4,6)+"-"+
                  time.substring(6,8)+" "+"00:00:00";
        }
        }
       
        p_whole = null;
        m_whole = null;
        Pattern p_sep = Pattern.compile(url_reg_sep_ymd);
        Matcher m_sep = p_sep.matcher(url);
        if(m_sep.find(0)&&m_sep.groupCount()>0)
        {
             String time =  m_sep.group(0);
             time = time.substring(1,time.length());
             String[] seg = time.split("[-|/|_]{1}");
             Calendar theTime = Calendar.getInstance();
             theTime.set(Calendar.YEAR,Integer.parseInt(seg[0]));
             theTime.set(Calendar.MONTH, Integer.parseInt(seg[1]));
             theTime.set(Calendar.DAY_OF_MONTH, Integer.parseInt(seg[2]));
             if(current.compareTo(theTime)>=0)
                {
             
            return seg[0]+"-"+seg[1]+"-"+seg[2]+" "+"00:00:00";
                }
        }
        p_sep = null;
        m_sep = null;
        Pattern p_sep_ym = Pattern.compile(url_reg_sep_ym);
        Matcher m_sep_ym = p_sep_ym.matcher(url);
        if(m_sep_ym.find(0)&&m_sep_ym.groupCount()>0)
        {
             String time =  m_sep_ym.group(0);
             time = time.substring(1,time.length());
             Calendar theTime = Calendar.getInstance();
             String[] seg = time.split("[-|/|_]{1}");
             theTime.set(Calendar.YEAR,Integer.parseInt(seg[0]));
             theTime.set(Calendar.MONTH, Integer.parseInt(seg[1]));
             theTime.set(Calendar.DAY_OF_MONTH, 1);
             if(current.compareTo(theTime)>=0)
            {
              
            return seg[0]+"-"+seg[1]+"-"+"01"+" "+"00:00:00";
            }
        }
         
        return null;
    }
     
 
    /** 从网页源码中取出发布时间
     *  java中正则表达式提取字符串中日期实现代码
     *  2013年12月19日15:58:42
     *  读取出2013-12-19 15:48:33或者2013-12-19或者2012/3/05形式的时间
     * @param text 待提取的字符串
     * @return 返回日期
     * @author: oschina
     * @Createtime: Jan 21, 2013
     */
    public static String extractPageDate(String text) { 
        boolean  containsHMS =false;
        String dateStr = text.replaceAll("r?n", " ");
        try { 
            List matches = null; 
            Pattern p_detail = Pattern.compile("(20\\d{2}[-/]\\d{1,2}[-/]\\d{1,2} \\d{1,2}:\\d{1,2}:\\d{1,2})|(20\\d{2}年\\d{1,2}月\\d{1,2}日)", Pattern.CASE_INSENSITIVE|Pattern.MULTILINE); 
            //如果是仅仅抽取年月日，则按照上面的，如果是抽取年月日-时分秒，则按照下面的
            Pattern p = Pattern.compile("(20\\d{2}[-/]\\d{1,2}[-/]\\d{1,2})|(20\\d{2}年\\d{1,2}月\\d{1,2}日)", Pattern.CASE_INSENSITIVE|Pattern.MULTILINE);
            //Matcher matcher = p.matcher(dateStr);
            Matcher matcher_detail = p_detail.matcher(dateStr);
             
            if(!(matcher_detail.find(0) && matcher_detail.groupCount() >= 1)) 
            {
                matcher_detail = p.matcher(dateStr);
                containsHMS  = true;
            }else
                matcher_detail = p_detail.matcher(dateStr);
            if (matcher_detail.find() && matcher_detail.groupCount() >= 1) { 
                matches = new ArrayList(); 
                for (int i = 1; i <= matcher_detail.groupCount(); i++) { 
                    String temp = matcher_detail.group(i); 
                    matches.add(temp); 
                } 
            } else { 
                matches = Collections.EMPTY_LIST; 
            }            
 
            if (matches.size() > 0) { 
                for(int i=0;i<matches.size();i++)
                {
                    String pubTime = matches.get(i).toString().trim();
                    //取出第一个值
                    pubTime = pubTime.replace("/", "-").replace("年", "-").replace("月", "-").replace("日", "-");
                    if(current.compareTo(TimeUtil.strToCalendar(pubTime, "yyyy-MM-dd"))>=0)
                    {
                        if(containsHMS)
                            pubTime+=" "+"00:00:00";
                        if(pubTime.matches(rightTimeReg))
                        {
                            return pubTime; 
                        }
                    }
                }
            } else { 
                return null; 
            } 
             
        } catch (Exception e) { 
            return null; 
        } 
        return null;
    }
}