高级爬虫实战-系统掌握破解反爬技能

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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;
}