java日期公共类

 package com.mall.common;

 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Calendar;
 import java.util.Date;
 import java.util.List;

 import org.apache.log4j.Logger;

 public class DateUtils {
     private static Logger log=Logger.getLogger(DateUtils.class);

     /**
      * 获取昨天日期
      *
      * @param date
      * @return
      */
     public static String getYesterDay(Date date) {

         java.text.Format formatter = new java.text.SimpleDateFormat(
                 "yyyy-MM-dd");

         long beforeTime = (date.getTime() / 1000) - 24 * 60 * 60;

         date.setTime(beforeTime * 1000);

         return formatter.format(date);

     }

     /**
      * 获取昨天日期(返回数值)
      *
      * @param date
      * @return num
      */
     public static Integer getYesterDayNum(Date date) {

         java.text.Format formatter = new java.text.SimpleDateFormat("yyyyMMdd");

         long beforeTime = (date.getTime() / 1000) - 24 * 60 * 60;

         date.setTime(beforeTime * 1000);

         return Integer.parseInt(formatter.format(date));

     }

     /**
      * 获取一周前的日期(当前日期往前推7天)
      *
      * @param date
      * @return
      */
     public static String getWeekdayBeforeDate(Date date) {

         java.text.Format formatter = new java.text.SimpleDateFormat(
                 "yyyy-MM-dd");

         long beforeTime = (date.getTime() / 1000) - 24 * 60 * 60 * 7;

         date.setTime(beforeTime * 1000);

         return formatter.format(date);

     }

     /**
      * 获取一周前的日期(当前日期往前推7天)(返回数值)
      *
      * @param date
      * @return
      */
     public static Integer getWeekdayBeforeDateNum(Date date) {

         java.text.Format formatter = new java.text.SimpleDateFormat("yyyyMMdd");

         long beforeTime = (date.getTime() / 1000) - 24 * 60 * 60 * 7;

         date.setTime(beforeTime * 1000);

         return Integer.parseInt(formatter.format(date));

     }

     /**
      * 获取一月前的日期(当前日期往前推30天)
      *
      * @param date
      * @return
      */
     public static String getMonthBeforeDate(Date date) {

         java.text.Format formatter = new java.text.SimpleDateFormat(
                 "yyyy-MM-dd");

         long beforeTime = (date.getTime() / 1000) - 24 * 60 * 60 * 30;

         date.setTime(beforeTime * 1000);

         return formatter.format(date);

     }

     /**
      * 获取一月前的日期(当前日期往前推30天)(返回数值)
      *
      * @param date
      * @return
      */
     public static Integer getMonthBeforeDateNum(Date date) {

         java.text.Format formatter = new java.text.SimpleDateFormat("yyyyMMdd");

         long beforeTime = (date.getTime() / 1000) - 24 * 60 * 60 * 30;

         date.setTime(beforeTime * 1000);

         return Integer.parseInt(formatter.format(date));

     }

     /**
      * 获取三月前的日期(当前日期往前推90天)
      *
      * @param date
      * @return
      */
     public static String get3MonthBeforeDate(Date date) {

         java.text.Format formatter = new java.text.SimpleDateFormat(
                 "yyyy-MM-dd");

         long beforeTime = (date.getTime() / 1000) - 24 * 60 * 60 * 30 * 3;

         date.setTime(beforeTime * 1000);

         String d = formatter.format(date);
         return d;
     }

     /**
      * 获取三月前的日期(当前日期往前推30天)(返回数值)
      *
      * @param date
      * @return
      */
     public static Integer get3MonthBeforeDateNum(Date date) {

         java.text.Format formatter = new java.text.SimpleDateFormat("yyyyMMdd");

         long beforeTime = (date.getTime() / 1000) - 24 * 60 * 60 * 30 * 3;

         date.setTime(beforeTime * 1000);

         return Integer.parseInt(formatter.format(date));

     }

     /**
      * 获取一年后的日期
      *
      * @return
      */
     public static String getNextYear(int chooseYear, Date date) {

         java.text.Format formatter = new java.text.SimpleDateFormat(
                 "yyyy-MM-dd");

         long beforeTime = (date.getTime() / 1000) + 60 * 60 * 24 * 365
                 * chooseYear;

         date.setTime(beforeTime * 1000);

         return formatter.format(date);
     }

     /**
      * 日期转换成字符串
      *
      * @param date
      * @return
      */
     public static String convertDateToStr(Date date) {
         java.text.Format formatter = new java.text.SimpleDateFormat(
                 "yyyy-MM-dd");
         return formatter.format(date);

     }

     /**
      * 日期转换成字符串 yyyy-MM-dd HHmmss
      *
      * @param date
      * @return
      */
     public static String convertTimeToStr(Date date) {
         java.text.Format formatter = new java.text.SimpleDateFormat(
                 "yyyy-MM-dd HH:mm:ss");
         return formatter.format(date);

     }

     /**
      * 将日期转为数值
      *
      * @param date
      * @return
      */
     public static Integer convertDateToNum(Date date) {
         java.text.Format formatter = new java.text.SimpleDateFormat("yyyyMMdd");
         return Integer.parseInt(formatter.format(date));
     }
     /**
      * 将字符串日期转为数值
      *
      * @param date
      * @return
      */
     public static Integer convertStrToNum(String date) {

         if (date.contains("-")) {
             date = date.replace("-", "");
         } else if (date.contains(".")) {
             date = date.replace(".", "");
         } else if (date.contains("/")) {
             date = date.replace("/", "");
         }

         return Integer.parseInt(date);
     }

     /**
      * 时间转换器 第一个参数 要转化的数据类型 --- java.util.Date 第二个参数 要转化的数据 --- "2010-12-12"
      *
      */
     public static Date convertStrTODate( String str,Class<Date> type,String datePattern) {

         if (str == null) {
             return null;
         } else {
             if (type == java.util.Date.class) {
                 if (str instanceof String) {
                     try {
                         SimpleDateFormat sdf = new SimpleDateFormat(datePattern);
                         return sdf.parse(str);
                     } catch (ParseException e) {
                         throw new RuntimeException("您输入的数据格式不对");
                     }
                 } else {
                     throw new RuntimeException("您要转化的数据输入不是String类型");
                 }
             } else {
                 throw new RuntimeException("您要转化的数据类型不对");
             }
         }
     }

     /**
      * 根据生日计算年龄
      *
      * @param birthDay
      * @return
      * @throws Exception
      */
     public static int getAge(Date birthDay) throws Exception {
         Calendar cal = Calendar.getInstance();

         if (cal.before(birthDay)) {
             throw new IllegalArgumentException(
                     "The birthDay is before Now.It's unbelievable!");
         }
         int yearNow = cal.get(Calendar.YEAR);
         int monthNow = cal.get(Calendar.MONTH);
         int dayOfMonthNow = cal.get(Calendar.DAY_OF_MONTH);
         cal.setTime(birthDay);

         int yearBirth = cal.get(Calendar.YEAR);
         int monthBirth = cal.get(Calendar.MONTH);
         int dayOfMonthBirth = cal.get(Calendar.DAY_OF_MONTH);

         int age = yearNow - yearBirth;

         if (monthNow <= monthBirth) {
             if (monthNow == monthBirth) {
                 // monthNow==monthBirth
                 if (dayOfMonthNow < dayOfMonthBirth) {
                     age--;
                 } else {
                     // do nothing
                 }
             } else {
                 // monthNow>monthBirth
                 age--;
             }
         } else {
             // monthNow<monthBirth
             // donothing
         }

         return age;
     }
     ///////////////////////////////////////根据时间段获取时间的集合//////////////////////////////////////////////////////////////////
     public static List<String> getDateListBydates(String s1,String s2,String format) throws ParseException{
         List<String>list=new ArrayList<String>();
         //String s1 = "2012-02-01";
         //String s2 = "2012-04-04";
         SimpleDateFormat sdf = new SimpleDateFormat(format);
         Date   begin=sdf.parse(s1);
         Date   end=sdf.parse(s2);
         double   between=(end.getTime()-begin.getTime())/1000;//除以1000是为了转换成秒
         double  day=between/(24*3600);
         for(int i = 0;i<=day;i++){
             Calendar cd = Calendar.getInstance();
             cd.setTime(sdf.parse(s1));
             cd.add(Calendar.DATE, i);//增加一天
             //cd.add(Calendar.MONTH, n);//增加一个月
             log.info(sdf.format(cd.getTime()));
             list.add(sdf.format(cd.getTime()));
         }
         return list;
     }
     //获取指定年月的总天数
     public static int getLastDay(int year, int month) {
         int day = 1;
         Calendar cal = Calendar.getInstance();
         cal.set(year,month - 1,day);
         int last = cal.getActualMaximum(Calendar.DATE);
         System.out.println(last);
         return last;
     }
     //获取指定年月的日期
     @SuppressWarnings("unchecked")
     public static List<String> getDatesByMonth(int year, int month){
         List<String> list=new ArrayList();
         String yyyy=year+"";
         String mm=month+"";
         String dd="01";
         if(month<10){
             mm="0"+month;
         }
         int num=getLastDay(year, month);
         for(int i=1;i<=num;i++){
             if(i<10){
                 dd="0"+i;
             }else{
                 dd=i+"";
             }
             list.add(yyyy+"-"+mm+"-"+dd);
             System.out.println(yyyy+"-"+mm+"-"+dd);
         }
         return list;
     }
     /**
      *
      * @param datestr 解析字符串  如2014-04-1716:38:57
      * @param sourceDateformat 源日期格式 如yyyy-MM-ddHH:mm:ss
      * @param formatStr 要转换的日期格式 如(yyyy-MM-dd HH:mm:ss)
      * @return
      */
     public static String strTOdateTOStr(String datestr,String sourceDateformat,String targetDateformat){
 //        String str="2014-04-1716:38:57";
         try {
             SimpleDateFormat sourceFormat = new SimpleDateFormat(sourceDateformat);
             SimpleDateFormat targetFormat = new SimpleDateFormat(targetDateformat);
             return targetFormat.format(sourceFormat.parse(datestr));
         } catch (Exception e) {
             log.info("strTOdateTOStr:"+e);
         }
         return null;

     }
     /////////////////////////////////////////////////////////////////////////////////////////////////////////

     public static void main(String[] args) throws Exception{
         //getDatesByMonth(2013,2);
         getDateListBydates("20130517","20130519","yyyyMMdd");

     }

 }