java获取一年的周数和间隔天数

java获取一年的周数和间隔天数

 import java.text.ParseException;
 import java.text.SimpleDateFormat;
 import java.util.*;

 public class Test {

     private static Date deformatDatetime(String strDate, String fmt) {
         try {
             if (fmt == null) {
                 return (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss",
                         java.util.Locale.ENGLISH)).parse(strDate);
             } else {
                 return (new SimpleDateFormat(fmt, java.util.Locale.ENGLISH))
                         .parse(strDate);
             }
         } catch (ParseException e) {
             // TODO Auto-generated catch block
             e.printStackTrace();
             return null;
         }
     }
     private static String datetimeToString(Date dt, String fmt) {
         if (fmt == null) {
             return (new SimpleDateFormat("yyyy-MM-dd HH:mm:ss",
                     java.util.Locale.ENGLISH)).format(dt);
         } else {
             return (new SimpleDateFormat(fmt, java.util.Locale.ENGLISH))
                     .format(dt);
         }
     }
     private static class DateRange{
         public Date startDate;
         public Date endDate;
         public DateRange(){

         }
         public DateRange(Date dt1,Date dt2){
             startDate=dt1;
             endDate=dt2;
         }
     }
     /**
      * 根據年份獲得該年所有周次及每周的開始-結束日期
      * @param pvnYear
      * @return
      */
     private static LinkedHashMap<Integer,DateRange> getWeeksDetByYear(int pvnYear){
         LinkedHashMap<Integer, DateRange> lvRet=new LinkedHashMap<Integer,DateRange>();
         Calendar lvCal=Calendar.getInstance();
         lvCal.setFirstDayOfWeek(Calendar.MONDAY);

         Date lvDt=deformatDatetime(String.valueOf(pvnYear)+"-01-01 00:00:00", null);
         lvCal.setTime(lvDt);
         int lvWeek=1;
         while (true) {
             lvCal.set(Calendar.DAY_OF_WEEK, lvCal.getFirstDayOfWeek()); // Monday
             Date lvFirstDt=lvCal.getTime();
             if (lvFirstDt.getYear()+1900<pvnYear){
                 lvFirstDt=lvDt;
             }
             if (lvFirstDt.getYear()+1900>pvnYear) break;
             lvCal.set(Calendar.DAY_OF_WEEK, lvCal.getFirstDayOfWeek()+6); // Sunday?
             Date lvLastDt=lvCal.getTime();
             if (lvLastDt.getYear()+1900>pvnYear){
                 lvLastDt=deformatDatetime(String.valueOf(pvnYear+1)+"-01-01 00:00:00", null);
                 lvCal.setTime(lvLastDt);
                 lvCal.add(Calendar.DAY_OF_YEAR, -1);
                 lvLastDt=lvCal.getTime();
             }
             lvRet.put(Integer.valueOf(lvWeek), new DateRange(lvFirstDt, lvLastDt));
             lvWeek++;
             lvCal.add(Calendar.WEEK_OF_YEAR, 1);
         }
         return lvRet;
     }
     public static void main(String[] args) throws  Exception{
         SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd");
         LinkedHashMap<Integer,DateRange>  lvRet=getWeeksDetByYear(2011);
         for (Map.Entry<Integer, DateRange> item:lvRet.entrySet()){
             String startDate = datetimeToString(item.getValue().startDate,"yyyy-MM-dd");
             String endDate = datetimeToString(item.getValue().endDate,"yyyy-MM-dd");
             Date date1 = format.parse(startDate);
             Date date2 = format.parse(endDate);
             int diff = differentDays(date1,date2);
             System.out.println(String.format("Week: %d, %s - %s", item.getKey(),datetimeToString(item.getValue().startDate,"yyyy-MM-dd"),
                     datetimeToString(item.getValue().endDate,"yyyy-MM-dd"))+" ----------"+diff);
         }
     }

     public static int differentDays(Date date1,Date date2)
     {
         Calendar cal1 = Calendar.getInstance();
         cal1.setTime(date1);

         Calendar cal2 = Calendar.getInstance();
         cal2.setTime(date2);
         int day1= cal1.get(Calendar.DAY_OF_YEAR);
         int day2 = cal2.get(Calendar.DAY_OF_YEAR);

         int year1 = cal1.get(Calendar.YEAR);
         int year2 = cal2.get(Calendar.YEAR);
         if(year1 != year2)   //同一年
         {
             int timeDistance = 0 ;
             for(int i = year1 ; i < year2 ; i ++)
             {
                 if(i%4==0 && i%100!=0 || i%400==0)    //闰年
                 {
                     timeDistance += 366;
                 }
                 else    //不是闰年
                 {
                     timeDistance += 365;
                 }
             }

             return timeDistance + (day2-day1) ;
         }
         else    //不同年
         {
             return day2-day1;
         }
     }
 }