java日期计算

功能：今天，昨天，本周，上周，本月，上月

范围：以周一作为一周的第一天，每周天数5天

代码：

import  java.util.Date;
 import  java.util.GregorianCalendar;


 public   class  TestCalendar  ... {

      public   static  String begin = "" ;
      public   static  String end = "" ;
      public   static  String now = new  java.sql.Date( new  Date().getTime()).toString();
      public   static   void  main(String[] args)  ... {
     
          // 今天 
         calcToday(begin,end,now, new  GregorianCalendar());
          // 昨天 
         calcYesterday(begin,end,now, new  GregorianCalendar());
          // 本周 
         calcThisWeek(begin,end,now, new  GregorianCalendar());
          // 上周 
         calcLastWeek(begin,end,now, new  GregorianCalendar());
          // 本月 
         calcThisMonth(begin,end,now, new  GregorianCalendar());
          // 上月 
         calcLastMonth(begin,end,now, new  GregorianCalendar());
         
     } 
      public   static   void  calcToday(String begin,String end,String now,GregorianCalendar calendar) ... {
         
         begin = now;
         end = now;
         System.out.println( " begin: " + begin);
         System.out.println( " end: " + end);
         System.out.println( " ---------------------- " );    
     } 
     
      public   static   void  calcYesterday(String begin,String end,String now,GregorianCalendar calendar) ... {

     
         calendar.add(GregorianCalendar.DATE,  - 1 );
         begin = new  java.sql.Date(calendar.getTime().getTime()).toString();
         end = begin;
         System.out.println( " begin: " + begin);
         System.out.println( " end: " + end);
         System.out.println( " ---------------------- " );    
     } 
     
      public   static   void  calcThisWeek(String begin,String end,String now,GregorianCalendar calendar) ... {
         end = now;
          int  minus = calendar.get(GregorianCalendar.DAY_OF_WEEK) - 2 ;
          if (minus < 0 ) ... {
             System.out.println( " 本周还没有开始，请查询上周 " );
             System.out.println( " ---------------------- " );
         } else ... {
     
         calendar.add(GregorianCalendar.DATE,  - minus);
         begin = new  java.sql.Date(calendar.getTime().getTime()).toString();
         System.out.println( " begin: " + begin);
         System.out.println( " end: " + end);
         System.out.println( " ---------------------- " );
         } 
     } 
     
      public   static   void  calcLastWeek(String begin,String end,String now,GregorianCalendar calendar) ... {
          int  minus = calendar.get(GregorianCalendar.DAY_OF_WEEK) + 1 ;
         calendar.add(GregorianCalendar.DATE, - minus);
         end = new  java.sql.Date(calendar.getTime().getTime()).toString();
         calendar.add(GregorianCalendar.DATE, - 4 );
         begin = new  java.sql.Date(calendar.getTime().getTime()).toString();
         System.out.println( " begin: " + begin);
         System.out.println( " end: " + end);
         System.out.println( " ---------------------- " );
     } 

      public   static   void  calcThisMonth(String begin,String end,String now,GregorianCalendar calendar) ... {
         end = now;
          int  dayOfMonth = calendar.get(GregorianCalendar.DATE);
         calendar.add(GregorianCalendar.DATE,  - dayOfMonth + 1 );
         begin = new  java.sql.Date(calendar.getTime().getTime()).toString();
         System.out.println( " begin: " + begin);
         System.out.println( " end: " + end);
         System.out.println( " ---------------------- " );
     } 
      public   static   void  calcLastMonth(String begin,String end,String now,GregorianCalendar calendar) ... {
         
         calendar.set(calendar.get(GregorianCalendar.YEAR),calendar.get(GregorianCalendar.MONTH), 1 );
         calendar.add(GregorianCalendar.DATE,  - 1 );
         end = new  java.sql.Date(calendar.getTime().getTime()).toString();
         
          int  month = calendar.get(GregorianCalendar.MONTH) + 1 ;
         begin = calendar.get(GregorianCalendar.YEAR) + " - " + month + " -01 " ;
                 
         System.out.println( " begin: " + begin);
         System.out.println( " end: " + end);
         System.out.println( " ---------------------- " );
     } 
 } 
 
 结果：

查询今天
begin:2007-12-18
end:2007-12-18
----------------------
查询昨天
begin:2007-12-17
end:2007-12-17
----------------------
查询本周
begin:2007-12-17
end:2007-12-18
----------------------
查询上周
begin:2007-12-10
end:2007-12-14
----------------------
查询本月
begin:2007-12-01
end:2007-12-18
----------------------
查询上月
begin:2007-11-01
end:2007-11-30