Java日期计算

来自：http://esffor.iteye.com/blog/168233

 

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
----------------------