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