java 日期加减运算

第一个未测试，第二个可用

1.用java.util.Calender来实现

Calendar calendar=Calendar.getInstance();   
calendar.setTime(new Date());
System.out.println(calendar.get(Calendar.DAY_OF_MONTH));//今天的日期 
calendar.set(Calendar.DAY_OF_MONTH,calendar.get(Calendar.DAY_OF_MONTH)+1);//让日期加1   
System.out.println(calendar.get(Calendar.DATE));//加1之后的日期Top

2.用java.text.SimpleDateFormat和java.util.Date来实现

Date d=new Date();   
SimpleDateFormat df=new SimpleDateFormat("yyyy-MM-dd");   
System.out.println("今天的日期："+df.format(d));   
System.out.println("两天前的日期：" + df.format(new Date(d.getTime() - ((long)2 * 24 * 60 * 60 * 1000))));   
System.out.println("三天后的日期：" + df.format(new Date(d.getTime() + ((long)3 * 24 * 60 * 60 * 1000))));

摘自：http://www.blogjava.net/willpower88/archive/2006/12/07/86012.html