java日期处置小例子

java日期处理小例子

import java.text.SimpleDateFormat;import java.util.Calendar;import java.util.Date;public class DaysPeriod {public static void main(String[] args) {Date now = new Date();Long fiveDaysAgo = now.getTime() - 1000 * 60 * 60 * 24 * 5;//5天前Calendar calendar = Calendar.getInstance();calendar.setTimeInMillis(fiveDaysAgo);calendar.set(Calendar.HOUR_OF_DAY, 0);calendar.set(Calendar.MINUTE, 0);calendar.set(Calendar.SECOND, 0);calendar.getTime();//5天前的 00:00:00SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-ddHH:mm:ss");         //看一下效果System.out.println(sdf.format(calendar.getTime()));//2011-07-17 00:00:00//days==0，表示得到的是今天==1,昨天...int days=(int((now.getTime()-calendar.getTimeInMillis())/(1000*60*60*24));System.out.println(days);//这里肯定等于5}}