java時間運算收藏

import java.text.SimpleDateFormat;
import java.util.Calendar;
public class DateAll {
public static void main(String[] args) throws Exception {
//當前時間
Calendar cal = Calendar.getInstance();
//SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss G E D F w W a E F");
String mDateTime=formatter.format(cal.getTime());
System.out.println(mDateTime);
//1年前日期
java.util.Date myDate=new java.util.Date();
long myTime=(myDate.getTime()/1000)-60*60*24*365;
myDate.setTime(myTime*1000);
String mDate=formatter.format(myDate);
System.out.println(mDate);
//明天日期
myDate=new java.util.Date();
myTime=(myDate.getTime()/1000)+60*60*24;
myDate.setTime(myTime*1000);
mDate=formatter.format(myDate);
System.out.println(mDate);
//兩個時間之間的天數
SimpleDateFormat myFormatter = new SimpleDateFormat("yyyy-MM-dd");
java.util.Date date= myFormatter.parse("1883-10-10");
java.util.Date mydate= myFormatter.parse("1899-12-30");
long day=(date.getTime()-mydate.getTime())/(24*60*60*1000);
System.out.println(day);
//加半小時
SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
java.util.Date date1 = format.parse("2002-02-28 23:16:00");
long Time=(date1.getTime()/1000)+60*30;
date1.setTime(Time*1000);
String mydate1=formatter.format(date1);
System.out.println(mydate1);
//年月周求日期
SimpleDateFormat formatter2 = new SimpleDateFormat("yyyy-MM F E");
java.util.Date date2= formatter2.parse("2003-05 5 星期五");
SimpleDateFormat formatter3 = new SimpleDateFormat("yyyy-MM-dd");
String mydate2=formatter3.format(date2);
System.out.println(mydate2);
//求是星期幾
mydate= myFormatter.parse("2007-11-9");
SimpleDateFormat formatter4 = new SimpleDateFormat("E");
String mydate3=formatter4.format(mydate);
System.out.println(mydate3);
}
}