java时间运算收藏

import java.text.SimpleDateFormat;
import java.util.Calendar;
public class DateAll {
 public static void main(String[] args) throws Exception {
//当前时间
    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);
//两个时间之间的天数
    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);
//加半小时
    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);
//求是星期几
   mydate= myFormatter.parse("2007-11-9");
   SimpleDateFormat formatter4 = new SimpleDateFormat("E");
   String mydate3=formatter4.format(mydate);
   System.out.println(mydate3);
 }
}