Calendar常用方法

import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;

public class CalendarTest {
    public static void main(String[] args) {
        Calendar cal1=new GregorianCalendar(2019, 7, 23, 22, 11, 45);

        //System.out.println(cal1.get(Calendar.YEAR));
        //System.out.println(cal1.get(Calendar.DATE));

        //cal.set(Calendar.YEAR, 2020);
        //cal.set(2020, 5, 3, 12, 34, 89);

        //cal.add(Calendar.MONTH, -8);

        Date dd=cal1.getTime();//把日期转化成时间
        System.out.println(dd);

        Calendar cal2=new GregorianCalendar();  //把时间转化成日期
        cal2.setTime(dd);  //Calendar没有构造函数可以接收Date对象，必须先创建Calendar对象，然后调用setTime()方法
        System.out.println(cal2);
    }
}