日历 - Calendar类
package com.atguigu.java;import org.junit.Test;import java.text.ParseException;import java.util.Calendar;/** * jdk 8之前的日期时间的API测试 * 1. System类中currentTimeMillis(); * 2. java.util.Date和子类java.sql.Date * 3. SimpleDateFormat * 4. Calendar * * @author shkstart * @create 2019 上午 11:35 */public class DateTimeTest { /* Calendar日历类(抽象类）的使用 */ @Test public void testCalendar(){ //1.实例化 //方式一：创建其子类（GregorianCalendar）的对象 //方式二：调用其静态方法getInstance() Calendar calendar = Calendar.getInstance();// System.out.println(calendar.getClass()); //2.常用方法 //get() int days = calendar.get(Calendar.DAY_OF_MONTH); System.out.println(days); System.out.println(calendar.get(Calendar.DAY_OF_YEAR)); //set() //calendar可变性 calendar.set(Calendar.DAY_OF_MONTH,22); days = calendar.get(Calendar.DAY_OF_MONTH); System.out.println(days); //add() calendar.add(Calendar.DAY_OF_MONTH,-3); days = calendar.get(Calendar.DAY_OF_MONTH); System.out.println(days); //getTime():日历类---> Date Date date = calendar.getTime(); System.out.println(date); //setTime():Date ---> 日历类 Date date1 = new Date(); calendar.setTime(date1); days = calendar.get(Calendar.DAY_OF_MONTH); System.out.println(days); }}
