java_日历类

Posted 2022-03-12 aikang525

calendar是日历类，该类是抽象类不能被实例化

 1 public class CalendarTest 
 2     /*
 3     创建对象和方法的使用
 4      */
 5     public static void main(String[] args) 
 6         //实例化对象
 7         Calendar instance = Calendar.getInstance();
 8         //说明是子类实现class java.util.GregorianCalendar
 9         System.out.println(instance.getClass());
10         //get方法得到本月的日
11         int day = instance.get(Calendar.DAY_OF_MONTH);
12         System.out.println(day);
13         //set设置日为10
14         instance.set(Calendar.DAY_OF_MONTH,10);
15         int day1 = instance.get(Calendar.DAY_OF_MONTH);
16         System.out.println(day1);
17         //add添加3天
18         instance.add(Calendar.DAY_OF_MONTH,3);
19         int day2 = instance.get(Calendar.DAY_OF_MONTH);
20         System.out.println(day2);
21         //把日历类转换为date
22         Date time = instance.getTime();
23         System.out.println(time);
24         //把date转为日历
25         Date date = new Date();
26         instance.setTime(date);
27         int i = instance.get(Calendar.DAY_OF_MONTH);
28         System.out.println(i);
29     
30