Calendar類的概述和獲取日期的方法
- A:Calendar類的概述
- Calendar 類是一個抽象類,它爲特定瞬間與一組諸如 YEAR、MONTH、DAY_OF_MONTH、HOUR 等日曆字段之間的轉換提供了一些方法,併爲操作日曆字段(例如獲得下星期的日期)提供了一些方法。
- B:成員方法
- public static Calendar getInstance()
- public int get(int field)
- public void add(int field,int amount)
- public final void set(int year,int month,int date)
- C:案例演示
package com.heima.otherclass;
import java.util.Calendar;
public class Demo08_Calendar {
public static void main(String[] args) {
demo01();
Calendar c = Calendar.getInstance(); //父類引用指向子類對象
//c.add(Calendar.MONTH, -1); //對指定的字段進行向前減或向後加
//c.set(Calendar.YEAR, 2000); //修改指定字段
c.set(2000, 7, 8);
System.out.println(c.get(Calendar.YEAR) + "年" + getNum((c.get(Calendar.MONTH)+1))
+ "月" + getNum(c.get(Calendar.DAY_OF_MONTH)) + "日" + getWeek(c.get(Calendar.DAY_OF_WEEK)));
}
public static void demo01() {
Calendar c = Calendar.getInstance(); //父類引用指向子類對象
//System.out.println(c);
System.out.println(c.get(Calendar.YEAR)); //通過字段獲取年
System.out.println(c.get(Calendar.MONTH)); //通過字段後期月,但是月是從0開始編號的
System.out.println(c.get(Calendar.DAY_OF_MONTH));//月中的第幾天
System.out.println(c.get(Calendar.DAY_OF_WEEK) +"---------");//週日是第一天,週六是最後一天
System.out.println(c.get(Calendar.YEAR) + "年" + getNum((c.get(Calendar.MONTH)+1))
+ "月" + getNum(c.get(Calendar.DAY_OF_MONTH)) + "日" + getWeek(c.get(Calendar.DAY_OF_WEEK)));
}
/*
* 將星期存儲表中進行查表
* 1,返回值類型String
* 2,參數列表int week
*/
public static String getWeek(int week) {
String[] arr = {"","星期日","星期一","星期二","星期三","星期四","星期五","星期六"};
return arr[week];
}
/*
* 如果是個數數字前面補0
* 1,返回值類型String類型
* 2,參數列表,int num
*/
public static String getNum(int num) {
/*if(num > 9) {
return "" + num;
}else {
return "0" + num;
}*/
return num > 9 ? "" + num : "0" + num;
}
}