java 计算瑞年的方法

任何语言都有可能计算某一年是否为瑞年的方法，也就是说一年有 366 天，每隔4 年就出现一次。最基本的算法如下：

if year is divisible by 400 then
   is_leap_year
else if year is divisible by 100 then
   not_leap_year
else if year is divisible by 4 then
   is_leap_year
else
   not_leap_year

知道了这个基本算法，那么起始与语言无关了，这里就用JAVA 语言做一个讲解

public class DateTimeExample {
 
    public static void main(String[] args) {
 
	DateTimeExample obj = new DateTimeExample();
	System.out.println("1993 is a leap year : " + obj.isLeapYear(1993));
	System.out.println("1996 is a leap year : " + obj.isLeapYear(1996));
	System.out.println("2012 is a leap year : " + obj.isLeapYear(2012));
 
    }
 
    public boolean isLeapYear(int year) {
 
	if ((year % 400 == 0) || ((year % 4 == 0) && (year % 100 != 0))) {
		return true;
	} else {
		return false;
	}
    }
 
}

输出结果如下

1993 is a leap year : false
1996 is a leap year : true
2012 is a leap year : true

当然，起始用Calendar 也是可以计算出来的.

 import java.util.GregorianCalendar;
 
    //...
    public boolean isLeapYear(int year) {
 
	GregorianCalendar cal = (
		GregorianCalendar) GregorianCalendar.getInstance();
 
	return cal.isLeapYear(year);
    }

From：一号门