计算某个月有几天？

import java.io.*;/** * 计算某个月有几天？ * @author Administrator * */class TestHaveDay {    public static void main(String []args)throws IOException {        System.out.println(days(2012,11));    }    public static int days(int year,int month) {        int days = 0;        if(month != 2) {            switch(month) {                case 1:                case 3:                case 5:                case 7:                case 8:                case 10:                case 12:days = 31 ;break;                case 4:                case 6:                case 9:                case 11:days = 30;             }        }else {            if(year%4==0 && year%100!=0 || year%400==0)                days = 29;            else  days = 28;        }        return days;    }}