Javaのカレンダクラス出力指定年の毎月最大日数

public class Demo01 {
	/**
	 *              
	 *  author:wangpeng
	 *  time：2018 8 9   4:04:33
	 */
	@Test
	public void test1() {
		Scanner in = new Scanner(System.in);
		System.out.println("    ：");
		String str = in.next();
		int year = 0;
		if (str.matches("\\d+")) {
			year = Integer.parseInt(str);
		} else {
			System.out.println("    ");
			return;
		}

		//      
		Calendar c = Calendar.getInstance();
		// Calendar c=new GregorianCalendar();
		if (year > 0)
			c.set(Calendar.YEAR, year);
		System.out.println("       ：" + year);
		for (int i = 0; i < 12; i++) {
			c.set(Calendar.MONTH, i);
			//            
			int actualMaximum = c.getActualMaximum(Calendar.DAY_OF_MONTH);
			System.out.println(i + 1 + "     ：" + actualMaximum);
		}
	}
}