Java检查日期(YYYYMMDD)和时间(hhmmss)的格式

/**
 * 检查日期 YYYYMMDD
 */
public static boolean checkDate(String str){
	boolean flag = false;
	try {
		String check = "(([0-9]{3}[1-9]|[0-9]{2}[1-9][0-9]{1}|[0-9]{1}[1-9][0-9]{2}|[1-9][0-9]{3})(((0[13578]|1[02])(0[1-9]|[12][0-9]|3[01]))|((0[469]|11)(0[1-9]|[12][0-9]|30))|(02(0[1-9]|[1][0-9]|2[0-8]))))|((([0-9]{2})(0[48]|[2468][048]|[13579][26])|((0[48]|[2468][048]|[3579][26])00))0229)(([0-1][0-9])|2[0-3])[0-5][0-9]";
		Pattern regex = Pattern.compile(check);
		Matcher matcher = regex.matcher(str);
		flag = matcher.matches();
	} catch (Exception e) {
		e.printStackTrace();
		flag = false;
	}
	return flag;
}
	
/**
 * 检查时间 hhmmss
 */
public static boolean checkTime(String str){
	boolean flag = false;
	try {
		String check = "(([01]\\d)|(2[0-3]))[0-5]\\d([0-5]\\d)?";
		Pattern regex = Pattern.compile(check);
		Matcher matcher = regex.matcher(str);
		flag = matcher.matches();
	} catch (Exception e) {
		e.printStackTrace();
		flag = false;
	}
	return flag;
}