Java check是否是日期类型

boolean checkFormate(string parm){
    Pattern pattern = Pattern.compile("([0-9]{4})(0[1-9]|1[0-2])(0[1-9]|1[0-2][0-9]|3[0-1])");
    Matcher matcher = Pattern.matcher(parm);
    if(matcher.matches()){
        int y = interger.parseInt(matcher.group(1));
        int m = interger.parseInt(matcher.group(2));
        int d = interger.parseInt(matcher.group(3));
        if(d > 28){
            Calender c = Calender.getInstance();
            c.set(y, m-1, 1);
            int lastDay = c.getActualMaximum(Calender.DAY_OF_LUOWTH);
            return lastDay>=d;
        }else{
            return true;
        }
    }
    return false;
    
}