public static boolean checkDate(String str) {
  boolean bolRet = true;
  if (StringUtils.isNotEmpty(str)) {
   try {
    SimpleDateFormat formatDate = new SimpleDateFormat("yyyy/MM/dd");
    //    將某個日期以固定格式轉化成字符串
   //    String str = sdf.format(formatDate );
    formatDate.setLenient(false);
    Calendar calendar = Calendar.getInstance();
    java.util.Date date = formatDate.parse(str);
    calendar.setTime(date);
    int nowYear = calendar.get(Calendar.YEAR);
    bolRet = (nowYear >= 2000) && (nowYear <= 9999)
      && formatDate.format(date).equals(str);
   } catch (Exception ex) {
    bolRet = false;
    System.out.println(ex);
   }
  }
  return bolRet;
 }