JAVA: use regex to validate date and time.

I tried to search correct regex for date and time on google and found that many of them are not working.

Finally, I found the correct one and the java methods shows below.

 /**  
  * Check that a date is formatted according to the following convention:  
  * DD/MM/YYYY OR DD.MM.YYYY OR DD-MM-YYYY  
  * @param dateStr a date string.  
  * @return true if the date text should be rejected  
  */  
  private boolean invalidDate(String dateStr) {  
  String regex = "^(0[1-9]|[12][0-9]|3[01])[- /.](0[1-9]|1[012])[- /.](19|20)\\d\\d$";  
  return !Pattern.matches(regex, dateStr);  
  }  
  /**  
  * Check that a time is formatted according to the following convention:  
  * HH:MM:SS AM/PM  
  * @param timeStr a time string.  
  * @return true if the time text should be rejected  
  */  
  private boolean invalidTime(String timeStr) {  
  String regex = "^(([0]?[1-9])|([1][0-2])):(([0-5][0-9])|([1-9])):([0-5][0-9]) [AP][M]$";  
  return !Pattern.matches(regex, timeStr);  
  }