How to validate Hour and Minutes that came from a Swing textBox?

I have a window that contains a HH:mm time TextField in it, in 24 hours format

I need to validate if the user entered any non valid hour, like 28:00, 99:00, 24:01.

What's the best and simpler way to do that ?

some code below of what is currently doing that job wrong and giving errors in date parsed. Today I get an random hour and an user hit 99:99 in that text field.

This code is not mine, but I gotta fix it.

I am stuck with it, tried to validate as a String is useless, and I ca开发者_开发技巧nnot find a nice way to make it a Date without having to put year, month, etc... too.

Please forget about the return -1 instead of throwing an exception this is old code and this cannot be changed.

to help understand :

Statics.hF2 = SimpleDateFormat (HH:mm)

this.cmpHora.getText() = Is the field with the value

Statics.df_ddmmyy = Another date format

Statics.m2ms = converts minutes to milliseconds

//CODE

public long getDataEmLong ()
{
   try
   {
      Calendar hour= Calendar.getInstance();
      new GregorianCalendar().
      hour.setTime( Statics.hF2.parse( this.cmpHora.getText() ) );
      return Statics.df_ddmmyy.parse( this.cmpData.getText() ).getTime() + Statics.m2ms( hour.get( Calendar.HOUR_OF_DAY ) * 60 ) + Statics.m2ms( hour.get( Calendar.MINUTE ) );
   } catch ( Exception e )
   {
      e.printStackTrace();
      return -1;
   }

}

Cheers !

Regular expressions to the rescue:

public boolean validTime24(String time) {
    return time.matches("^([01]\d|2[0-3]):[0-5]\d$")
}

This will validate the format of the string. Then you can parse out the time from there.

Insert this in your class, and perform the validateTime method from inside your junk code.

public boolean validateTime(String timeString) {
    if (timeString.length() != 5) return false;
    if (!timeString.substring(2, 3).equals(":")) return false;
    int hour = validateNumber(timeString.substring(0, 2));
    int minute = validateNumber(timeString.substring(3));
    if (hour < 0 || hour >= 24) return false;
    if (minute < 0 || minute >= 60) return false;
    return true;
}

public int validateNumber(String numberString) {
    try {
        int number = Integer.valueOf(numberString);
        return number;
    } catch (NumberFormatException e) {
        return -1;
    }
}

You can use JFormattedTextField with proper Date or Time Format set. The field will return you proper values.

Since Java 8 you can use DateTimeFormatter:

public boolean validate(String time) {
        try {
            DateTimeFormatter timeFormatter = DateTimeFormatter.ofPattern("HH:mm");
            timeFormatter.parse(time);
            return true;
        } catch (DateTimeParseException e) {
            return false;
        }
    }