Question

I have a text box which accepts time in the format HH:mm and entries should only be in 24-hour format.For all invalid entries, a common message ‘Invalid entry’ should be displayed.

For eg:

19:61 //INVALID
12:00am //INVALID
12***M //INVALID

06:00 //VALID
22:00 //VALID
5:45 //VALID

The code required is in Java.
Not familiar with regex expressions…so need your ideas on it.Thx in advance! 🙂

String timeStr = getTimeBoxValue();

Answer 1

There is a Link
Which you can use.

import java.util.regex.Matcher;
import java.util.regex.Pattern;

public class Time24HoursValidator{

  private Pattern pattern;
  private Matcher matcher;

  private static final String TIME24HOURS_PATTERN = 
             "([01]?[0-9]|2[0-3]):[0-5][0-9]";

  public Time24HoursValidator(){
      pattern = Pattern.compile(TIME24HOURS_PATTERN);
  }

  /**
   * Validate time in 24 hours format with regular expression
   * @param time time address for validation
   * @return true valid time fromat, false invalid time format
   */
  public boolean validate(final String time){

      matcher = pattern.matcher(time);
      return matcher.matches();

  }
}