Question:
Develop a Java method to validate if a user-inputted string matches a specified date format, considering both date-only and datetime formats.
Solution:
After evaluating various approaches, we settled on using the SimpleDateFormat class. Here's the detailed implementation:
<code class="java">import java.text.ParseException; import java.text.SimpleDateFormat; import java.util.Date; public class DateFormatter { public static boolean isValidFormat(String format, String value) { Date date = null; SimpleDateFormat sdf = new SimpleDateFormat(format); try { date = sdf.parse(value); if (!value.equals(sdf.format(date))) { date = null; } } catch (ParseException e) { // Date parsing failed } return date != null; } public static void main(String[] args) { System.out.println("isValid - dd/MM/yyyy with 20130925 = " + isValidFormat("dd/MM/yyyy", "20130925")); System.out.println("isValid - dd/MM/yyyy with 25/09/2013 = " + isValidFormat("dd/MM/yyyy", "25/09/2013")); System.out.println("isValid - dd/MM/yyyy with 25/09/2013 12:13:50 = " + isValidFormat("dd/MM/yyyy", "25/09/2013 12:13:50")); System.out.println("isValid - yyyy-MM-dd with 2017-18--15 = " + isValidFormat("yyyy-MM-dd", "2017-18--15")); } }</code>
Usage:
Pass the required date format as the first argument and the input string as the second argument to the isValidFormat method. The method returns a boolean value indicating whether the input string matches the specified format.
Sample Output:
isValid - dd/MM/yyyy with 20130925 = false isValid - dd/MM/yyyy with 25/09/2013 = true isValid - dd/MM/yyyy with 25/09/2013 12:13:50 = false isValid - yyyy-MM-dd with 2017-18--15 = false
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