Java String Date Validation Using Hibernate API

Question

I am attempting to validate String Date using javax.validation & Hibernate validation. i need to check given String date should be past and it should be correct yyyyMMdd format with all constraints like leap year, 30th, 31st day.

 public class UserInformation {

        @NotNull 
        public String idNum = null;

        @NotNull
        //@Past
        @Pattern(regexp="\\d{4}(1[012]|0[1-9])(3[01]|[12]\\d|0[0-9])")
        public String dob= null;

    }

I tried with this code but not working. Is there any solution. if we have custom validator then is it in field level.Please give suggestion or code snippet.

Robi

why don't you save as a date/timestamp/etc ? – Dolichocephalic

My requirement is to accept as String.. – Robi

Answer 1

Option 1

Change your pattern to this:

Pattern(regexp = "([0-2][0-9]|3[0-1])\/(0[1-9]|1[0-2])\/[0-9]{4}")

But keep in mind that this kind of validation is not checking if February has less than 28/29 days, and other dates constraints.

Options 2

Create your custom constraint validator

Annotation

@Target({ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER, ElementType.ANNOTATION_TYPE })
@Retention(RUNTIME)
@Constraint(validatedBy = CheckDateValidator.class)
@Documented
public @interface CheckDateFormat {

    String message() default "{message.key}";

    Class<?>[] groups() default { };

    Class<? extends Payload>[] payload() default { };

    String pattern();

}

Validator class

Having the Date object you can do any other validation you want (like refuse dates in the past)

public class CheckDateValidator implements ConstraintValidator<CheckDateFormat, String> {

    private String pattern;

    @Override
    public void initialize(CheckDateFormat constraintAnnotation) {
        this.pattern = constraintAnnotation.pattern();
    }

    @Override
    public boolean isValid(String object, ConstraintValidatorContext constraintContext) {
        if ( object == null ) {
            return true;
        }

        try {
            Date date = new SimpleDateFormat(pattern).parse(object);
            return true;
        } catch (Exception e) {
            e.printStackTrace();
            return false;
        }
    }
}

Use

@CheckDateFormat(pattern = "ddMMyyyy")
private String value;

Dolichocephalic

Sorry to Ask this question. where to put @CheckDateFormat(pattern = "ddMMyyyy").. i cannot put like this. @CheckDateFormat(pattern = "ddMMyyyy") public String dob= null; & What should be the values for FIELD, METHOD, PARAMETER, ANNOTATION_TYPE. – Robi

FIELD, METHOD, etc are static values of ElementType, I made some edits – Dolichocephalic

This one is not validating Feb 29 1987.. it returns true.. So i changed code as.. DateFormat dateFormat = new SimpleDateFormat( pattern ); dateFormat.setLenient( false ); try { dateFormat.parse(object); return true; } catch (ParseException e) { return false; } Now its working.. – Robi

Its really helped me. Thank you so much dude. – Robi

I'm noob with regex, would you be able to explain what does [0-2][0-9]/[0-1][0-9]/[0-9]{4} mean? – Asthenosphere

@Asthenosphere that regex is not correct, you'll probably want something like this: ([0-2][0-9]|3[0-1])\/[0-1][0-9]\/[0-9]{4}. I advice you to do some research on regex, regex101.com is a very useful site – Dolichocephalic

This parse it wrongly when I add pattern = "yyyy-MM-dd-HH:mm" and value as "2022-23-23-04:00" it still sends true. – Kopeisk

Thank you for the feedback @Kedar9444. Interesting behaviour, you should set simpleDateFormat.setLenient(false) before parsing to deal with that. But at this point in time if you can use java 8 time api, you should give it a try: LocalDateTime.parse("2022-12-23-04:00", DateTimeFormat.forPattern("yyyy-MM-dd-HH:mm")) – Dolichocephalic