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.

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;