In Spring MVC validation, Is it possible to show only one error message per field at a time?

Question

Example,

I have

@NotEmpty //tells you \'may not be empty\' if the field is empty
@Length(min = 2, max = 35) //tells you \'length must be between 2 an         


        

Answer 1

Yes it is possible. Just create your own annotation like this:

@Documented
@Constraint(validatedBy = {})
@Target({ ElementType.METHOD, ElementType.FIELD, ElementType.ANNOTATION_TYPE })
@Retention(RetentionPolicy.RUNTIME)
@ReportAsSingleViolation
@NotEmpty
@Length(min = 2, max = 35)
public @interface MyAnnotation {

    public abstract String message() default "{mypropertykey}";

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

    public abstract Class<?>[] payload() default {};
}

important part is the @ReportAsSingleViolation annotation

Answer 2

Use custom constraints for your field. For example, will use annotate @StringField.

@Target(ElementType.FIELD)
@Constraint(validatedBy = StringFieldValidator.class)
@Retention(RetentionPolicy.RUNTIME)

public @interface StringField {

    String message() default "Wrong data of string field";

    String messageNotEmpty() default "Field can't be empty";

    String messageLength() default "Wrong length of field";

    boolean notEmpty() default false;

    int min() default 0;

    int max() default Integer.MAX_VALUE;

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

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

Then make some logic in StringFieldValidator class. This class implemented by an interface ConstraintValidator <A extends Annotation, T>.

public class StringFieldValidator implements ConstraintValidator<StringField, String> {

    private Boolean notEmpty;
    private Integer min;
    private Integer max;
    private String messageNotEmpty;
    private String messageLength;

    @Override
    public void initialize(StringField field) {
        notEmpty = field.notEmpty();
        min = field.min();
        max = field.max();
        messageNotBlank = field.messageNotEmpty();
        messageLength = field.messageLength();
    }

    @Override
    public boolean isValid(String value, ConstraintValidatorContext context) {
        context.disableDefaultConstraintViolation();
        if (notEmpty && value.isEmpty()) {
            context.buildConstraintViolationWithTemplate(messageNotEmpty).addConstraintViolation();
            return false;
        }
        if ((min > 0 || max < Integer.MAX_VALUE) && (value.length() < min || value.length() > max)) {
            context.buildConstraintViolationWithTemplate(messageLength).addConstraintViolation();
            return false;
        }
        return true;
    }
}

Then you can use annotation like:

@StringField(notEmpty = true, min = 6, max = 64,
            messageNotEmpty = "Field can't be empty",
            messageLength = "Field should be 6 to 64 characters size")

And after all, you will have only one error message shown in right order.

Answer 3

A better solution would be to have some markup in your error message so that it formats nicely, such as a <br />, and use a CSS class to format the overall message. As noted in Bozho's comment, a user should be aware of everything that is incorrect.