@Size annotation to validate a field

Question

I need to validate a field - secPhoneNumber (secondary phone #). I need to satisfy below conditions using JSR validation

The field can be empty/null
Otherwise, the data must be of length 10.

I tried the code below. The field is always getting validated on form submission. How do I validate the field to be of length 10 only when it is not empty?

Spring Form:

<form:label path="secPhoneNumber">
Secondary phone number <form:errors path="secPhoneNumber" cssClass="error" />
</form:label>
<form:input path="secPhoneNumber" />

Bean

@Size(max=10,min=10)
    private String secPhoneNumber;

Should me `@Length` for a String. And it is not checked when the value is null. — J.Mengelle, Jul 06 '16 at 13:06
Mengelle, Thanks for your input. Tried using @Length(max=10,min=10) private String secPhoneNumber , but doesn't fulfill the use case. — Andy, Jul 07 '16 at 01:50
Sorry, `@Size` was valid with javax.validation, but not hibernate validator. I don't know what you use. Anyway, if your need is : not required, but when provided the length = 10 (it is what i understood), this should be ok. Note that an empty string is considered as a value, so the `@Size` will be trigered. You need null value if not provided, then the validation will not be trigerred. For more details : http://stackoverflow.com/questions/11550324/sizemin-max-but-not-required — J.Mengelle, Jul 07 '16 at 12:30

score 2 · Answer 1 · answered Jul 07 '16 at 11:05

I think for readability and to use in future times i would create my custom validation class, you only should follow this steps:

Add your new custom annotation to your field

@notEmptyMinSize(size=10)
private String secPhoneNumber;

Create the custom validation classes

@Documented
@Constraint(validatedBy = notEmptyMinSize.class)
@Target( { ElementType.METHOD, ElementType.FIELD })
@Retention(RetentionPolicy.RUNTIME)
public @interface notEmptyMinSize {


    int size() default 10;

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

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

}

Add your business logic to your validation

public class NotEmptyConstraintValidator implements      ConstraintValidator<notEmptyMinSize, String> {

     private NotEmptyMinSize notEmptyMinSize;

     @Override
     public void initialize(notEmptyMinSize notEmptyMinSize) { 
         this.notEmptyMinSize = notEmptyMinSize
     }

     @Override
     public boolean isValid(String notEmptyField, ConstraintValidatorContext cxt) {
        if(notEmptyField == null) {
             return true;
        }
        return notEmptyField.length() == notEmptyMinSize.size();
    }

}

And now you could use this validation in several fields with different sizes.

Here another example you can follow example

score 1 · Answer 2 · edited Jul 28 '18 at 05:33

Following patterns work

@Pattern(regexp="^(\s*|[a-zA-Z0-9]{10})$")
@Pattern(regexp="^(\s*|\d{10})$")

// ^             # Start of the line
// \s*           # A whitespace character, Zero or more times
// \d{10}        # A digit: [0-9], exactly 10 times
//[a-zA-Z0-9]{10}    # a-z,A-Z,0-9, exactly 10 times
// $             # End of the line

Reference: Validate only if the field is not Null

@Size annotation to validate a field

2 Answers2

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