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Bean Validation API to dynamically instruct the validator to ignore specific constraint annotations on specific fields of a POJO

王林
王林forward
2024-02-08 22:51:22803browse

php editor Zimo will introduce you to the Bean Validation API in this article, and focus on one of its important features - dynamically instructing the validator to ignore specific constraint annotations on specific POJO fields. The Bean Validation API is a standard way to perform data validation in Java applications. It provides a simple and flexible way to define and apply validation rules through annotations. Dynamically instructing the validator to ignore constraint annotations on specific fields provides developers with greater flexibility and controllability, allowing the validation rules to be flexibly adjusted in specific scenarios, thereby improving the maintainability and expansion of the code. sex. Next, we will delve into how to use this feature and practical application scenarios.

Question content

I have a pojo where some fields are annotated with @notempty:

public class sampleforminputdto {

  @notempty
  private string textarea;

  private int myint = 0;

  @notempty
  private string mytext = "somevalue";

  public string gettextarea() {
    return textarea;
  }

  public void settextarea(string textarea) {
    this.textarea = textarea;
  }
}

The purpose is to check the fields to ensure they contain a value, i.e. are not null and are not empty.

If I create an instance of sampleforminputdto using the parameterless constructor, the field textarea will initially be null and therefore should and does fail validation as expected.

SampleFormInputDTO sampleFormInputDTO = new SampleFormInputDTO();

ValidatorFactory validatorFactory =
    Validation.byDefaultProvider()
        .configure()
        .messageInterpolator(new ParameterMessageInterpolator())
        .buildValidatorFactory();

Validator validator = validatorFactory.getValidator(sampleFormInputDTO);

Set<ConstraintViolation<SampleFormInputDTO>> violationSet = validator.validate();

I was wondering if it is possible to dynamically/programmatically instruct a validator instance not to validate a specific constraint annotation for a specific field?

Let's say I've determined that, as part of processing a rest api call, I want fields of type sampleforminputdto to dynamically allow empty strings for textarea, but only for that specific field. Does not affect any constraint annotations that may exist on other fields in the same pojo.

is it possible?

Workaround

You may want to look at Authentication Groups.

public class sampleforminputdto {

  @notempty(groups = group1.class)
  private string textarea;

  private int myint = 0;

  @notempty
  private string mytext = "somevalue";

  public string gettextarea() {
    return textarea;
  }

  public void settextarea(string textarea) {
    this.textarea = textarea;
  }
}

You can then control which constraints are included in the validation and which are not included in the validation, for example:

validator.validate(sampleforminputdto);

Only the mytext attribute will be checked, but it will look like:

validator.validate(sampleFormInputDTO, Group1.class, Default.class);

will verify both.

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