模型注释可以验证两个字段吗

Question

I have this model class

@Document(collection = "MyClass")
public class MyClass implements Persistable<UUID> {

    @NotEmpty(groups = { Create.class})
    private String field1;

    @NotEmpty(groups = { Create.class})
    private String field2;
}

Now during Create, I want to check that either field1 is empty or field2 is but both should not be empty

Can I do this through preexisting annotations or custom annotations (that implement ConstraintValidator) or will I have to resort to validating in my service layer

Answer 1

You can create a custom annotation and use that annotation to validate in the Create class.

@CustomAnnotation(field1 = "field1", field2 = "field2")
class Create  {

    private String field1;
    private String field2;
}

Custom Annotation:

@Target({TYPE, ANNOTATION_TYPE})
@Retention(RetentionPolicy.RUNTIME)
@Constraint(validatedBy = CustomAnnotationValidator.class)
@Documented
public @interface CustomAnnotation {
    String message() default "One of field1 or field2 required";  //can make use of properties file to interpolate message

    String field1();    
    String field2();

}

then in the validator impl:

public class CustomAnnotationValidator implements ConstraintValidator<CustomAnnotation, Object> {

private String field1Holder;
private String field2Holder;

@Override
public void initialize(CustomAnnotation constraintAnnotation) {
    field1Holder = constraintAnnotation.field1();
    field2Holder = constraintAnnotation.field2();
}

@Override
public boolean isValid(Object value, ConstraintValidatorContext context) {
    try {
        final String field1 = BeanUtils.getProperty(value, field1Holder);
        final String field2 = BeanUtils.getProperty(value, field2Holder);
        return !(field1 == null && field2 == null); //your validation logic
    } catch (Exception e) {
        log.error("Error validating object", e);
        return false;
    }
}