来自其他字段 javax.validation 条件的选项的字段验证答案

【问题标题】：Field validation from options on condition from other field javax.validation来自其他字段 javax.validation 条件的选项的字段验证
【发布时间】：2019-04-11 12:16:01
【问题描述】：

如果存在另一个字段，我需要执行字段验证（它可以是值之一）。

import javax.validation.*;

class Person {

    @NotBlank
    private String name;

    private Long groupId;

    @Valid // if group id is not null, select one from available.
    private String specialization;

    // getters, setters.
}

class PersonValidaionLogic {

    @Autowired
    private SpecializationService specializationService;

    public void validatePerson(final Person person) {
        Long groupId = person.getGroupId();
        if (groupId != null) {
            Set<String> availableSpecializations = specializationService.getByGroupId(groupId);
            if (!availableSpecializations.contains(specialization)) {
                addValidationError("specialization is not valid");
            }
        }
    }
}

有一个nice answer on how to validate multiple fields in a class with conditions on each other。

如何将specializationService 和groupId 传递给验证器。

【问题讨论】：

标签： java validation bean-validation

【解决方案1】：

随时分享您的解决方案或想法！我就是这样解决这个问题的。

我在我的问题中使用了链接中的想法，但方式更简单。

首先，我解决了一个问题how to pass a Spring component or service into validator。我使用了一个包含对服务的静态引用的组件。

其次，我验证了链接中描述的整个对象。

这是代码！

1) 创建注解@PersonConstraint 并放入Person 类。这可能会有所帮助https://www.baeldung.com/javax-validation-method-constraints

@Target({ TYPE })
@Retention(RUNTIME)
@Constraint(validatedBy = PersonValidator.class)
public @interface PersonConstraint {

    String message() default "Specialization is not valid";

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

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

    CaseMode value();
}

2) 持有对服务的静态引用的组件。

@Component // Spring component.
class ServiceHolderComponent {

    private static SpecializationService SPECIALIZATION_SERVICE;

    @Autowired
    public ServiceHolderComponent(final SpecializationService specializationService) {
        GROUP_SERVICE = Validate.notNull(groupService); //apache lib
    }

    public static SpecializationService getSpecializationService() {
        return SPECIALIZATION_SERVICE;
    }
}

3) 和人员验证器

public class PersonValidator implements ConstraintValidator<PersonConstraint, Person> {

    private final SpecializationService specializationService;

    public UserDynamicEnumValidator() {
        this(ServiceHolderComponent.getSpecializationService());
    }

    public UserDynamicEnumValidator(final SpecializationService specializationService) {
        this.specializationService = specializationService;
    }

    @Override
    public boolean isValid(final Person person, final ConstraintValidatorContext context) {
        final Long groupId = person.getGroupId();
        if (groupId == null) {
            return true; // We consider it valid.
        }

        final String specialization = person.getSpecializat();
        if (StringUtils.isEmpty(specialization)) {
            return true; // We consider it valid.
        }

        // I changed the code of the service, so it returns a set of strings - projection query and collectors to set.
        final Set<String> availableSpecializationValuesByGroup = specializationService.findByValue(groupId);

        if (!availableSpecializationValuesByGroup.contains(specialization)) {
            // To display custom message
            context.disableDefaultConstraintViolation();
            context.buildConstraintViolationWithTemplate("Specialization is not valid").addConstraintViolation();
            return false;
        }

        return true;
    }
}

要显示custom message in validator，请检查此

【讨论】：