Question

我紧跟着this blog的帖子，尝试实现一个自定义验证器来验证复合主键约束，但失败并显示：

javax.validation.ValidationException: HV000064: Unable to instantiate ConstraintValidator: com.directory.domain.model.validators.StorePoolValidator.
    at com.directory.domain.repositories.StorePoolRepositoryTest.shouldReturnPoolByStore(StorePoolRepositoryTest.java:30)
Caused by: java.lang.NoSuchMethodException: com.directory.domain.model.validators.StorePoolValidator.<init>()
    at com.directory.domain.repositories.StorePoolRepositoryTest.shouldReturnPoolByStore(StorePoolRepositoryTest.java:30)

这是验证器的注释界面的代码：

import javax.validation.Constraint;
import javax.validation.Payload;
import java.lang.annotation.Retention;
import java.lang.annotation.Target;

import static java.lang.annotation.ElementType.FIELD;
import static java.lang.annotation.RetentionPolicy.RUNTIME;

@Retention(RUNTIME)
@Target({FIELD})
@Constraint(validatedBy = StorePoolValidator.class)
public @interface UniqueStorePoolConstraint {
    String message() default "Store pool validation failed";

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

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

这是验证器类：

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import java.util.List;

public class StorePoolValidator implements ConstraintValidator<UniqueStorePoolConstraint, StorePoolId> {

    private StorePoolRepository storePoolRepository;

    public StorePoolValidator(StorePoolRepository storePoolRepository) {
        this.storePoolRepository = storePoolRepository;
    }

    @Override
    public void initialize(UniqueStorePoolConstraint constraintAnnotation) {

    }

    @Override
    public boolean isValid(StorePoolId id, ConstraintValidatorContext context) {
        final List<StorePool> storePools = storePoolRepository.findAllByStoreNumber(id.getThirdNumber());

        return storePools.isEmpty();
    }
}

这是实体类：

@Entity
@Getter
@Setter
@Builder
@AllArgsConstructor
@Table(name = "STORE_POOLS")
public class StorePool implements Serializable {

    public StorePool() {
    }

    @EmbeddedId
    @UniqueStorePoolConstraint
    private StorePoolId id;
}

并设置其主键类：

import javax.persistence.Column;
import javax.persistence.Embeddable;
import javax.validation.constraints.NotNull;
import java.io.Serializable;

@Getter
@Setter
@Builder
@ToString
@Embeddable
@EqualsAndHashCode
@AllArgsConstructor
@NoArgsConstructor(access = AccessLevel.PROTECTED)
public class StorePoolId implements Serializable {

    @Column(name = "pool", nullable = false)
    @NotNull
    private Integer pool;

    @Column(name = "third_number", nullable = false)
    @NotNull
    private Integer thirdNumber;
}

我尝试运行以下测试：

@RunWith(SpringRunner.class)
@DataJpaTest
public class StorePoolRepositoryTest {

    @Autowired
    private StorePoolRepository storePoolRepository;

    @Autowired
    private TestEntityManager entityManager;

    @Test
    public void shouldReturnPoolByStore() {
        final StorePool storePool = StorePoolBuilder.buildStorePool(1, 1);
        entityManager.persist(storePool);
        entityManager.flush();

        final List<StorePool> storePools = storePoolRepository.findAllByStoreNumber(1);

        assertThat(storePools).containsExactly(storePool);
    }
}

我想念什么？谢谢。

Answer 1

抱歉在讨论中迟到了。

首先创建一个ContextProvider，它是你需要的bean的提供者。

@Component
public class ContextProvider implements ApplicationContextAware {

    private static ApplicationContext applicationContext;

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        ContextProvider.applicationContext = applicationContext;
    }

    public static Object getBean(Class cls) {
        return ContextProvider.applicationContext.getBean(cls);
    }

}

现在你可以像这样拥有 bean：

ContextProvider.getBean(StorePoolRepository.class);

这解决了 NPE，您可以使用任何组件进行验证。

在您的情况下 StorePoolValidator，

@Service
public class StorePoolValidator implements ConstraintValidator<UniqueStorePoolConstraint, StorePoolId> {

    private StorePoolRepository storePoolRepository;

    @Override
    public void initialize(UniqueStorePoolConstraint constraintAnnotation) {
         this.storePoolRepository = (StorePoolRepository) ContextProvider.getBean(StorePoolRepository.class) 
    }

    @Override
    public boolean isValid(StorePoolId id, ConstraintValidatorContext context) {
        final List<StorePool> storePools = storePoolRepository.findAllByStoreNumber(id.getThirdNumber());

        return storePools.isEmpty();
    }
}

就是这样。

Answer 2

默认情况下，StorePoolValidator需要添加一个构造函数为空才能初始化验证器。

public StorePoolValidator() {
}

更新

为了使用存储库，您可以将Validator作为服务添加。那么答案是这样的：

@Service
public class StorePoolValidator implements ConstraintValidator<UniqueStorePoolConstraint, StorePoolId> {

    @Autowired
    private StorePoolRepository storePoolRepository;

    @Override
    public void initialize(UniqueStorePoolConstraint constraintAnnotation) {

    }

    @Override
    public boolean isValid(StorePoolId id, ConstraintValidatorContext context) {
        final List<StorePool> storePools = storePoolRepository.findAllByStoreNumber(id.getThirdNumber());

        return storePools.isEmpty();
    }
}

Answer 3

Spring框架自动检测实现ConstraintValidator接口的所有类。该框架实例化它们并连接所有依赖项，就像该类是常规的Spring bean。因此，您无需放置@Service和@Autowired批注。 More details here.

javax.validation.ValidationException：HV000064：无法实例化ConstraintValidator

3 个答案: