spring - 使用 Spring 的 JSR-303 约束验证器中的依赖注入(inject)失败

Question

我和 here 有同样的问题和 here但还没有找到解决方案。

所以我的示例测试项目将显示整个相关配置和代码:

约束注解:

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

    String message();

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

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

注释 PoJo:

public class Foo {

    @FooValid(message = "Test failed")
    private Integer test;
    [...]
}

带有@Validated 的注解服务:

@Service
@Validated
public class FooService {

    private final Test test;

    @Autowired
    public FooService(final Test test) {
        this.test = test;
    }

    public void foo(@Valid final Foo foo) {
        this.test.test(foo);
    }
}

JSR-303 约束验证器:

public class FooValidator implements ConstraintValidator<FooValid, Integer> {

    @Autowired
    private ValidationService validationService;

    @Override
    public void initialize(final FooValid constraintAnnotation) {
        // TODO Auto-generated method stub

    }

    @Override
    public boolean isValid(final Integer value, final ConstraintValidatorContext context) {
        // this.validationService is always NULL!
        Assert.notNull(this.validationService, "the validationService must not be null");
        return false;
    }

}

注入(inject)验证服务:

@Service
public class ValidationService {

    public void test(final Foo foo) {
        System.out.println(foo);
    }
}

Spring Boot 应用及配置:

@Configuration
@ComponentScan
@EnableAutoConfiguration
public class Application {

    public static void main(final String[] args) {
        final ConfigurableApplicationContext context = SpringApplication.run(Application.class, args);
        final FooService service = context.getBean(FooService.class);
        service.foo(new Foo());
    }

    @Bean
    public static LocalValidatorFactoryBean validatorFactory() {
        return new LocalValidatorFactoryBean();
    }

    @Bean
    public static MethodValidationPostProcessor validationPostProcessor() {
        return new MethodValidationPostProcessor();
    }

}

相关的maven pom:

<parent>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-parent</artifactId>
    <version>1.1.9.RELEASE</version>
    <relativePath/>
</parent>

<dependencies>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter</artifactId>
    </dependency>
    <dependency>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-test</artifactId>
        <scope>test</scope>
    </dependency>
    <dependency>
        <groupId>org.hibernate</groupId>
        <artifactId>hibernate-validator</artifactId>
    </dependency>
</dependencies>

<properties>
    <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    <start-class>demo.Application</start-class>
    <java.version>1.7</java.version>
</properties>

<build>
    <plugins>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
        </plugin>
    </plugins>
</build>

我正在使用 LocalValidatorFactoryBean 默认 SpringConstraintValidatorFactory .
但是为什么依赖注入(inject)在 ConstraintValidator 中不起作用并且 ValidationService 无法 Autowiring ？

顺便说一句，如果我不在服务中使用@Validated，则在 spring 或 javax Validator 接口(interface)的对面注入(inject)并手动调用“validator.validate”，依赖注入(inject)将起作用。但我不想在每个服务中手动调用 validate 方法。

非常感谢您的帮助:)

Answer 1

我在 Spring Boot 环境中遇到了同样的问题，我发现 Hibernate 内部实现代替了配置的 Spring 实现。当应用程序启动时，调试器发现了 Spring 的工厂，但后来在运行时出现了 Hibernate 的工厂。经过一番调试，得出的结论是方法验证后处理器 得到了内部的。因此，我将其配置如下:

@Bean
public Validator validator() {
    return new LocalValidatorFactoryBean();
}

@Bean
public MethodValidationPostProcessor methodValidationPostProcessor(Validator validator) {
    MethodValidationPostProcessor methodValidationPostProcessor = new MethodValidationPostProcessor();
    methodValidationPostProcessor.setValidator(validator);
    return methodValidationPostProcessor;
}

请注意验证器的 setter - 它完成了这项工作。