使用JSR-303和Spring的Validator的组合为Spring引导端点实现自定义验证逻辑

Question

我尝试使用JSR-303 Bean Validation API和Spring's Validator的组合为弹簧启动端点实现一些自定义验证逻辑。

基于Validator类图，似乎可以扩展CustomValidatorBean，SpringValidatorAdapter或LocalValidatorFactoryBean中的一个，以将一些自定义验证逻辑添加到重写方法validate(Object target, Errors errors)中

但是，如果我创建一个验证器来扩展这三个类中的任何一个并使用@InitBinder注册它，则永远不会调用其validate(Object target, Errors errors)方法，也不会执行验证。如果我删除@InitBinder，则默认的弹簧验证程序会执行JSR-303 Bean Validation。

休息控制器：

@RestController
public class PersonEndpoint {

    @InitBinder("person")
    protected void initBinder(WebDataBinder binder) {
        binder.setValidator(new PersonValidator());
    }

    @RequestMapping(path = "/person", method = RequestMethod.PUT)
    public ResponseEntity<Person> add(@Valid @RequestBody Person person) {

        person = personService.save(person);
        return ResponseEntity.ok().body(person);
    }
}

自定义验证器：

public class PersonValidator extends CustomValidatorBean {

    @Override
    public boolean supports(Class<?> clazz) {
        return Person.class.isAssignableFrom(clazz);
    }

    @Override
    public void validate(Object target, Errors errors) {
        super.validate(target, errors);
        System.out.println("PersonValidator.validate() target="+ target +" errors="+ errors);
    }

}

如果我的验证器实现org.springframework.validation.Validator，则会调用其validate(Object target, Errors errors)方法，但在此之前不会执行JSR-303 Bean Validation。我可以实现我的自定义JSR-303验证，类似于SpringValidatorAdapter实现其JSR-303 Bean Validation的方式，但必须有一种方法来扩展它：

    @Override
    public void validate(Object target, Errors errors) {
        if (this.targetValidator != null) {
            processConstraintViolations(this.targetValidator.validate(target), errors);
        }
    }

我已经研究过使用自定义JSR-303约束来避免一起使用org.springframework.validation.Validator，但必须有一种方法可以使自定义验证器工作。

Spring validation documentation在结合两者时并不是非常清楚：

  

应用程序还可以为每个DataBinder实例注册其他Spring Validator实例，如第9.8.3节“配置DataBinder”中所述。这可以用于在不使用注释的情况下插入验证逻辑。

然后它接触到配置多个Validator实例

  

还可以通过dataBinder.addValidators和dataBinder.replaceValidators为DataBinder配置多个Validator实例。将全局配置的Bean验证与在DataBinder实例上本地配置的Spring验证器组合时，这非常有用。见???。

我使用的是Spring boot 1.4.0。

Answer 1

Per @ M.Deinum - 使用addValidators（）而不是setValidator（）就可以了。我也同意使用JSR-303，@ AssertTrue基于方法的注释专门用于交叉字段验证，可能是一个更清晰的解决方案。代码示例位于https://github.com/pavelfomin/spring-boot-rest-example/tree/feature/custom-validator。在该示例中，中间名称验证通过自定义弹簧验证器执行，而姓氏验证由默认的jsr 303验证器处理。

Answer 2

扩展LocalValidatorFactoryBean可以解决这个问题，你可以覆盖这个类中的validate方法，给出你想要的任何行为。

在我的情况下，我需要在同一个Controller中的不同方法中对同一模型使用JSR-303 AND自定义验证器，通常建议使用@InitBinder，但这对我的情况来说还不够，因为InitBinder在Model和验证器（如果您使用@RequestBody InitBinder仅适用于一个模型，每个控制器使用一个验证器）。

控制器

@RestController
public class LoginController {

    @PostMapping("/test")
    public Test test(@Validated(TestValidator.class) @RequestBody Test test) {
        return test;
    }

    @PostMapping("/test2")
    public Test test2(@Validated @RequestBody Test test) {
        return test;
    }
}

自定义验证器

public class TestValidator implements org.springframework.validation.Validator {

    @Override
    public boolean supports(Class<?> clazz) {
        return Test.class.isAssignableFrom(clazz);
    }

    @Override
    public void validate(Object target, Errors errors) {
        Test test = (Test) target;
        errors.rejectValue("field3", "weird");
        System.out.println(test.getField1());
        System.out.println(test.getField2());
        System.out.println(test.getField3());
     }
}

要验证的类

public class Test {

    @Size(min = 3)
    private String field2;

    @NotNull
    @NotEmpty
    private String field1;

    @NotNull
    @Past
    private LocalDateTime field3;

    //...
    //getter/setter
    //...
}

CustomLocalValidatorFactoryBean

public class CustomLocalValidatorFactoryBean extends LocalValidatorFactoryBean {

    private Logger logger = LoggerFactory.getLogger(this.getClass());

    @Override
    public void validate(@Nullable Object target, Errors errors, @Nullable Object... validationHints) {
        Set<Validator> concreteValidators = new LinkedHashSet<>();
        Set<Class<?>> interfaceGroups = new LinkedHashSet<>();
        extractConcreteValidatorsAndInterfaceGroups(concreteValidators, interfaceGroups, validationHints);
        proccessConcreteValidators(target, errors, concreteValidators);
        processConstraintViolations(super.validate(target, interfaceGroups.toArray(new Class<?>[interfaceGroups.size()])), errors);
    }

    private void proccessConcreteValidators(Object target, Errors errors, Set<Validator> concreteValidators) {
        for (Validator validator : concreteValidators) {
            validator.validate(target, errors);
        }
    }

    private void extractConcreteValidatorsAndInterfaceGroups(Set<Validator> concreteValidators, Set<Class<?>> groups, Object... validationHints) {
        if (validationHints != null) {
            for (Object hint : validationHints) {
                if (hint instanceof Class) {
                    if (((Class<?>) hint).isInterface()) {
                        groups.add((Class<?>) hint);
                    } else {
                        Optional<Validator> validatorOptional = getValidatorFromGenericClass(hint);
                        if (validatorOptional.isPresent()) {
                            concreteValidators.add(validatorOptional.get());
                        }
                    }
                }
            }
        }
    }

    @SuppressWarnings("unchecked")
    private Optional<Validator> getValidatorFromGenericClass(Object hint) {
        try {
            Class<Validator> clazz = (Class<Validator>) Class.forName(((Class<?>) hint).getName());
            return Optional.of(clazz.newInstance());
        } catch (ClassNotFoundException | InstantiationException | IllegalAccessException e) {
            logger.info("There is a problem with the class that you passed to "
                    + " @Validated annotation in the controller, we tried to "
                    + " cast to org.springframework.validation.Validator and we cant do this");
        }
        return Optional.empty();
    }

}

配置应用程序

@SpringBootApplication
public class Application {

    public static void main(String[] args) {
        SpringApplication.run(Application.class, args);
    }

    @Bean
    public javax.validation.Validator localValidatorFactoryBean() {
        return new CustomLocalValidatorFactoryBean();
    }
}

输入到/test端点：

{
    "field1": "",
    "field2": "aaaa",
    "field3": "2018-04-15T15:10:24"
}

/test端点的输出：

{
    "timestamp": "2018-04-16T17:34:28.532+0000",
    "status": 400,
    "error": "Bad Request",
    "errors": [
        {
            "codes": [
                "weird.test.field3",
                "weird.field3",
                "weird.java.time.LocalDateTime",
                "weird"
            ],
            "arguments": null,
            "defaultMessage": null,
            "objectName": "test",
            "field": "field3",
            "rejectedValue": "2018-04-15T15:10:24",
            "bindingFailure": false,
            "code": "weird"
        },
        {
            "codes": [
                "NotEmpty.test.field1",
                "NotEmpty.field1",
                "NotEmpty.java.lang.String",
                "NotEmpty"
            ],
            "arguments": [
                {
                    "codes": [
                        "test.field1",
                        "field1"
                    ],
                    "arguments": null,
                    "defaultMessage": "field1",
                    "code": "field1"
                }
            ],
            "defaultMessage": "Não pode estar vazio",
            "objectName": "test",
            "field": "field1",
            "rejectedValue": "",
            "bindingFailure": false,
            "code": "NotEmpty"
        }
    ],
    "message": "Validation failed for object='test'. Error count: 2",
    "path": "/user/test"
}

输入到/test2端点：

{
    "field1": "",
    "field2": "aaaa",
    "field3": "2018-04-15T15:10:24"
}

输出到/test2端点：

{
    "timestamp": "2018-04-16T17:37:30.889+0000",
    "status": 400,
    "error": "Bad Request",
    "errors": [
        {
            "codes": [
                "NotEmpty.test.field1",
                "NotEmpty.field1",
                "NotEmpty.java.lang.String",
                "NotEmpty"
            ],
            "arguments": [
                {
                    "codes": [
                        "test.field1",
                        "field1"
                    ],
                    "arguments": null,
                    "defaultMessage": "field1",
                    "code": "field1"
                }
            ],
            "defaultMessage": "Não pode estar vazio",
            "objectName": "test",
            "field": "field1",
            "rejectedValue": "",
            "bindingFailure": false,
            "code": "NotEmpty"
        }
    ],
    "message": "Validation failed for object='test'. Error count: 1",
    "path": "/user/test2"
}

我希望这有帮助。