如何在 Spring 中替换 javax.validation.Valid 注释的实现？

Question

假设我不想使用 JSR 303 来验证我的 bean。当bean标记为@Valid时，是否可以实现Spring将使用的自定义验证器？

如果我的自定义验证器是 Spring 组件那就太好了

Answer 1

@fedor.belov

我在另一个问题中详细说明了这个问题。在我的需要中，我想保留 JSR-303 并使自定义验证器正常工作，但您可以更改我的示例代码以满足您的需要。

这个问题可以通过扩展 LocalValidatorFactoryBean 来解决，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 的不同方法中使用 JSR-303 和自定义验证器，通常建议使用 @InitBinder，但对于我的情况来说这还不够，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"
}

来自/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"
}

Original answer with original question.

希望对你有所帮助。

Answer 2

您必须实现Validator 接口并将实现标记为@Component。然后您可以使用 @InitBinder 注释绑定您的自定义验证器。像这样的：

@Component
public class MyCustomValidator implements Validator
{

    @Override
    public boolean supports(Class<?> clazz)
    {
        // your custom logic
    }

    @Override
    public void validate(Object target, Errors errors)
    {
        // your custom logic
    }
}

用注解绑定它：

@Controller
public class MyController
{
    @Autowired
    private MyCustomValidator validator;

    @InitBinder
    protected void initBinder(final WebDataBinder binder)
    {
        binder.addValidators(validator);
    }
}