如何从ConstraintViolationException获取查询参数名称 [英] How to get query parameter name from ConstraintViolationException
问题描述
我有一种服务方法:
@GetMapping(path = "/api/some/path", produces = MediaType.APPLICATION_JSON_VALUE)
public ResponseEntity<?> getWhatever(@RequestParam(value = "page-number", defaultValue = "0") @Min(0) Integer pageNumber, ...
如果API的调用者没有为page-number查询参数提交正确的值，则会引发javax.ConstraintViolationexception.异常消息将如下所示:
If the caller of an API doesn't submit a proper value for page-number query parameter, javax.ConstraintViolationexception is being raised. The message of the exception would read smth like:
getWhatever.pageNumber must be equal or greater than 0
在响应正文中，我想显示以下消息:
In the response body, I would like to have this message instead:
page-number must be equal or greater than 0
我希望我的消息具有查询参数的名称，而不是参数的名称.恕我直言，包括参数名称在内的都是公开实现细节.
I want my message to have the name of a query parameter, not the name of the argument. IMHO, including the name of the argument is exposing the implementation details.
问题是，我找不到带有查询参数名称的对象.似乎ConstraintViolationException没有它.
The problem is, I cannot find an object that is carrying query parameter name. Seems like the ConstraintViolationException doesn't have it.
我正在春季引导中运行我的应用.
I am running my app in spring-boot.
任何帮助将不胜感激.
P.S .:我去过其他声称可以解决问题的类似话题，但实际上它们都没有.
P.S.: I have been to the other similar threads that claim to solve the problem, none of them actually do in reality.
推荐答案
这是我在Spring-boot 2.0.3中使其工作的方式:
Here is how I made it work in spring-boot 2.0.3:
我必须在spring-boot中覆盖并禁用ValidationAutoConfiguration:
I had to override and disable ValidationAutoConfiguration in spring-boot:
import org.springframework.boot.validation.MessageInterpolatorFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Lazy;
import org.springframework.core.env.Environment;
import org.springframework.validation.beanvalidation.LocalValidatorFactoryBean;
import org.springframework.validation.beanvalidation.MethodValidationPostProcessor;
import javax.validation.Validator;
@Configuration
public class ValidationConfiguration {
public ValidationConfiguration() {
}
@Bean
public static LocalValidatorFactoryBean validator() {
LocalValidatorFactoryBean factoryBean = new LocalValidatorFactoryBean();
factoryBean.setParameterNameDiscoverer(new CustomParamNamesDiscoverer());
MessageInterpolatorFactory interpolatorFactory = new MessageInterpolatorFactory();
factoryBean.setMessageInterpolator(interpolatorFactory.getObject());
return factoryBean;
}
@Bean
public static MethodValidationPostProcessor methodValidationPostProcessor(Environment environment, @Lazy Validator validator) {
MethodValidationPostProcessor processor = new MethodValidationPostProcessor();
boolean proxyTargetClass = (Boolean) environment.getProperty("spring.aop.proxy-target-class", Boolean.class, true);
processor.setProxyTargetClass(proxyTargetClass);
processor.setValidator(validator);
return processor;
}
}
CustomParamNamesDiscoverer位于同一程序包中，它几乎是DefaultParameterNameDiscoverer的复制粘贴，它是spring-boot的param名称发现器的默认实现:
CustomParamNamesDiscoverer sits in the same package and it is a pretty much a copy-paste of DefaultParameterNameDiscoverer, spring-boot's default implementation of param name discoverer:
import org.springframework.core.*;
import org.springframework.util.ClassUtils;
public class CustomParameterNameDiscoverer extends PrioritizedParameterNameDiscoverer {
private static final boolean kotlinPresent = ClassUtils.isPresent("kotlin.Unit", CustomParameterNameDiscoverer.class.getClassLoader());
public CustomParameterNameDiscoverer() {
if (kotlinPresent) {
this.addDiscoverer(new KotlinReflectionParameterNameDiscoverer());
}
this.addDiscoverer(new ReqParamNamesDiscoverer());
this.addDiscoverer(new StandardReflectionParameterNameDiscoverer());
this.addDiscoverer(new LocalVariableTableParameterNameDiscoverer());
}
}
我希望它保持完整无缺(您甚至可以在其中看到kotlin支票)，唯一的补充是:
我正在将ReqParamNamesDiscoverer的实例添加到发现者的链接列表中.请注意，添加顺序在这里很重要.
I wanted it to remain pretty much intact (you can see even kotlin checks in there) with the only addition:
I am adding an instance of ReqParamNamesDiscoverer to the linked lists of discoverers. Note that the order of addition does matter here.
这是源代码:
import com.google.common.base.Strings;
import org.springframework.core.ParameterNameDiscoverer;
import org.springframework.lang.Nullable;
import org.springframework.web.bind.annotation.RequestParam;
import java.lang.reflect.Constructor;
import java.lang.reflect.Executable;
import java.lang.reflect.Method;
import java.lang.reflect.Parameter;
public class ReqParamNamesDiscoverer implements ParameterNameDiscoverer {
public ReqParamNamesDiscoverer() {
}
@Override
@Nullable
public String[] getParameterNames(Method method) {
return doGetParameterNames(method);
}
@Override
@Nullable
public String[] getParameterNames(Constructor<?> constructor) {
return doGetParameterNames(constructor);
}
@Nullable
private static String[] doGetParameterNames(Executable executable) {
Parameter[] parameters = executable.getParameters();
String[] parameterNames = new String[parameters.length];
for (int i = 0; i < parameters.length; ++i) {
Parameter param = parameters[i];
if (!param.isNamePresent()) {
return null;
}
String paramName = param.getName();
if (param.isAnnotationPresent(RequestParam.class)) {
RequestParam requestParamAnnotation = param.getAnnotation(RequestParam.class);
if (!Strings.isNullOrEmpty(requestParamAnnotation.value())) {
paramName = requestParamAnnotation.value();
}
}
parameterNames[i] = paramName;
}
return parameterNames;
}
}
如果用RequestParam注释对参数进行注释，则我正在检索value属性并将其作为参数名称返回.
If parameter is annotated with RequestParam annotation, I am retrieving the value attribute and return it as a parameter name.
接下来的事情是禁用自动验证配置，以某种方式，没有它就无法工作.这个注解可以解决问题:
@SpringBootApplication(exclude = {ValidationAutoConfiguration.class})
The next thing was disabling auto validation config, somehow, it doesn't work without it. This annotation does the trick though:
@SpringBootApplication(exclude = {ValidationAutoConfiguration.class})
此外，您还需要为ConstraintValidationException提供一个自定义处理程序:
Also, you need to have a custom handler for your ConstraintValidationException :
@ResponseStatus(HttpStatus.BAD_REQUEST)
@ExceptionHandler(ConstraintViolationException.class)
public ErrorDTO handleConstraintViolationException(ConstraintViolationException ex) {
Map<String, Collection<String>> errors = new LinkedHashMap<>();
ex.getConstraintViolations().forEach(constraintViolation -> {
String queryParamPath = constraintViolation.getPropertyPath().toString();
log.debug("queryParamPath = {}", queryParamPath);
String queryParam = queryParamPath.contains(".") ?
queryParamPath.substring(queryParamPath.indexOf(".") + 1) :
queryParamPath;
String errorMessage = constraintViolation.getMessage();
Collection<String> perQueryParamErrors = errors.getOrDefault(queryParam, new ArrayList<>());
perQueryParamErrors.add(errorMessage);
errors.put(queryParam, perQueryParamErrors);
});
return validationException(new ValidationException("queryParameter", errors));
}
ValidationException东西是我处理验证错误的自定义方式，简而言之，它会产生错误DTO，并将其与所有验证错误消息一起序列化为JSON.
ValidationException stuff is my custom way of dealing with validation errors, in a nutshell, it produces an error DTO, which will be serialized into JSON with all the validation error messages.
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