处理从自定义转换器抛出的Spring Boot REST中的异常

Question

我是Spring Boot的新手，但经过几个小时的阅读关于Spring Boot REST中异常handlig的帖子和博客，没有人写任何关于处理从自定义Converter抛出的异常的事情，我决定写这里。

我开发了基于Spring Boot的小型REST应用程序，它只是从IntelliJ生成的。示例性方法看起来像这样

@RestController
@RequestMapping("/resources")
public class CVResourceService {

    private final TechnologyRepository technologyRepository;
    private final ProjectRepository projectRepository;

    @Autowired
    public CVResourceService(TechnologyRepository technologyRepository,     ProjectRepository projectRepository) {
        this.technologyRepository = technologyRepository;
        this.projectRepository = projectRepository;
    }

    @RequestMapping(value = "/users/{guid}/projects/langs/{lang}", method = RequestMethod.GET, produces = MediaType.APPLICATION_JSON_VALUE)
    @ResponseBody
    public Collection getUserProjects(@PathVariable("guid") GUID userGUID,         @PathVariable("lang") Language language) {
        return  ProjectDTOAssembler.toDTOs(projectRepository.findOne(userGUID, language));
    }
}

因为guid和lang都是字符串，我希望这些信息是从同一个开始的强类型，我创建了GUID和Language类型的简单转换器，并在Application类中注册它：

public final class GUIDConverter implements Converter{

    @Override
    public GUID convert(String source) {
        return GUID.fromString(source);
    }
}

public class LanguageConverter implements Converter{

    @Override
    public Language convert(String source) {
        Language language = Language.of(source);
        if (language == null) { throw new WrongLanguagePathVariableException(); }

        return language;
    }
}

GUID从方法工厂抛出异常，

...
public static GUID fromString(String string) {
    String[] components = string.split("-");

    if (components.length != 5)
        throw new IllegalArgumentException("Invalid GUID string: " + string);

    return new GUID(string);
}
...

Language返回null，然后我从转换器中抛出自定义异常。在应用程序中注册：

@SpringBootApplication
public class Application extends WebMvcConfigurerAdapter {

    @Override
    public void addFormatters(FormatterRegistry registry) {
        registry.addConverter(new GUIDConverter());
        registry.addConverter(new LanguageConverter());
    }

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

使用@ResponseStatus，@ControllerAdvice和@ExpectationHandler处理所有类型的处理异常我无法在Controller中捕获转换器的异常来重写（或更好地映射）json错误响应原始字段的“status”，“error”，“exception”和“message”我的价值观。可能是因为在调用REST方法之前抛出了异常。我尝试用ResponseEntityExceptionHandler解决方案，但它根本不起作用。

对于请求http://localhost:8080/resources/users/620e643f-406f-4c69-3f4c-3f2c303f3f3f/projects/langs/end，正确的语言是en，异常的响应是：

{
    "timestamp": 1458812172976,
    "status": 400,
    "error": "Bad Request",
    "exception":   "org.springframework.web.method.annotation.MethodArgumentTypeMismatchException",
    "message": "Failed to convert value of type [java.lang.String] to required type [com.cybercom.cvdataapi.domain.Language]; nested exception is org.springframework.core.convert.ConversionFailedException: Failed to convert from type [java.lang.String] to type [@org.springframework.web.bind.annotation.PathVariable com.cybercom.cvdataapi.domain.Language] for value 'end'; nested exception is com.cybercom.cvdataapi.interfaces.rest.converter.WrongLanguagePathVariableException",
    "path": "/resources/users/620e643f-406f-4c69-3f4c-3f2c303f3f3f/projects/langs/end"

}

自定义异常仅在message字段的最后位置，但当然应该与我的自定义消息交换。自定义排除应该在exception字段，现在是Spring异常。这当然是目标，不知道如何在这种背景下实现它。

请解决我的问题，捕获从转换器抛出的异常并映射它们的方式，因为它可以使用@ControllerAdvice和从控制器抛出的异常。 Thx提前。

Answer 1

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