使用 Spring Data REST 处理自定义异常 (i18n)

Question

我正在使用 Spring Boot 1.5.4 和 Spring JPA、Spring Data REST、HATEOAS... 我正在寻找一种最佳实践（Spring 方式）来自定义异常 Spring Data REST 正在管理添加 i18n 支持。

我将 MessageException (https://github.com/spring-projects/spring-data-rest/blob/master/spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/support/ExceptionMessage.java) 类作为起点。

一个典型的 Spring Data REST 异常非常好：

    {
    "timestamp": "2017-06-24T16:08:54.107+0000",
    "status": 500,
    "error": "Internal Server Error",
    "exception": "org.springframework.dao.InvalidDataAccessApiUsageException",
    "message": "org.hibernate.TransientPropertyValueException: Not-null property references a transient value - transient instance must be saved beforeQuery current operation : com.test.server.model.workflows.WorkSession.checkPoint -> com.test.server.model.checkpoints.CheckPoint; nested exception is java.lang.IllegalStateException: org.hibernate.TransientPropertyValueException: Not-null property references a transient value - transient instance must be saved beforeQuery current operation : com.test.server.model.workflows.WorkSession.checkPoint -> com.test.server.model.checkpoints.CheckPoint",
    "path": "/api/v1/workSessions/start"
}

我想做的是：

1. 本地化错误和消息字段 (i18n)
2. 可能将消息文本更改为其他内容（始终本地化）

我在 Spring Data REST 文档中没有找到关于如何自定义或本地化异常 (https://docs.spring.io/spring-data/rest/docs/current/reference/html/) 的任何参考。 我希望有一种优雅的方式来做到这一点。

我在我的 WebMvcConfigurerAdapter 中添加了这个：

@Bean
public LocaleResolver localeResolver() {
    return new SmartLocaleResolver();
}

public class SmartLocaleResolver extends CookieLocaleResolver {

    @Override
    public Locale resolveLocale(HttpServletRequest request) {
        String acceptLanguage = request.getHeader("Accept-Language");
        if (acceptLanguage == null || acceptLanguage.trim().isEmpty()) {
            return super.determineDefaultLocale(request);
        }
        return request.getLocale();
    }

}

@Bean
public ResourceBundleMessageSource messageSource() {
    ResourceBundleMessageSource source = new ResourceBundleMessageSource();
    source.setBasenames("i18n/messages"); // name of the resource bundle
    source.setUseCodeAsDefaultMessage(true);
    return source;
}

我想我可以通过这种方式拦截异常：

    @ControllerAdvice(annotations = RepositoryRestController.class)
public class GenericExceptionHandler {

    @ExceptionHandler
    public ResponseEntity handle(Exception e, Locale locale) {
          //missing part...
            return new ResponseEntity(exceptionMessageObject, new HttpHeaders(), httpStatus);
    }

有没有办法使用 Spring 最佳实践将所有内容组合在一起？

Answer 1

@ControllerAdvice(annotations = RepositoryRestController.class)
public class GenericExceptionHandler {
    @Autowired
    private MessageSource messageSource;

    @ExceptionHandler
    //if you don't use Exception e in method you can remove it , live only Locale
    public ResponseEntity handle(Exception e, Locale locale) {

            String errorMessage = messageSource.getMessage(
                                 "error.message", new Object[]{},locale);  
            //set message  or return it instead of exceptionMessageObject
            exceptionMessageObject.setMessage(exceptionMessageObject);

            return new ResponseEntity(exceptionMessageObject, 
                   new HttpHeaders(), httpStatus);
    }

参见春季文档7.15.1 Internationalization using MessageSource

---

" 我应该如何创建 exceptionMessageObject 就像一个 Spring 数据 REST 创建？ "

创建您自己的错误包装器，例如：

public class CustomError {
    private HttpStatus status;
    private String message;
    private Exception originalException;//if you need it        
    // getter setter
}

“如何针对不同的异常有不同的消息？我应该 创建一个长的 if else 链检查异常的类？ "

创建解析器，

private String resolveExceptionToMessage(Exception exceptio){
    //or put in map<Exceptio,String error.message.type1> 
    // String errorCode = map.get(excptio);
    //eturn messageSource.getMessage(errorCode , new Object[]{},locale);
    if(exceptio instanceof ....){
        return messageSource.getMessage("error.message.type1", new Object[]{},locale);
    }
    return "";
}

或者使用 @ExceptionHandler({ CustomException1.class }) , @ExceptionHandler({ CustomException1.class })....的方法，并且在每个方法中只放入 errror.code ，所有其他部分都类似

 @ExceptionHandler({ CustomException1.class})
    public ResponseEntity handleException1() {
        return createError(code for this exceptio 1);
    }
    @ExceptionHandler({ CustomException2.class})
    public ResponseEntity handleException2() {
        return createError(code for this exceptio 2);
    }
    private ResponseEntity createError(String errorCode ) {
            CustomError customError = new CustomError();
            customError.setHttpStatus(HttpStatus.BAD_REQUEST);
            String errorMessage = messageSource.getMessage(
                                 errorCode , new Object[]{},locale); 

            customError.setMessage(errorMessage );
            customError.setOriginalException(e);
            return new ResponseEntity<Object>(customError, new HttpHeaders(), 
                          customError.getStatus());
    }

如何设置httpStatus？我想使用默认状态 Spring Data REST 用于公共异常...

public ResponseEntity handle(Exception e, Locale locale) {
        CustomError customError = new CustomError();
        customError.setHttpStatus(HttpStatus.BAD_REQUEST);
        customError.setMessage(resolveExceptionToMessage(e));
        customError.setOriginalException(e);
        return new ResponseEntity<Object>(customError, new HttpHeaders(), 
                      customError.getStatus());
}

Answer 2

感谢@sbjavateam 的回复。为了完整起见，我想发布另一种方法来做这件事。评论不适合写所有东西，所以我在这里回复。

除了使用@ControllerAdvice，更简单的解决方案是自定义ErrorAttributes：

public class CustomErrorAttributes extends DefaultErrorAttributes {

    private Logger log = LogManager.getLogger();

    @Autowired
    private MessageSource messageSource;

    @Override
    public Map<String, Object> getErrorAttributes(RequestAttributes requestAttributes, boolean includeStackTrace) {
        Locale locale = LocaleContextHolder.getLocale();
        Map<String, Object> errorAttributes = super.getErrorAttributes(requestAttributes, includeStackTrace);
        Throwable throwable = getError(requestAttributes);

        /**
         * Adding the cause if present
         */
        if (throwable != null && throwable.getCause() != null) {
            Throwable cause = throwable.getCause();
            Map<String, Object> causeErrorAttributes = new HashMap<>();
            causeErrorAttributes.put("exception", cause.getClass().getName());
            causeErrorAttributes.put("message", cause.getMessage());
            errorAttributes.put("cause", causeErrorAttributes);
        }

        /**
         * Customizing the message for every exception
         */
        if (throwable instanceof InvalidDataAccessApiUsageException) {
            String message = messageSource.getMessage(throwable.getClass().getName(), new Object[] {}, locale);
            errorAttributes.put("message", message);
        }
        return errorAttributes;
    }
}

当然你必须在你的 WebMvcConfigurerAdapter 中定义这个 bean 或者添加 @Component。在第一种情况下，您需要这样做：

@EnableHypermediaSupport(type = { HypermediaType.HAL })
public class WebMvcConfiguration extends WebMvcConfigurerAdapter {

    @Bean
    public CustomErrorAttributes myCustomErrorAttributes() {
        return new CustomErrorAttributes();
    }

    @Bean
    public MessageSource messageSource() {
        ReloadableResourceBundleMessageSource messageSource = new ReloadableResourceBundleMessageSource();
        messageSource.setBasenames("classpath:/i18n/messages");
        messageSource.setDefaultEncoding("UTF-8");
        messageSource.setUseCodeAsDefaultMessage(true);
        messageSource.setCacheSeconds((int) TimeUnit.HOURS.toSeconds(1));
        messageSource.setFallbackToSystemLocale(false);
        return messageSource;
    }
}

通过这种方式自定义异常非常容易，您可以只覆盖值而不是创建新的自定义异常对象。

Answer 3

在我的项目中，我使用 CustomErrorController。此控制器缓存所有错误，包括 404。 示例：

@Controller
@RequestMapping("${error.path:/error}")
public class CustomErrorController implements ErrorController {

@Value("${error.path:/error}")
private String errorPath;

@Override
public String getErrorPath() {
    return this.errorPath;
}

@RequestMapping
@ResponseBody
public ResponseEntity<Object> error(HttpServletRequest request) {
    HashMap<String, Object> response = new HashMap<String, Object>();
    // your code here...
    return new ResponseEntity<Object>(response, status);
}
}