使用Spring Data REST处理自定义异常（i18n）
问题内容：
我正在将Spring Boot 1.5.4与Spring JPA，Spring Data
REST，HATEOAS结合使用…我正在寻找最佳实践（Spring方式）来自定义Spring Data REST正在管理添加i18n支持的异常。
我查看了MessageException类（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
）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：
- 本地化错误和消息字段（i18n）
- 可能将消息文本更改为其他内容（始终本地化）
我没有在Spring Data REST文档中找到任何有关如何自定义或本地化异常的参考（https://docs.spring.io/spring-
data/rest/docs/current/reference/html/）。我希望有一种优雅的方法可以做到这一点。
我在WebMvcConfigurerAdapter中添加了以下内容：
@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放在一起？
问题答案：
@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Spring
7.15.1使用MessageSource进行国际化
“我应该如何像创建一个Spring Data REST一样创建exceptionMessageObject？”
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
}
“如何为不同的异常提供不同的消息？我是否应该创建一条长的if链来检查异常的类？”
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 "";
}
或将方法与@ExceptionHandler（{CustomException1.class}），@ExceptionHandler（{CustomException1.class}）....一起使用，并在每个方法中仅添加errror.code，其他所有部分都相似
@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？我想将默认状态Spring Data REST用于常见异常…
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());
}
