抛出异常时，Spring Boot 不显示自定义错误

Question

我对 Java/Spring 领域相当陌生，我正在尝试在我的 Spring Boot 应用程序中使用 @ControllerAdvice。 ControllerAdvice 捕获异常但不显示我的自定义响应。

以下是引发异常的RestController的快照

ResponseEntity<MyClass> response = new ResponseEntity<MyClass>(HttpStatus.OK);

    try {   
        response = restTemplate.exchange(url, HttpMethod.GET, entity, MyClass.class);
    } catch (HttpClientErrorException  ex) {        
        throw ex;
    }catch (HttpServerErrorException   ex) {
        logger.debug(ex.getMessage() + " Server Status Code - " + ex.getStatusCode());
    }
    catch(Exception ex) {
        logger.debug(ex.getMessage() + " Generic Exception ");
    }

以下是 @ControllerAdvice

@ControllerAdvice
public class GlobalExceptionHandler extends Exception {

    @ExceptionHandler(HttpClientErrorException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public ErrorResponse errorHandle(HttpClientErrorException ex) {

          String responseBody = ex.getResponseBodyAsString(); 

          ObjectMapper mapper = new ObjectMapper();
          mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
          ErrorResponse errorResponse = new ErrorResponse();
          try { 
              errorResponse = mapper.readValue(responseBody, ErrorResponse.class); 

          } catch (JsonMappingException e) { 
          e.printStackTrace(); 
          } catch (JsonProcessingException e) { 
              e.printStackTrace(); 
          }
        return errorResponse;
    }
}

和其他类

@JsonIgnoreProperties
public class ErrorResponse {
    @JsonProperty("error")
    public Error error;

      @JsonProperty("version") 
      public String version;

}

public class Error {
    @JsonProperty("code")
    public String Code;

    @JsonProperty("message")
    public String Message;

    public String getCode() {
        return Code;
    }

    public void setCode(String code) {
        Code = code;
    }

    public String getMessage() {
        return Message;
    }

    public void setMessage(String message) {
        Message = message;
    }

}

我在使用 POSTMAN 时遇到的错误是

{
    "timestamp": "2019-11-20T05:42:24.126+0000",
    "status": 404,
    "error": "Not Found",
    "message": "400 Bad Request",
    "path": "myApi/somecontroller"
}

我在浏览器上遇到的错误如下

Whitelabel Error Page
This application has no explicit mapping for /error, so you are seeing this as a fallback.

Tue Nov 19 23:40:26 CST 2019
There was an unexpected error (type=Not Found, status=404).
400 Bad Request

任何想法/建议为什么会出现这种行为？我期待 ErrorResponse 类的 JSON 表示。

更新

Answer 1

这不是异常，这是错误场景

尝试使用以下代码。

@RestController
public class IndexController implements ErrorController{

    private static final String PATH = "/error";

    @RequestMapping(value = PATH)
    public String error() {
        return "Error handling";
    }

    @Override
    public String getErrorPath() {
        return PATH;
    }
}

需要重写的Spring Boot默认寄存器BasicErrorController

Answer 2

在您的情况下，您有一个控制器建议方法，该方法返回特定异常的 Json 响应。因此，检查浏览器 ui 中的响应是没有意义的，因为您需要通过另一个异常处理程序配置适当的错误页面才能按您的意愿工作。否则会显示默认的spring白标错误页面。

对于其余的异常处理程序，我认为当您使用对象映射器创建实例时，JSON 结构没有得到正确转换。试试吧：

@ControllerAdvice
public class GlobalExceptionHandler extends Exception {

    @ExceptionHandler(HttpClientErrorException.class)
    @ResponseStatus(HttpStatus.BAD_REQUEST)
    public ErrorResponse errorHandle(HttpClientErrorException ex) {

          String responseBody = ex.getResponseBodyAsString(); // The response body structure is different, you should get the message and stacktrace separately and assign it to your own response object
          ErrorResponse errorResponse = new ErrorResponse();
          Error error = new Error();
          error.setMessage(ex.getMessage());
          error.setCode(HttpStatus.BAD_REQUEST);
          errorResponse.setError(error);
          return errorResponse;
    }
}

getResponseBodyAsString - 返回转换为的响应正文 细绳。使用的字符集是响应“Content-Type”或 否则为“UTF-8”。

Answer 3

在进行了一些测试/搜索后，发现了这一点。使用下面的Controller就能做到这一点

@ControllerAdvice
public class GlobalExceptionHandler extends Exception {

    @ExceptionHandler(value = { HttpClientErrorException.class })
    public ResponseEntity<Object> handleResourceNotFoundException(HttpClientErrorException ex) {
        String responseBody = ex.getResponseBodyAsString();
        HttpHeaders headers = new HttpHeaders();

        headers.setContentType(MediaType.APPLICATION_JSON);     
        ObjectMapper mapper = new ObjectMapper();
        mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
        ErrorResponse errorResponse = new ErrorResponse(); 
        try { 
            errorResponse = mapper.readValue(responseBody, ErrorResponse.class);         
        } catch (JsonMappingException e) { 
            e.printStackTrace(); 
            } 
        catch (JsonProcessingException e) { 
                e.printStackTrace(); 
            }

        ResponseEntity<Object> response = new ResponseEntity<>(errorResponse, headers, HttpStatus.BAD_REQUEST);

        return response;
    }
}