I am handling exceptions globally in CustomHandler class. I could see while debugging this class is catching exceptions, but not throwing them to client. Please let me know what i am missing...
#ControllerAdvice
public class CustomExceptionHandler extends ResponseEntityExceptionHandler {
#ExceptionHandler(Exception.class)
public final ResponseEntity<Object> handleAllExceptions(Exception ex, WebRequest request) {
List<String> details = new ArrayList<>();
details.add(ex.getLocalizedMessage());
ErrorResponse error = new ErrorResponse("Server Error", details);
return new ResponseEntity<Object>(error, HttpStatus.INTERNAL_SERVER_ERROR);
}
#ExceptionHandler(ConstraintViolationException.class)
public final ResponseEntity<Object> constraintValidationException(
ConstraintViolationException e) {
List<String> details = new ArrayList<>();
for (ConstraintViolation violation : e.getConstraintViolations()) {
details.add(violation.getMessage());
}
ErrorResponse error = new ErrorResponse("Validation Failed", details);
return new ResponseEntity<Object>(error, HttpStatus.BAD_REQUEST);
}
#Override
protected ResponseEntity<Object> handleMethodArgumentNotValid(MethodArgumentNotValidException ex, HttpHeaders headers, HttpStatus status, WebRequest request) {
List<String> details = new ArrayList<>();
for(ObjectError error : ex.getBindingResult().getAllErrors()) {
details.add(error.getDefaultMessage());
}
ErrorResponse error = new ErrorResponse("Validation Failed", details);
return new ResponseEntity(error, HttpStatus.UNPROCESSABLE_ENTITY);
}
Create your own application specific exceptions and handle them. E.g: public class MyAppEx extends RuntimeException {}. Catch the Exception.class and then throw your exception:
try {
// something goes wrong
} catch (Exception e) {
throw new MyAppEx("details of the exception");
}
Replace:
#ExceptionHandler(MyAppEx.class)
public final ResponseEntity<Object> handleAllExceptions(MyAppEx ex, WebRequest request) {..}
I'm using Spring Boot, and I have created a custom PathVariable validator, which I use as follows:
#GetMapping(value = "/test/{id}")
public ResponseEntity<Void> test(#PathVariable("id")
#Valid
#MyGUID(message = "ID_INVALID")
String id) {
return new ResponseEntity<>(HttpStatus.NO_CONTENT);
}
The validor seems to do its job well - it passes when input is valid, and throws exception when not. The problem is, that my custom exception handler doesn't catch the ConstraintViolationException that is thrown. This is the top line of the stack trace:
javax.validation.ConstraintViolationException: ID_INVALID
Then I have my exeception handler class:
#ControllerAdvice
public class RestExceptionController extends ResponseEntityExceptionHandler {
#ExceptionHandler(value = ConstraintViolationException.class)
public ResponseEntity<ErrorResponse> handleConstraintViolationException(ConstraintViolationException ex,
HttpHeaders headers,
HttpStatus status,
WebRequest request) {
List<String> errorDetailsCodes = new ArrayList<>();
for (ConstraintViolation<?> violation : ex.getConstraintViolations()) {
errorDetailsCodes.add(violation.getMessage());
}
ErrorResponse errorResponse = new ErrorResponse(
status.name(),
status.value(),
ex.hashCode(),
errorDetailsCodes
);
logException(ex);
return new ResponseEntity<>(errorResponse, headers, status);
}
#ExceptionHandler(value = Exception.class)
public ResponseEntity<ErrorResponse> handleGeneralException(Exception ex) {
ErrorResponse errorResponse = new ErrorResponse(
HttpStatus.INTERNAL_SERVER_ERROR.name(),
HttpStatus.INTERNAL_SERVER_ERROR.value(),
ex.hashCode()
);
logException(ex);
return new ResponseEntity<>(errorResponse, HttpStatus.INTERNAL_SERVER_ERROR);
}
}
It is strange to me that despite the fact I have both a specific and a general exception handler, they are both skipped, and the system throws its own error:
{
"timestamp": 1568554746642,
"status": 500,
"error": "Internal Server Error",
"message": "ID_INVALID",
"path": "/api/logged-in-user/test/123"
}
How can I catch this exception and return my custom response?
Thanks.
I am trying to implement a custom exception for my Spring boot REST project. The custom exception gets called but shows no impact in the way error message is displayed.
This is the POJO I'm using for my custom errors:
public class ApiError {
private HttpStatus status;
private String message;
private List<String> errors;
public ApiError(HttpStatus status, String message, List<String> errors) {
super();
this.status = status;
this.message = message;
this.errors = errors;
}
public ApiError(HttpStatus status, String message, String error) {
super();
this.status = status;
this.message = message;
errors = Arrays.asList(error);
}
}
This is the exception handler I wrote:
#ControllerAdvice
#EnableWebMvc
public class ApiExceptionHandler extends ResponseEntityExceptionHandler {
#ExceptionHandler(Exception.class)
public final ResponseEntity<Object> handleAllExceptions(Exception ex, WebRequest request) {
System.out.println("Custom exception!!");
//List<String> details = new ArrayList<>();
//details.add(ex.getLocalizedMessage());
//System.out.println("Localize message:: "+ex.getLocalizedMessage());
// ExceptionResponse exceptionResponse = new ExceptionResponse(new Date(), ex.getMessage(),
//request.getDescription(false));
ApiError error = new ApiError(HttpStatus.INTERNAL_SERVER_ERROR,"Server Error", request.getDescription(false));
return new ResponseEntity<Object>(error, HttpStatus.INTERNAL_SERVER_ERROR);
}
}
Additionally, I'm defined the following method within my controller:
#RequestMapping(value = "/model", params = "number", method = RequestMethod.GET, produces = "application/json")
List<Model> getModel(HttpServletRequest request,#RequestParam(value = "codeNumber") String number) throws Exception{
List<Model> model = null;
try {
model = niiService.getModel(number);
}catch(RuntimeException e){
new Exception(e);
}
return model;
}
However, in stead of my custom POJO, I'm seeing the following exception:
{
"timestamp": 1547013989124,
"status": 500,
"error": "Internal Server Error",
"message": "Request processing failed; nested exception is org.springframework.transaction.CannotCreateTransactionException: Could not open JDBC Connection for transaction; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure\n\nThe last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.",
"path": "/model"
}
I was expecting the following JSON structure in stead:
{
"status": 500,
"message": "Server Error"
..
}
Please let me know, what I am missing to get the error response in the way I wanted.
You are missing the throw in front of the custom exception.
Also make sure that you are catching the right exception inside your controller.
Change
catch (RuntimeException e) {
//custom exception
new Exception(e);
}
To
catch (RuntimeException e) {
//custom exception
throw new Exception(e);
}
I missed adding getter and setter to APIError class. Hence, the response was not coming in the way I expected.
Below is the code snippet; basically, I am trying to propagate the exception when the error code is anything other than 200.
ResponseEntity<Object> response = restTemplate.exchange(url.toString().replace("{version}", version),
HttpMethod.POST, entity, Object.class);
if(response.getStatusCode().value()!= 200){
logger.debug("Encountered Error while Calling API");
throw new ApplicationException();
}
However in the case of a 500 response from the server I am getting the exception
org.springframework.web.client.HttpServerErrorException: 500 Internal Server Error
at org.springframework.web.client.DefaultResponseErrorHandler.handleError(DefaultResponseErrorHandler.java:94) ~[spring-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
Do I really need to wrap the rest template exchange method in try? What would then be the purpose of codes?
You want to create a class that implements ResponseErrorHandler and then use an instance of it to set the error handling of your rest template:
public class MyErrorHandler implements ResponseErrorHandler {
#Override
public void handleError(ClientHttpResponse response) throws IOException {
// your error handling here
}
#Override
public boolean hasError(ClientHttpResponse response) throws IOException {
...
}
}
[...]
public static void main(String args[]) {
RestTemplate restTemplate = new RestTemplate();
restTemplate.setErrorHandler(new MyErrorHandler());
}
Also, Spring has the class DefaultResponseErrorHandler, which you can extend instead of implementing the interface, in case you only want to override the handleError method.
public class MyErrorHandler extends DefaultResponseErrorHandler {
#Override
public void handleError(ClientHttpResponse response) throws IOException {
// your error handling here
}
}
Take a look at its source code to have an idea of how Spring handles HTTP errors.
Spring cleverly treats http error codes as exceptions, and assumes that your exception handling code has the context to handle the error. To get exchange to function as you would expect it, do this:
try {
return restTemplate.exchange(url, httpMethod, httpEntity, String.class);
} catch(HttpStatusCodeException e) {
return ResponseEntity.status(e.getRawStatusCode()).headers(e.getResponseHeaders())
.body(e.getResponseBodyAsString());
}
This will return all the expected results from the response.
You should catch a HttpStatusCodeException exception:
try {
restTemplate.exchange(...);
} catch (HttpStatusCodeException exception) {
int statusCode = exception.getStatusCode().value();
...
}
Another solution is the one described here at the end of this post by "enlian":
http://springinpractice.com/2013/10/07/handling-json-error-object-responses-with-springs-resttemplate
try{
restTemplate.exchange(...)
} catch(HttpStatusCodeException e){
String errorpayload = e.getResponseBodyAsString();
//do whatever you want
} catch(RestClientException e){
//no response payload, tell the user sth else
}
Spring abstracts you from the very very very large list of http status code. That is the idea of the exceptions. Take a look into org.springframework.web.client.RestClientException hierarchy:
You have a bunch of classes to map the most common situations when dealing with http responses. The http codes list is really large, you won't want write code to handle each situation. But for example, take a look into the HttpClientErrorException sub-hierarchy. You have a single exception to map any 4xx kind of error. If you need to go deep, then you can. But with just catching HttpClientErrorException, you can handle any situation where bad data was provided to the service.
The DefaultResponseErrorHandler is really simple and solid. If the response status code is not from the family of 2xx, it just returns true for the hasError method.
I have handled this as below:
try {
response = restTemplate.postForEntity(requestUrl, new HttpEntity<>(requestBody, headers), String.class);
} catch (HttpStatusCodeException ex) {
response = new ResponseEntity<String>(ex.getResponseBodyAsString(), ex.getResponseHeaders(), ex.getStatusCode());
}
A very simple solution can be:
try {
requestEntity = RequestEntity
.get(new URI("user String"));
return restTemplate.exchange(requestEntity, String.class);
} catch (RestClientResponseException e) {
return ResponseEntity.status(e.getRawStatusCode()).body(e.getResponseBodyAsString());
}
If you use pooling (http client factory) or load balancing (eureka) mechanism with your RestTemplate, you will not have the luxury of creating a new RestTemplate per class. If you are calling more than one service you cannot use setErrorHandler because if would be globally used for all your requests.
In this case, catching the HttpStatusCodeException seems to be the better option.
The only other option you have is to define multiple RestTemplate instances using the #Qualifier annotation.
Also - but this is my own taste - I like my error handling snuggled tightly to my calls.
The code of exchange is below:
public <T> ResponseEntity<T> exchange(String url, HttpMethod method,
HttpEntity<?> requestEntity, Class<T> responseType, Object... uriVariables) throws RestClientException
Exception RestClientException has HttpClientErrorException and HttpStatusCodeException exception.
So in RestTemplete there may occure HttpClientErrorException and HttpStatusCodeException exception.
In exception object you can get exact error message using this way: exception.getResponseBodyAsString()
Here is the example code:
public Object callToRestService(HttpMethod httpMethod, String url, Object requestObject, Class<?> responseObject) {
printLog( "Url : " + url);
printLog( "callToRestService Request : " + new GsonBuilder().setPrettyPrinting().create().toJson(requestObject));
try {
RestTemplate restTemplate = new RestTemplate();
restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
restTemplate.getMessageConverters().add(new StringHttpMessageConverter());
HttpHeaders requestHeaders = new HttpHeaders();
requestHeaders.setContentType(MediaType.APPLICATION_JSON);
HttpEntity<Object> entity = new HttpEntity<>(requestObject, requestHeaders);
long start = System.currentTimeMillis();
ResponseEntity<?> responseEntity = restTemplate.exchange(url, httpMethod, entity, responseObject);
printLog( "callToRestService Status : " + responseEntity.getStatusCodeValue());
printLog( "callToRestService Body : " + new GsonBuilder().setPrettyPrinting().create().toJson(responseEntity.getBody()));
long elapsedTime = System.currentTimeMillis() - start;
printLog( "callToRestService Execution time: " + elapsedTime + " Milliseconds)");
if (responseEntity.getStatusCodeValue() == 200 && responseEntity.getBody() != null) {
return responseEntity.getBody();
}
} catch (HttpClientErrorException exception) {
printLog( "callToRestService Error :" + exception.getResponseBodyAsString());
//Handle exception here
}catch (HttpStatusCodeException exception) {
printLog( "callToRestService Error :" + exception.getResponseBodyAsString());
//Handle exception here
}
return null;
}
Here is the code description:
In this method you have to pass request and response class. This method will automatically parse response as requested object.
First of All you have to add message converter.
restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
restTemplate.getMessageConverters().add(new StringHttpMessageConverter());
Then you have to add requestHeader.
Here is the code:
HttpHeaders requestHeaders = new HttpHeaders();
requestHeaders.setContentType(MediaType.APPLICATION_JSON);
HttpEntity<Object> entity = new HttpEntity<>(requestObject, requestHeaders);
Finally, you have to call exchange method:
ResponseEntity<?> responseEntity = restTemplate.exchange(url, httpMethod, entity, responseObject);
For prety printing i used Gson library.
here is the gradle : compile 'com.google.code.gson:gson:2.4'
You can just call the bellow code to get response:
ResponseObject response=new RestExample().callToRestService(HttpMethod.POST,"URL_HERE",new RequestObject(),ResponseObject.class);
Here is the full working code:
import com.google.gson.GsonBuilder;
import org.springframework.http.*;
import org.springframework.http.converter.StringHttpMessageConverter;
import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
import org.springframework.web.client.HttpClientErrorException;
import org.springframework.web.client.HttpStatusCodeException;
import org.springframework.web.client.RestTemplate;
public class RestExample {
public RestExample() {
}
public Object callToRestService(HttpMethod httpMethod, String url, Object requestObject, Class<?> responseObject) {
printLog( "Url : " + url);
printLog( "callToRestService Request : " + new GsonBuilder().setPrettyPrinting().create().toJson(requestObject));
try {
RestTemplate restTemplate = new RestTemplate();
restTemplate.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
restTemplate.getMessageConverters().add(new StringHttpMessageConverter());
HttpHeaders requestHeaders = new HttpHeaders();
requestHeaders.setContentType(MediaType.APPLICATION_JSON);
HttpEntity<Object> entity = new HttpEntity<>(requestObject, requestHeaders);
long start = System.currentTimeMillis();
ResponseEntity<?> responseEntity = restTemplate.exchange(url, httpMethod, entity, responseObject);
printLog( "callToRestService Status : " + responseEntity.getStatusCodeValue());
printLog( "callToRestService Body : " + new GsonBuilder().setPrettyPrinting().create().toJson(responseEntity.getBody()));
long elapsedTime = System.currentTimeMillis() - start;
printLog( "callToRestService Execution time: " + elapsedTime + " Milliseconds)");
if (responseEntity.getStatusCodeValue() == 200 && responseEntity.getBody() != null) {
return responseEntity.getBody();
}
} catch (HttpClientErrorException exception) {
printLog( "callToRestService Error :" + exception.getResponseBodyAsString());
//Handle exception here
}catch (HttpStatusCodeException exception) {
printLog( "callToRestService Error :" + exception.getResponseBodyAsString());
//Handle exception here
}
return null;
}
private void printLog(String message){
System.out.println(message);
}
}
Thanks :)
To extedend #carcaret answer a bit....
Consider your response errors are returned by json message. For example the API may return 204 as status code error and a json message as error list. In this case you need to define which messages should spring consider as error and how to consume them.
As a sample your API may return some thing like this, if error happens:
{ "errorCode":"TSC100" , "errorMessage":"The foo bar error happend" , "requestTime" : "202112827733" .... }
To consume above json and throw a custom exception, you can do as below:
First define a class for mapping error ro object
//just to map the json to object
public class ServiceErrorResponse implements Serializable {
//setter and getters
private Object errorMessage;
private String errorCode;
private String requestTime;
}
Now define the error handler:
public class ServiceResponseErrorHandler implements ResponseErrorHandler {
private List<HttpMessageConverter<?>> messageConverters;
#Override
public boolean hasError(ClientHttpResponse response) throws IOException {
return (response.getStatusCode().is4xxClientError() ||
response.getStatusCode().is5xxServerError());
}
#Override
public void handleError(ClientHttpResponse response) throws IOException {
#SuppressWarnings({ "unchecked", "rawtypes" })
HttpMessageConverterExtractor<ServiceErrorResponse> errorMessageExtractor =
new HttpMessageConverterExtractor(ServiceErrorResponse.class, messageConverters);
ServiceErrorResponse errorObject = errorMessageExtractor.extractData(response);
throw new ResponseEntityErrorException(
ResponseEntity.status(response.getRawStatusCode())
.headers(response.getHeaders())
.body(errorObject)
);
}
public void setMessageConverters(List<HttpMessageConverter<?>> messageConverters) {
this.messageConverters = messageConverters;
}
}
The custom Exception will be:
public class ResponseEntityErrorException extends RuntimeException {
private ResponseEntity<ServiceErrorResponse> serviceErrorResponseResponse;
public ResponseEntityErrorException(ResponseEntity<ServiceErrorResponse> serviceErrorResponseResponse) {
this.serviceErrorResponseResponse = serviceErrorResponseResponse;
}
public ResponseEntity<ServiceErrorResponse> getServiceErrorResponseResponse() {
return serviceErrorResponseResponse;
}
}
To use it:
RestTemplateResponseErrorHandler errorHandler = new
RestTemplateResponseErrorHandler();
//pass the messageConverters to errror handler and let it convert json to object
errorHandler.setMessageConverters(restTemplate.getMessageConverters());
restTemplate.setErrorHandler(errorHandler);
This is how to handle exceptions in Rest Template
try {
return restTemplate.exchange("URL", HttpMethod.POST, entity, String.class);
}
catch (HttpStatusCodeException e)
{
return ResponseEntity.status(e.getRawStatusCode()).headers(e.getResponseHeaders())
.body(e.getResponseBodyAsString());
}
Here is my POST method with HTTPS which returns a response body for any type of bad responses.
public String postHTTPSRequest(String url,String requestJson)
{
//SSL Context
CloseableHttpClient httpClient = HttpClients.custom().setSSLHostnameVerifier(new NoopHostnameVerifier()).build();
HttpComponentsClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory();
requestFactory.setHttpClient(httpClient);
//Initiate REST Template
RestTemplate restTemplate = new RestTemplate(requestFactory);
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
//Send the Request and get the response.
HttpEntity<String> entity = new HttpEntity<String>(requestJson,headers);
ResponseEntity<String> response;
String stringResponse = "";
try {
response = restTemplate.postForEntity(url, entity, String.class);
stringResponse = response.getBody();
}
catch (HttpClientErrorException e)
{
stringResponse = e.getResponseBodyAsString();
}
return stringResponse;
}
I fixed it by overriding the hasError method from DefaultResponseErrorHandler class:
public class BadRequestSafeRestTemplateErrorHandler extends DefaultResponseErrorHandler
{
#Override
protected boolean hasError(HttpStatus statusCode)
{
if(statusCode == HttpStatus.BAD_REQUEST)
{
return false;
}
return statusCode.isError();
}
}
And you need to set this handler for restemplate bean:
#Bean
protected RestTemplate restTemplate(RestTemplateBuilder builder)
{
return builder.errorHandler(new BadRequestSafeRestTemplateErrorHandler()).build();
}
Read about global exception handling in global exception handler add the below method. this will work.
#ExceptionHandler( {HttpClientErrorException.class, HttpStatusCodeException.class, HttpServerErrorException.class})
#ResponseBody
public ResponseEntity<Object> httpClientErrorException(HttpStatusCodeException e) throws IOException {
BodyBuilder bodyBuilder = ResponseEntity.status(e.getRawStatusCode()).header("X-Backend-Status", String.valueOf(e.getRawStatusCode()));
if (e.getResponseHeaders().getContentType() != null) {
bodyBuilder.contentType(e.getResponseHeaders().getContentType());
}
return bodyBuilder.body(e.getResponseBodyAsString());
}
There is also an option to use TestRestTemplate. It is very useful for integration and E2E tests, when you need to validate all status codes manually (for example in negative test-cases).
TestRestTemplate is fault-tolerant. This means that 4xx and 5xx do not result in an exception being thrown and can instead be detected via the response entity and its status code.
Try using #ControllerAdvice. This allows you to handle the exception only once and have all 'custom' handled exceptions in one place.
https://docs.spring.io/spring-framework/docs/current/javadoc-api/org/springframework/web/bind/annotation/ControllerAdvice.html
example
#ControllerAdvice
public class MyExceptionHandler extends ResponseEntityExceptionHandler{
#ExceptionHandler(MyException.class)
protected ResponseEntity<Object> handleMyException(){
MyException exception,
WebRequest webRequest) {
return handleExceptionInternal(
exception,
exception.getMessage(),
exception.getResponseHeaders(),
exception.getStatusCode(),
webRequest);
}
I have the the following controller with one RequestMapping which produces an xml MediaType.
#RestController
#RequestMapping("/api")
public class ArticleResource {
#RequestMapping(value = "/xml/{id}", method = RequestMethod.GET, produces = MediaType.APPLICATION_XML_VALUE)
public ResponseEntity<byte[]> getXml(#PathVariable(value = "id") String id,
final HttpServletRequest request,
final HttpServletResponse response) {
InputStream inputStream = null;
try {
inputStream = new FileInputStream(path + id + ".xml");
} catch (FileNotFoundException e) {
throw new BadRequestException("No such xml exists");
}
try {
return new ResponseEntity<byte[]>(IOUtils.toByteArray(inputStream), HttpStatus.OK);
} catch (IOException e) {
e.printStackTrace();
}
return new ResponseEntity<byte[]>(HttpStatus.NOT_FOUND);
}
}
The BadRequestException implementation is the following:
#ResponseStatus(value = HttpStatus.BAD_REQUEST)
public class BadRequestException extends RuntimeException {
public BadRequestException(String message) {
super(message);
}
}
It works fine when the xml exists, but when the xml cannot be found I have a 406 error code. I suppose the problem occurs because it expects a xml media type and instead a RuntimeException is returned. How can I tackle with this issue?
Do you have an Accept: header in your HTTP request? Your error handler will just return an HTTP error code (response status) so it causes a 406 Not Acceptable on the client side if the client expects XML.
If this is the case you can return an XML response entity from the error handler and update your signature to reflect that it produces XML. Or you can try removing the Accepts from your request.
I solved my issue by returning the following:
String returnString = "XML file don't exists";
return new ResponseEntity<byte[]>(IOUtils.toByteArray(
new ByteArrayInputStream(returnString.getBytes())), HttpStatus.NOT_FOUND);