I have created one filter in zuul service.
I am able to get the response status but I am not able to get the response contenttype.
Code:
public class UserEventFilter extends ZuulFilter {
#Override
public Object run() {
RequestContext ctx = RequestContext.getCurrentContext();
HttpServletRequest request = ctx.getRequest();
HttpServletResponse response = ctx.getResponse();
System.out.println("response status:" + response.getStatus());
System.out.println("response status:" + ctx.getResponseStatusCode());
System.out.println("response content type:" + response.getContentType());
try (final InputStream responseDataStream = ctx.getResponseDataStream()) {
final String responseData = CharStreams
.toString(new InputStreamReader(responseDataStream, Constants.ENCODING_UTF_8));
ctx.setResponseBody(responseData);
System.out.println("responseData:"+responseData);
} catch (IOException exception) {
exception.printStackTrace();
}
}
}
response content type is giving null.
What I want to do is, I have to get the response body for all responses except if it is "application/octet-stream".
Try this:
RequestContext context = RequestContext.getCurrentContext();
List<Pair<String, String>> headers = context.getZuulResponseHeaders();
Than find content type there. You should override filterType method:
#Override
public String filterType() {
return POST_TYPE;
}
that is POST filter, if you want response I guess you are using post filter.
I need to upload a photo to the server which has been written using Spring Boot. For the front end which sends the request I use Angular2.
This is my API which accepts the HTTP request. It works fine. (I tested it using Postman)
#RequestMapping(method = RequestMethod.POST, value = "/tender/save-new/save-photo")
public ResponseEntity<?> uploadPhoto(#RequestParam("file") MultipartFile file){
if (file.isEmpty()) {
ErrorResponse errorResponse = new ErrorResponse();
errorResponse.setMessage("DEBUG: Attached file is empty");
return new ResponseEntity<ErrorResponse>(errorResponse, HttpStatus.NOT_FOUND);
}
String returnPath = null;
try {
// upload stuff
} catch (IOException e) {
ErrorResponse errorResponse = new ErrorResponse();
errorResponse.setMessage(e.getMessage());
return new ResponseEntity<ErrorResponse> (errorResponse, HttpStatus.INTERNAL_SERVER_ERROR);
}
return new ResponseEntity<String>(returnPath, HttpStatus.OK);
}
I am not sure how should I write the code in Angular2 to call the server.
Following is what I have come up with.
savePhoto(photoToSave: File) {
let formData: FormData = new FormData();
formData.append('file', photoToSave);
let savedPath = this._http
.post(this._endpointUrl + "tender/save-new/save-photo", formData)
.map(
res => {
return res.json();
}
)
.catch(handleError);
return savedPath;
}
As you can see, I append the 'file' parameter to the form data before sending it. Server method accepts the RequestParam as 'file'.
But, in the server log, I get following error.
org.springframework.web.multipart.MultipartException: Current request
is not a multipart request at
org.springframework.web.method.annotation.RequestParamMethodArgumentResolver.handleMissingValue(RequestParamMethodArgumentResolver.java:190)
Note that I haven't declared a CommonsMultipartResolver bean since SprinBoot implicitly handles it. (I have heard this. Please correct if I am wrong.)
I think that the error comes up because of a missing value in the request. What Spring is saying by handleMissingValue? What am I missing?
you need to specify that your controller is expecting multipart
#RequestMapping(method = RequestMethod.POST, value = "/tender/save-new/save-photo", consumes = {"multipart/form-data"})
public ResponseEntity<?> uploadPhoto(#RequestParam("file") MultipartFile file){
Also to solve the CORS problem you need to add the methods you are planning to use in your cors mapping, try something like this
#Configuration
public class WebMvcConfiguration {
#Bean
public WebMvcConfigurer corsConfigurer() {
return new WebMvcConfigurerAdapter() {
#Override
public void addCorsMappings(CorsRegistry registry) {
registry.addMapping("/**").allowedMethods("GET", "POST", "PUT", "DELETE", "HEAD");
}
};
}
}
i had the same problem, this is the solution i am using right now:
for the back end using spring boot:
#RequestMapping(value="/save", method = RequestMethod.POST)
public ResponseEntity<?> saveTemp(#RequestParam("file") MultipartFile file) throws Exception{
String nomFichier=file.getOriginalFilename();
try {
byte[] bytes = file.getBytes();
File fi=new File(tempRepo+nomFichier);
fi.getParentFile().mkdirs();
BufferedOutputStream bufferedOutputStream = new BufferedOutputStream((new FileOutputStream(fi)));
bufferedOutputStream.write(bytes);
bufferedOutputStream.close();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return new ResponseEntity<>(HttpStatus.BAD_REQUEST);
}
return new ResponseEntity<>(HttpStatus.OK);
}
for the front end using Angular2:
public save(file:any){
const formData = new FormData();
formData.append("file", file);
return this._http
.post('http://localhost:8081/save', formData)
.catch(this._errorhandler);
}
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 am calling a ReST service through RestTemplate and trying to override ResponseErrorHandler in Spring 3.2 to handle custom error codes.
CustomResponseErrroHandler
public class MyResponseErrorHandler implements ResponseErrorHandler {
#Override
public boolean hasError(ClientHttpResponse response) throws IOException {
boolean hasError = false;
int rawStatusCode = response.getRawStatusCode();
if (rawStatusCode != 200){
hasError = true;
}
return hasError;
}
#Override
public void handleError(ClientHttpResponse response) throws IOException {
//String body = IOUtils.toString(response.getBody());
throw new CustomServiceException(response.getRawStatusCode() , "custom Error");
}
}
Spring framework invokes hasError method but not handleError, so I couldn't throw my custom exception. After delving into Spring RestTemplate source code, I realized that the code in handleResponseError method is causing the issue - It is looking for response.getStatusCode or response.getStatusText and throwing exception (as statusCode/statusText is null when Rest service throws exception) and it never calls either custom implemented or default handleError method in the next line.
Spring RestTemplate source code for handleResponse method:
private void handleResponseError(HttpMethod method, URI url, ClientHttpResponse response) throws IOException {
if (logger.isWarnEnabled()) {
try {
logger.warn(method.name() + " request for \"" + url + "\" resulted in " +
response.getStatusCode() + " (" + response.getStatusText() + "); invoking error handler");
}
catch (IOException e) {
// ignore
}
}
getErrorHandler().handleError(response);
}
FYI, while service throws exception, I can read rawstatuscode but not statuscode from response
How to bypass this framework code and make call my custom handler?
Thanks for your help in advance.
Following link has useful information about Exception Flow for Spring ResponseErrorHandler .
Adding code here, just in-case the blog is down:
Code for ErrorHandler:
public class MyResponseErrorHandler implements ResponseErrorHandler {
private static final Log logger = LogFactory.getLog(MyResponseErrorHandler.class);
#Override
public void handleError(ClientHttpResponse clienthttpresponse) throws IOException {
if (clienthttpresponse.getStatusCode() == HttpStatus.FORBIDDEN) {
logger.debug(HttpStatus.FORBIDDEN + " response. Throwing authentication exception");
throw new AuthenticationException();
}
}
#Override
public boolean hasError(ClientHttpResponse clienthttpresponse) throws IOException {
if (clienthttpresponse.getStatusCode() != HttpStatus.OK) {
logger.debug("Status code: " + clienthttpresponse.getStatusCode());
logger.debug("Response" + clienthttpresponse.getStatusText());
logger.debug(clienthttpresponse.getBody());
if (clienthttpresponse.getStatusCode() == HttpStatus.FORBIDDEN) {
logger.debug("Call returned a error 403 forbidden resposne ");
return true;
}
}
return false;
}
}
Code for using it in RestTemplate:
RestTemplate restclient = new RestTemplate();
restclient.setErrorHandler(new MyResponseErrorHandler());
ResponseEntity<String> responseEntity = clientRestTemplate.exchange(
URI,
HttpMethod.GET,
requestEntity,
String.class);
response = responseEntity.getBody();
I don't see your RestTemplate code, but I assume you to set your ResponseErrorHandler for RestTemplate to use like:
RestTemplate restClient = new RestTemplate();
restClient.setErrorHandler(new MyResponseErrorHandler());
The exception is indeed thrown in handleError method. You can find how to throw CustomException using CustomResponseHandler from one of my previous answers.
I have a rest service which send an 404 error when the resources is not found.
Here the source of my controller and the exception which send Http 404.
#Controller
#RequestMapping("/site")
public class SiteController
{
#Autowired
private IStoreManager storeManager;
#RequestMapping(value = "/stores/{pkStore}", method = RequestMethod.GET, produces = "application/json")
#ResponseBody
public StoreDto getStoreByPk(#PathVariable long pkStore) {
Store s = storeManager.getStore(pkStore);
if (null == s) {
throw new ResourceNotFoundException("no store with pkStore : " + pkStore);
}
return StoreDto.entityToDto(s);
}
}
#ResponseStatus(value = HttpStatus.NOT_FOUND)
public class ResourceNotFoundException extends RuntimeException
{
private static final long serialVersionUID = -6252766749487342137L;
public ResourceNotFoundException(String message) {
super(message);
}
}
When i try to call it with RestTemplate with this code :
ResponseEntity<StoreDto> r = restTemplate.getForEntity(url, StoreDto.class, m);
System.out.println(r.getStatusCode());
System.out.println(r.getBody());
I receive this exception :
org.springframework.web.client.RestTemplate handleResponseError
ATTENTION: GET request for "http://........./stores/99" resulted in 404 (Introuvable); invoking error handler
org.springframework.web.client.HttpClientErrorException: 404 Introuvable
I was thinking I can explore my responseEntity Object and do some things with the statusCode. But exception is launch and my app go down.
Is there a specific configuration for restTemplate to not send exception but populate my ResponseEntity.
As far as I'm aware, you can't get an actual ResponseEntity, but the status code and body (if any) can be obtained from the exception:
try {
ResponseEntity<StoreDto> r = restTemplate.getForEntity(url, StoreDto.class, m);
}
catch (final HttpClientErrorException e) {
System.out.println(e.getStatusCode());
System.out.println(e.getResponseBodyAsString());
}
RESTTemplate is quite deficient in this area IMO. There's a good blog post here about how you could possibly extract the response body when you've received an error:
http://springinpractice.com/2013/10/07/handling-json-error-object-responses-with-springs-resttemplate
As of today there is an outstanding JIRA request that the template provides the possibility to extract the response body:
https://jira.spring.io/browse/SPR-10961
The trouble with Squatting Bear's answer is that you would have to interrogate the status code inside the catch block eg if you're only wanting to deal with 404's
Here's how I got around this on my last project. There may be better ways, and my solution doesn't extract the ResponseBody at all.
public class ClientErrorHandler implements ResponseErrorHandler
{
#Override
public void handleError(ClientHttpResponse response) throws IOException
{
if (response.getStatusCode() == HttpStatus.NOT_FOUND)
{
throw new ResourceNotFoundException();
}
// handle other possibilities, then use the catch all...
throw new UnexpectedHttpException(response.getStatusCode());
}
#Override
public boolean hasError(ClientHttpResponse response) throws IOException
{
return response.getStatusCode().series() == HttpStatus.Series.CLIENT_ERROR
|| response.getStatusCode().series() == HttpStatus.Series.SERVER_ERROR;
}
The ResourceNotFoundException and UnexpectedHttpException are my own unchecked exceptions.
The when creating the rest template:
RestTemplate template = new RestTemplate();
template.setErrorHandler(new ClientErrorHandler());
Now we get the slightly neater construct when making a request:
try
{
HttpEntity response = template.exchange("http://localhost:8080/mywebapp/customer/100029",
HttpMethod.GET, requestEntity, String.class);
System.out.println(response.getBody());
}
catch (ResourceNotFoundException e)
{
System.out.println("Customer not found");
}
Since it's 2018 and I hope that when people say "Spring" they actually mean "Spring Boot" at least, I wanted to expand the given answers with a less dust-covered approach.
Everything mentioned in the previous answers is correct - you need to use a custom ResponseErrorHandler.
Now, in Spring Boot world the way to configure it is a bit simpler than before.
There is a convenient class called RestTemplateBuilder. If you read the very first line of its java doc it says:
Builder that can be used to configure and create a RestTemplate.
Provides convenience methods to register converters, error handlers
and UriTemplateHandlers.
It actually has a method just for that:
new RestTemplateBuilder().errorHandler(new DefaultResponseErrorHandler()).build();
On top of that, Spring guys realized the drawbacks of a conventional RestTemplate long time ago, and how it can be especially painful in tests. They created a convenient class, TestRestTemplate, which serves as a wrapper around RestTemplate and set its errorHandler to an empty implementation:
private static class NoOpResponseErrorHandler extends
DefaultResponseErrorHandler {
#Override
public void handleError(ClientHttpResponse response) throws IOException {
}
}
You can create your own RestTemplate wrapper which does not throw exceptions, but returns a response with the received status code. (You could also return the body, but that would stop being type-safe, so in the code below the body remains simply null.)
/**
* A Rest Template that doesn't throw exceptions if a method returns something other than 2xx
*/
public class GracefulRestTemplate extends RestTemplate {
private final RestTemplate restTemplate;
public GracefulRestTemplate(RestTemplate restTemplate) {
super(restTemplate.getMessageConverters());
this.restTemplate = restTemplate;
}
#Override
public <T> ResponseEntity<T> getForEntity(URI url, Class<T> responseType) throws RestClientException {
return withExceptionHandling(() -> restTemplate.getForEntity(url, responseType));
}
#Override
public <T> ResponseEntity<T> postForEntity(URI url, Object request, Class<T> responseType) throws RestClientException {
return withExceptionHandling(() -> restTemplate.postForEntity(url, request, responseType));
}
private <T> ResponseEntity<T> withExceptionHandling(Supplier<ResponseEntity<T>> action) {
try {
return action.get();
} catch (HttpClientErrorException ex) {
return new ResponseEntity<>(ex.getStatusCode());
}
}
}
Recently had a usecase for this. My solution:
public class MyErrorHandler implements ResponseErrorHandler {
#Override
public boolean hasError(ClientHttpResponse clientHttpResponse) throws IOException {
return hasError(clientHttpResponse.getStatusCode());
}
#Override
public void handleError(ClientHttpResponse clientHttpResponse) throws IOException {
HttpStatus statusCode = clientHttpResponse.getStatusCode();
MediaType contentType = clientHttpResponse
.getHeaders()
.getContentType();
Charset charset = contentType != null ? contentType.getCharset() : null;
byte[] body = FileCopyUtils.copyToByteArray(clientHttpResponse.getBody());
switch (statusCode.series()) {
case CLIENT_ERROR:
throw new HttpClientErrorException(statusCode, clientHttpResponse.getStatusText(), body, charset);
case SERVER_ERROR:
throw new HttpServerErrorException(statusCode, clientHttpResponse.getStatusText(), body, charset);
default:
throw new RestClientException("Unknown status code [" + statusCode + "]");
}
}
private boolean hasError(HttpStatus statusCode) {
return (statusCode.series() == HttpStatus.Series.CLIENT_ERROR ||
statusCode.series() == HttpStatus.Series.SERVER_ERROR);
}
There is no such class implementing ResponseErrorHandler in Spring framework, so I just declared a bean:
#Bean
public RestTemplate getRestTemplate() {
return new RestTemplateBuilder()
.errorHandler(new DefaultResponseErrorHandler() {
#Override
public void handleError(ClientHttpResponse response) throws IOException {
//do nothing
}
})
.build();
}
The best way to make a RestTemplate to work with 4XX/5XX errors without throwing exceptions I found is to create your own service, which uses RestTemplate :
public ResponseEntity<?> makeCall(CallData callData) {
logger.debug("[makeCall][url] " + callData.getUrl());
logger.debug("[makeCall][httpMethod] " + callData.getHttpMethod());
logger.debug("[makeCall][httpEntity] " + callData.getHttpEntity());
logger.debug("[makeCall][class] " + callData.getClazz());
logger.debug("[makeCall][params] " + callData.getQueryParams());
ResponseEntity<?> result;
try {
result = restTemplate.exchange(callData.getUrl(), callData.getHttpMethod(), callData.getHttpEntity(),
callData.getClazz(), callData.getQueryParams());
} catch (RestClientResponseException e) {
result = new ResponseEntity<String>(e.getResponseBodyAsString(), e.getResponseHeaders(), e.getRawStatusCode());
}
return result;
}
And in case of exception, simply catch it and create your own ResponseEntity.
This will allow you to work with the ResponseEntity object as excepted.