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What's the best way to encode and decode parameter in springboot?

I use #RequestParam to get the parameter value,but I find the if I pass the value like 'name=abc&def&id=123',I will get the name value 'abc' instead of 'abc&def'. I find the encode and decode the parameter value can solve my problem.But I have to write the encode and decode mehtod in every controller method,Do spring have the global mehtod that decode every #RequestParam value?When using #RequestParam, is it necessary to encode and decode every value?
Here is my code:
#PostMapping("/getStudent")
public Student getStudent(
#RequestParam String name,
#RequestParam String id) {
name= URLDecoder.decode(name, "UTF-8");
//searchStudent
return Student;
}
#PostMapping("/getTeacher")
public teacher getTeacher(
#RequestParam String name,
#RequestParam String teacherNo) {
name= URLDecoder.decode(name, "UTF-8");
//searchTeacher
return teacher;
}
Somebody say the the Spring will have already done this,but I have try,the result is not right.Only use curl cmd is ok,but java code is not ok.
#PostMapping(value = "/example")
public String handleUrlDecode1(#RequestParam String param) {
//print ello%26test
System.out.println("/example?param received: " + param);
return "success";
}
#GetMapping(value = "/request")
public String request() {
String url = "http://127.0.0.1:8080/example?param=ello%26test";
System.out.println(url);
RestTemplate restTemplate = new RestTemplate();
return restTemplate.postForObject(url, null, String.class);
}

You must create an HTTP entity and send the headers and parameter in body.
#GetMapping(value = "/request")
public String request() {
String url = "http://127.0.0.1:8080/example";
System.out.println(url);
RestTemplate restTemplate = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
MultiValueMap<String, String> map= new LinkedMultiValueMap<String, String>();
map.add("param","ello&test");
map.add("id","ab&c=def");
HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<MultiValueMap<String, String>>(map, headers);
return restTemplate.postForObject(url, request, String.class);
}

As you can read here, the escape character for & is %26.
So you should use the following
name=abc%26def&id=123
If you don't use an escape character according to URL standards, Spring will try to use what follows & and try to match it as a new query parameter.

No need to manually use URLDecoder, SpringBoot controllers will handle it for you.
#RestController
public class UrlDecodeController {
#GetMapping(value = "/example")
public String handleUrlDecode(#RequestParam String param) {
System.out.println("/example?param received: " + param);
return "success";
}
#PostMapping(value = "/example2")
public String handleUrlDecodeInPostRequest(#RequestParam String param1, ExamplePayload payload) {
System.out.println("/example2?param1 received: " + param1);
System.out.println("request body - value1: " + payload.getValue1());
return "success";
}
#GetMapping(value = "/request")
public String request() {
String url = "http://localhost:8080/example2?param1=test1&test2";
System.out.println(url);
RestTemplate restTemplate = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);
MultiValueMap<String, String> map = new LinkedMultiValueMap<String, String>();
map.add("value1","test1&test2");
HttpEntity<MultiValueMap<String, String>> request = new HttpEntity<MultiValueMap<String, String>>(map, headers);
return restTemplate.postForObject(url, request, String.class);
}
class ExamplePayload{
private String value1;
private String value2;
//getters and setters
public ExamplePayload() {
}
}
}
Call with GET /example?param=hello%26test and the System.out.println outputs:
/example?param received: hello&test
Call the POST using curl as an example:
curl -X POST "http://localhost:8080/example2?param1=test1%26test2" -d "value1=test3%26test4"
Prints:
/example2?param1 received: test1&test2
request body - value1: test3&test4
Added GET /request to show using RestTemplate with the application/x-www-form-urlencoded Content-Type. Note that RestTemplate will automatically url encode any values passed as request parameters or in the request body. If you pass a String value of "%26" it will pass it as is, this is what you are seeing in your example. If you pass "&" it will url encode it to "%26" for you, and the Controller decodes it automatically on the other side.

SpringBoot response charset errors

i got some problems with my SpringBoot REST Controller. This simply does a http GET call to our database and should return a simple String / json. when i call the URL simply in my browser or via my angular 3 app, the response has some charset errors and i don't know, how to fix them.
I suggest, it is a UTF-8 problem.
First to show you the output:
this is how it comes from the Controller: MeinekestraÃe
and it should be Meinekestraße
here is a part of my SpringBoot Controller:
#Controller
public class RecieverController {
#Value("${server}")
private String server;
#Value("${user.token}")
private String token;
#RequestMapping(value="/reciever", method=RequestMethod.GET, produces = "text/plain;charset=UTF-8")
#ResponseBody
#CrossOrigin(origins = "http://localhost:4200", maxAge = 3600)
public String getRecieverData(
#RequestHeader(value="Accept") String accept,
#RequestHeader(value="Host") String host) {
final String url = server + "/rest/client/profile";
RestTemplate restTemplate = new RestTemplate();
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON_UTF8);
headers.set("Auth-Token", token); // user_token
HttpEntity<String> entity = new HttpEntity<String>("parameters", headers);
ResponseEntity<String> response = restTemplate.exchange(url, HttpMethod.GET, entity, String.class);
return response.getBody();
}}
I tried the following things, but nothing changed in the output.
spring.http.encoding.charset=UTF-8
spring.http.encoding.enabled=true
spring.http.encoding.force=true
or this
RestTemplate restTemplate = new RestTemplate();
restTemplate.getMessageConverters()
.add(0, new StringHttpMessageConverter(Charset.forName("UTF-8")));
any other ideas what could be the problem? the database isnt the issue. Everything is stored correctly there.
Edit:
this is the screenshot of the header from the output
and a part from the json output:
The Problem could be solved by adding both
spring.http.encoding.charset=UTF-8
spring.http.encoding.enabled=true
spring.http.encoding.force=true
and this
RestTemplate restTemplate = new RestTemplate();
restTemplate.getMessageConverters()
.add(0, new StringHttpMessageConverter(Charset.forName("UTF-8")));
Thanks #dienerd for helping me via chat

For the ones looking for a way to force encoding request/response in #RestController in a Spring Boot project.
spring.http.encoding.charset=UTF-8
spring.http.encoding.enabled=true
spring.http.encoding.force=true
is deprecated, in your application.yaml or application.properties use the following:
server.servlet.encoding.charset=UTF-8
server.servlet.encoding.force=true
This did the trick for me.

How to extract HTTP status code from the RestTemplate call to a URL?

I am using RestTemplate to make an HTTP call to our service which returns a simple JSON response. I don't need to parse that JSON at all. I just need to return whatever I am getting back from that service.
So I am mapping that to String.class and returning the actual JSON response as a string.
RestTemplate restTemplate = new RestTemplate();
String response = restTemplate.getForObject(url, String.class);
return response;
Now the question is -
I am trying to extract HTTP Status codes after hitting the URL. How can I extract HTTP Status code from the above code? Do I need to make any change into that in the way I doing it currently?
Update:-
This is what I have tried and I am able to get the response back and status code as well. But do I always need to set HttpHeaders and Entity object like below I am doing it?
RestTemplate restTemplate = new RestTemplate();
//and do I need this JSON media type for my use case?
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
//set my entity
HttpEntity<Object> entity = new HttpEntity<Object>(headers);
ResponseEntity<String> out = restTemplate.exchange(url, HttpMethod.GET, entity, String.class);
System.out.println(out.getBody());
System.out.println(out.getStatusCode());
Couple of question - Do I need to have MediaType.APPLICATION_JSON as I am just making a call to url which returns a response back, it can return either JSON or XML or simple string.

Use the RestTemplate#exchange(..) methods that return a ResponseEntity. This gives you access to the status line and headers (and the body obviously).
getStatusCode()
getHeaders()

If you don´t want to leave the nice abstraction around RestTemplate.get/postForObject... methods behind like me and dislike to fiddle around with the boilerplate stuff needed when using RestTemplate.exchange... (Request- and ResponseEntity, HttpHeaders, etc), there´s another option to gain access to the HttpStatus codes.
Just surround the usual RestTemplate.get/postForObject... with a try/catch for org.springframework.web.client.HttpClientErrorException and org.springframework.web.client.HttpServerErrorException, like in this example:
try {
return restTemplate.postForObject("http://your.url.here", "YourRequestObjectForPostBodyHere", YourResponse.class);
} catch (HttpClientErrorException | HttpServerErrorException httpClientOrServerExc) {
if(HttpStatus.NOT_FOUND.equals(httpClientOrServerExc.getStatusCode())) {
// your handling of "NOT FOUND" here
// e.g. throw new RuntimeException("Your Error Message here", httpClientOrServerExc);
}
else {
// your handling of other errors here
}
The org.springframework.web.client.HttpServerErrorException is added here for the errors with a 50x.
Now you´re able to simple react to all the StatusCodes you want - except the appropriate one, that matches your HTTP method - like GET and 200, which won´t be handled as exception, as it is the matching one. But this should be straight forward, if you´re implementing/consuming RESTful services :)

If you want all the HTTPStatus from a RestTemplate including 4XX and 5XX, you will have to provide an ResponseErrorHandler to the restTemplate, since the default handler will throw an exception in case of 4XX or 5XX
We could do something like that :
RestTemplate restTemplate = new RestTemplate();
restTemplate.setErrorHandler(new DefaultResponseErrorHandler() {
#Override
public boolean hasError(HttpStatus statusCode) {
return false;
}
});
ResponseEntity<YourResponse> responseEntity =
restTemplate.getForEntity("http://your.url.here", YourResponse.class);
assertThat(responseEntity.getStatusCode()).isEqualTo(HttpStatus.XXXX);

private RestTemplate restTemplate = new RestTemplate();
ResponseEntity<String> response = restTemplate.exchange(url,HttpMethod.GET, requestEntity,String.class);
response contains 'body', 'headers' and 'statusCode'
to get statusCode : response.getStatusCode();

exchange(...) works but if you want less code, you can use
org.springframework.boot.test.web.client.TestRestTemplate.getForEntity(...)
which returns an Entity containing StatusCode. Change your example code to this:
RestTemplate restTemplate = new RestTemplate();
ResponseEntity<String> response = restTemplate.getForEntity(url, String.class);
HttpStatus statusCode = response.getStatusCode();
To test it you can use this snippet from my unit test:
ResponseEntity<String> response = restTemplate.getForEntity(url, String.class);
assertResponseHeaderIsCorrect(response, HttpStatus.OK);
/**
* Test the basics of the response, non-null, status expected, etc...
*/
private void assertResponseHeaderIsCorrect(ResponseEntity<String> response, HttpStatus expectedStatus) {
assertThat(response).isNotNull();
assertThat(response.getHeaders().getContentType()).isEqualTo(MediaType.APPLICATION_JSON_UTF8);
assertThat(response.getStatusCode()).isEqualTo(expectedStatus);
}

There can be some slightly trickier use cases someone might fall in (as I did). Consider the following:
Supporting a Page object in order to use it with RestTemplate and ParameterizedTypeReference:
RestPageResponse:
import java.util.ArrayList;
import java.util.List;
import org.springframework.data.domain.PageImpl;
import org.springframework.data.domain.Pageable;
public class RestResponsePage<T> extends PageImpl<T>{
private static final long serialVersionUID = 3248189030448292002L;
public RestResponsePage(List<T> content, Pageable pageable, long total) {
super(content, pageable, total);
}
public RestResponsePage(List<T> content) {
super(content);
}
public RestResponsePage() {
super(new ArrayList<T>());
}
}
Using ParameterizedTypeReference will yield the following:
ParameterizedTypeReference<RestResponsePage<MyObject>> responseType =
new ParameterizedTypeReference<RestResponsePage<MyObject>>() {};
HttpEntity<RestResponsePage<MyObject>> response = restTemplate.exchange(oauthUrl, HttpMethod.GET, entity, responseType);
Calling #exchange:
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.MULTIPART_FORM_DATA);
HttpEntity<?> entity = new HttpEntity<>(headers);
response = restTemplate.exchange("localhost:8080/example", HttpMethod.GET, entity, responseType);
Now here is the "tricky" part.
Trying to call exchange's getStatusCode will be impossible because the compiler, unfortunately, will be unaware of the "intended" type of response.
That is because generics are implemented via type erasure which removes all information regarding generic types during compilation (read more - source)
((ResponseEntity<RestResponsePage<MyObject>>) response).getStatusCode()
In this case, you have to explicitly cast the variable to the desired Class to get the statusCode (and/or other attributes)!

Putting this much of code is enough for me
HttpStatus statusCode = ((ResponseEntity<Object>) responseOfEsoft).getStatusCode();

You can use this solution
RestTemplate restTemplate = new RestTemplate();
final String baseUrl = "http://www.myexampleurl.com";
URI uri = new URI(baseUrl);
ResponseEntity<String> result = restTemplate.getForEntity(uri, String.class);
//get status code
int statuCode = result.getStatusCodeValue();

Was able to solve this through:
HttpEntity<Object> entity = restTemplate.getForEntity(uri, Object.class);
ResponseEntity<String> result = restTemplate.exchange(uri, HttpMethod.GET, entity, String.class);
System.out.println(result.getStatusCode());

Why RestTemplate GET response is in JSON when should be in XML?

I struggled with an extrange spring behavior using RestTemplate (org.springframework.web.client.RestTemplate) without success.
I use in my hole application below code and always receive an XML response, which I parse and evaluate its result.
String apiResponse = getRestTemplate().postForObject(url, body, String.class);
But can't figure out why a server response is in JSON format after executing:
String apiResponse = getRestTemplate().getForObject(url, String.class);
I've debugged at low level RestTemplate and the content type is XML, but have no idea why the result is in JSON.
When I access from a browser the response is also in XML, but in apiResponse I got JSON.
I tried many options after reading Spring documentation
http://docs.spring.io/spring/docs/3.0.x/api/org/springframework/web/client/RestTemplate.html
Also tried to modify explicitly the headers but still can't figure it out.
I debugged RestTemplate class and noticed that this method is always setting application/json:
public void doWithRequest(ClientHttpRequest request) throws IOException {
if (responseType != null) {
List<MediaType> allSupportedMediaTypes = new ArrayList<MediaType>();
for (HttpMessageConverter<?> messageConverter : getMessageConverters()) {
if (messageConverter.canRead(responseType, null)) {
List<MediaType> supportedMediaTypes = messageConverter.getSupportedMediaTypes();
for (MediaType supportedMediaType : supportedMediaTypes) {
if (supportedMediaType.getCharSet() != null) {
supportedMediaType =
new MediaType(supportedMediaType.getType(), supportedMediaType.getSubtype());
}
allSupportedMediaTypes.add(supportedMediaType);
}
}
}
if (!allSupportedMediaTypes.isEmpty()) {
MediaType.sortBySpecificity(allSupportedMediaTypes);
if (logger.isDebugEnabled()) {
logger.debug("Setting request Accept header to " + allSupportedMediaTypes);
}
request.getHeaders().setAccept(allSupportedMediaTypes);
}
}
}
Could you give an idea?

I could solve my issue with RC.'s help. I'll post the answer to help other people.
The problem was that Accept header is automatically set to APPLICATION/JSON so I had to change the way to invoke the service in order to provide the Accept header I want.
I changed this:
String response = getRestTemplate().getForObject(url, String.class);
To this in order to make the application work:
// Set XML content type explicitly to force response in XML (If not spring gets response in JSON)
HttpHeaders headers = new HttpHeaders();
headers.setAccept(Arrays.asList(MediaType.APPLICATION_XML));
HttpEntity<String> entity = new HttpEntity<String>("parameters", headers);
ResponseEntity<String> response = getRestTemplate().exchange(url, HttpMethod.GET, entity, String.class);
String responseBody = response.getBody();

Sending GET request with Authentication headers using restTemplate

I need to retrieve resources from my server by sending a GET request with some Authorization headers using RestTemplate.
After going over the docs I noticed that none of the GET methods accepts headers as a parameter, and the only way to send Headers such as accept and Authorization is by using the exchange method.
Since it is a very basic action I am wondering if I am missing something and there another, easier way to do it?

You're not missing anything. RestTemplate#exchange(..) is the appropriate method to use to set request headers.
Here's an example (with POST, but just change that to GET and use the entity you want).
Here's another example.
Note that with a GET, your request entity doesn't have to contain anything (unless your API expects it, but that would go against the HTTP spec). It can be an empty String.

You can use postForObject with an HttpEntity. It would look like this:
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
headers.set("Authorization", "Bearer "+accessToken);
HttpEntity<String> entity = new HttpEntity<String>(requestJson,headers);
String result = restTemplate.postForObject(url, entity, String.class);
In a GET request, you'd usually not send a body (it's allowed, but it doesn't serve any purpose). The way to add headers without wiring the RestTemplate differently is to use the exchange or execute methods directly. The get shorthands don't support header modification.
The asymmetry is a bit weird on a first glance, perhaps this is going to be fixed in future versions of Spring.

Here's a super-simple example with basic authentication, headers, and exception handling...
private HttpHeaders createHttpHeaders(String user, String password)
{
String notEncoded = user + ":" + password;
String encodedAuth = "Basic " + Base64.getEncoder().encodeToString(notEncoded.getBytes());
HttpHeaders headers = new HttpHeaders();
headers.setContentType(MediaType.APPLICATION_JSON);
headers.add("Authorization", encodedAuth);
return headers;
}
private void doYourThing()
{
String theUrl = "http://blah.blah.com:8080/rest/api/blah";
RestTemplate restTemplate = new RestTemplate();
try {
HttpHeaders headers = createHttpHeaders("fred","1234");
HttpEntity<String> entity = new HttpEntity<String>("parameters", headers);
ResponseEntity<String> response = restTemplate.exchange(theUrl, HttpMethod.GET, entity, String.class);
System.out.println("Result - status ("+ response.getStatusCode() + ") has body: " + response.hasBody());
}
catch (Exception eek) {
System.out.println("** Exception: "+ eek.getMessage());
}
}

These days something like the following will suffice:
HttpHeaders headers = new HttpHeaders();
headers.setBearerAuth(accessToken);
restTemplate.exchange(RequestEntity.get(new URI(url)).headers(headers).build(), returnType);

All of these answers appear to be incomplete and/or kludges. Looking at the RestTemplate interface, it sure looks like it is intended to have a ClientHttpRequestFactory injected into it, and then that requestFactory will be used to create the request, including any customizations of headers, body, and request params.
You either need a universal ClientHttpRequestFactory to inject into a single shared RestTemplate or else you need to get a new template instance via new RestTemplate(myHttpRequestFactory).
Unfortunately, it looks somewhat non-trivial to create such a factory, even when you just want to set a single Authorization header, which is pretty frustrating considering what a common requirement that likely is, but at least it allows easy use if, for example, your Authorization header can be created from data contained in a Spring-Security Authorization object, then you can create a factory that sets the outgoing AuthorizationHeader on every request by doing SecurityContextHolder.getContext().getAuthorization() and then populating the header, with null checks as appropriate. Now all outbound rest calls made with that RestTemplate will have the correct Authorization header.
Without more emphasis placed on the HttpClientFactory mechanism, providing simple-to-overload base classes for common cases like adding a single header to requests, most of the nice convenience methods of RestTemplate end up being a waste of time, since they can only rarely be used.
I'd like to see something simple like this made available
#Configuration
public class MyConfig {
#Bean
public RestTemplate getRestTemplate() {
return new RestTemplate(new AbstractHeaderRewritingHttpClientFactory() {
#Override
public HttpHeaders modifyHeaders(HttpHeaders headers) {
headers.addHeader("Authorization", computeAuthString());
return headers;
}
public String computeAuthString() {
// do something better than this, but you get the idea
return SecurityContextHolder.getContext().getAuthorization().getCredential();
}
});
}
}
At the moment, the interface of the available ClientHttpRequestFactory's are harder to interact with than that. Even better would be an abstract wrapper for existing factory implementations which makes them look like a simpler object like AbstractHeaderRewritingRequestFactory for the purposes of replacing just that one piece of functionality. Right now, they are very general purpose such that even writing those wrappers is a complex piece of research.

A simple solution would be to configure static http headers needed for all calls in the bean configuration of the RestTemplate:
#Configuration
public class RestTemplateConfig {
#Bean
public RestTemplate getRestTemplate(#Value("${did-service.bearer-token}") String bearerToken) {
RestTemplate restTemplate = new RestTemplate();
restTemplate.getInterceptors().add((request, body, clientHttpRequestExecution) -> {
HttpHeaders headers = request.getHeaders();
if (!headers.containsKey("Authorization")) {
String token = bearerToken.toLowerCase().startsWith("bearer") ? bearerToken : "Bearer " + bearerToken;
request.getHeaders().add("Authorization", token);
}
return clientHttpRequestExecution.execute(request, body);
});
return restTemplate;
}
}