Develop Reference

Should I use #RequestBody or #RequestParam for PatchMapping

I was working on a SpringBoot Rest Api.
I've a Comment entity. I just want to update comment's text. So I decided to use patchmapping.
I'm beginner on SpringBoot. I'm learning by the training. My plan was to find the comment by given Id. And update the text as a given String parameter.
When I use this controller with #RequestBody. And send a String via postman.
#PatchMapping("/updateStatus/{id}")
public ResponseEntity<CommentDto> updateTheUserStatus(#PathVariable Long id, #RequestBody String text){
return ResponseEntity.ok(commentService.changeStatus(id, text));
}
The Postman gives 500 Internal Error. But in the Database the text field is changing as I want.
{
"timestamp": "2022-04-13T08:17:13.615+00:00",
"status": 500,
"error": "Internal Server Error",
"path": "/v1/api/comment/updateStatus/4"
}
When I use this controller with #RequestParam Postman Gives 400 Bad Request and nothing is changing.
#PatchMapping("/updateStatusMe/{id}")
public #ResponseBody ResponseEntity<CommentDto> updateTheUserStatus1(#PathVariable Long id, #RequestParam String text){
return ResponseEntity.ok(commentService.changeStatus(id, text));
}
{
"timestamp": "2022-04-13T08:19:41.391+00:00",
"status": 400,
"error": "Bad Request",
"path": "/v1/api/comment/updateStatusMe/4"
}
I know that probably I'm totally wrong. But I'm asking this question for you to learn what am I missing. Thank you for your help!

Create custom exception with custom json response in spring boot api

I would like to throw different exceptions with different Strings (giving details of the error via message) with a very specific JSON structure, something like:
[
{
"error": [
{
"statusCode": 400,
"customMessage": "xxx",
"timestamp": "time"
}
]
}
]
Is this possible to achieve with Spring Boot? I haven't found how to do it.

Create an ErrorHandler(as per your naming convention) class and extend spring class ResponseEntityExceptionHandler which receives all method exceptions. Check spring documentation for more details on this class.
In your class add handleTechincalException method as below for required exceptions.
#ExceptionHandler({ Exception.class, AbcException.class, XyzException.class })
public ResponseEntity<Object> handleTechnicalException(Exception e, WebRequest webRequest) {
// prepare response entity object as required based on type of exception
// return ResponseEntity<Object>
}

Missing request param when it is included in body

I am posting a POJO where I get an error saying the field is not included.
Asset POJO
public class Asset {
private MultipartFile[] files;
private String name;
private String meta;
//Constructor/Getters n Setters
}
Resource Method
#PostMapping("asset")
public ResponseEntity uploadAsset(#RequestParam("asset") Asset asset) {
System.out.println(asset);
return new ResponseEntity(HttpStatus.ACCEPTED);
}
PostMan JSON Body
{
"asset" : {
"files": [
"#/home/Downloads/1.jpeg",
"#/home/Downloads/2.jpeg"
],
"name": "assetName",
"meta": "assetMeta"
}
}
PostMan JSON Response
{
"timestamp": "2019-10-29T20:46:19.536+0000",
"status": 400,
"error": "Bad Request",
"message": "Required Asset parameter 'asset' is not present",
"path": "/asset"
}
I don't understand why I get the Required Asset parameter 'asset' is not present message when I have it in the JSON body. Any ideas on this?

Use #RequestBody rather than #RequestParam
public ResponseEntity uploadAsset(#RequestBody Asset asset) {

Based on your payload, Spring is expecting an object that looks like this:
public class SomeClass {
private Asset asset;
}
Change your payload to look like this:
{
"files": [
"#/home/Downloads/1.jpeg",
"#/home/Downloads/2.jpeg"
],
"name": "assetName",
"meta": "assetMeta"
}

RequestParam
Annotation which indicates that a method parameter should be bound to a web request parameter.
RequestBody
Annotation indicating a method parameter should be bound to the body of the web request. The body of the request is passed through an HttpMessageConverter to resolve the method argument depending on the content type of the request. Optionally, automatic validation can be applied by annotating the argument with #Valid.
HttpMessageConverter
Strategy interface that specifies a converter that can convert from and to HTTP requests and responses.
You need to check converter dependency. because you using application/json.
<dependency>
<groupId>com.fasterxml.jackson.core</groupId>
<artifactId>jackson-databind</artifactId>
<version>2.9.8</version>
</dependency>
Q : Missing request param when it is included in body
A : Use #RequestBody annotation.

I tried #Jordans answer and the endpoint was called with all values set to null :(
Doing more research I came across this statement https://stackoverflow.com/a/51982230/2199102 and tried it out.
Combining #Jordans answer and then the annotation change, I was able to get the answer I wanted

How to change Status code in spring boot error response?

I am making a simple rest service that makes some http calls and aggregates data using RestTemplate.
Sometimes i get NotFound error and sometimes BadRequest errors.
I want to respond with the same status code to my client and Spring seems to have this mapping out of the box. the message is okay but the Status code is always 500 Internal Server error.
I Would like to map my status code to the one i am initially receiving
"timestamp": "2019-07-01T17:56:04.539+0000",
"status": 500,
"error": "Internal Server Error",
"message": "400 Bad Request",
"path": "/8b8a38a9-a290-4560-84f6-3d4466e8d7901"
}
i would like it to be this way
"timestamp": "2019-07-01T17:56:04.539+0000",
"status": 400,
"error": "Internal Server Error",
"message": "400 Bad Request",
"path": "/8b8a38a9-a290-4560-84f6-3d4466e8d7901"
}
It throws HttpClientErrorException.BadRequest or HttpClientErrorException.NotFound
my code is a simple endpoint :
#GetMapping("/{id}")
public MyModel getInfo(#PathVariable String id){
return MyService.getInfo(id);
}

You can create global exception handling with #ControllerAdvice annotation. Like this:
#ControllerAdvice
public class RestResponseEntityExceptionHandler extends ResponseEntityExceptionHandler {
#ExceptionHandler(value = YourExceptionTypes.class)
protected ResponseEntity<Object> handleBusinessException(RuntimeException exception, WebRequest request) {
return handleExceptionInternal(exception, exception.getMessage(), new HttpHeaders(), HttpStatus.NOT_ACCEPTABLE, request);
}
}
When an exception is thrown, the handler will catch and transform it to the desired response. The original exception wont be propagated.

The accepted solution with the #ControllerAdvice is insufficient. That surely marks the response with the custom status code for the exception. It does, however, not return the wanted response body as JSON but as only simple string - the message from the exception.
To get the correct status code and the default error body the DefaultErrorAttributes can help.
#ControllerAdvice
public class PackedTemplateNotRecodableExceptionControllerAdvice extends ResponseEntityExceptionHandler {
#Autowired
private DefaultErrorAttributes defaultErrorAttributes;
#ExceptionHandler(PackedTemplateNotRecodableException.class)
public ResponseEntity<Object> handlePackedTemplateNotRecodableException(final RuntimeException exception, final WebRequest webRequest) {
// build the default error response
webRequest.setAttribute(RequestDispatcher.ERROR_STATUS_CODE, HttpStatus.BAD_REQUEST.value(), RequestAttributes.SCOPE_REQUEST);
final Map<String, Object> errorAttributes = defaultErrorAttributes.getErrorAttributes(webRequest, ErrorAttributeOptions.defaults());
// return the error response with the specific response code
return handleExceptionInternal(exception, errorAttributes, new HttpHeaders(), HttpStatus.BAD_REQUEST, webRequest);
}
}
That way you'll receive the wanted error response, e.g. something like this:
{
"timestamp": "2019-07-01T17:56:04.539+0000",
"status": 400,
"error": "Internal Server Error",
"message": "400 Bad Request",
"path": "/8b8a38a9-a290-4560-84f6-3d4466e8d7901"
}

I have spent a lot of time looking into this issue, including solutions from answers here, which didn't work for me (or I didn't implement correctly).
I finally got a breakthrough. Instead of throwing a generic Exception such as throw new Exception(message), I created classes that extends the Exception class for the specific exception type - with their respective HTTP error codes and message
#ResponseStatus(value = HttpStatus.BAD_REQUEST)
public class BadRequestException extends Exception{
public BadRequestException(String message) {
super(message);
}
}
In your application logic, you can now throw the Bad Request exception with a message like so throw new BadRequestException("Invalid Email"). This will result in an exception thrown thus :
{
"timestamp": "2021-03-01T17:56:04.539+0000",
"status": 400,
"error": "Bad Request",
"message": "Invalid Email",
"path": "path to controller"
}
You can now create other custom exception classes for the different exceptions you want, following the above example and changing the value parameter in the #ResponseStatus, to match the desired response code you want. e.g for a NOT FOUND exception #ResponseStatus (value = HttpStatus.NOT_FOUND), Java provides the different HTTP status codes via the HttpStatus enum.
For more context
I hope this is detailed enough and helps someone :)

Possible duplicate of Spring Resttemplate exception handling Your code needs a controller advice to handle the exceptions from the service it is calling.

proper way to handle dynamic responses by retrofit 2

let's say I've got a REST API which I could get list of books by invoking following retrofit 2 request.
public interface AllRecordsFromRequestInterface {
#GET("books/all")
Call<List<TrackInfo>> operation(#Header("Authorization") String authentication_token);
}
and API response:
[
{
"id": "1",
"title": "The Catcher in the Rye",
"author":"J. D. Salinger"
},
{
"id": "2",
"title": "The Great Gatsby",
"author":"F. Scott Fitzgerald"
}
]
I use GsonConverterFactory to convert json to a Model. here is my model class
public class Book{
private int id;
private String title;
private String author;
}
I'm using a authentication token to authorize myself to API as it can be seen in my request. some times other response are received rather than above response because of token expiration or something else. for example:
{
"status": "error",
"message": "Expired token"
}
what is the proper way to handle dynamic responses (with known structure) in retrofit 2?

you have multiple choices:
1-change your API:(this one is standard)
change it like this for every response and if the user failed with authentication leave the result null or if authentication was successful put the list in the result.
{
"status" : "error/success"
"message" : ...
"result" : ....
}
2- you can give Object type to retrofit and after the response was successful you can cast it to one of your models, using "instance of" syntax.
public interface AllRecordsFromRequestInterface {
#GET("books/all")
Call<Object> operation(#Header("Authorization") String authentication_token);
}