I'm new to spring boot and was referring to this article. It asks to add #JsonInclude(Include.NON_NULL) annotation to remove null attributes from response body, however I'm interested in removing null attributes from request body.
Please suggest how can I achieve that.
The request body is:
{
"userUuid": "2u9k2ld8f-ghj47dhj",
"suggestion": null
}
and the request DTO class is:
#Data
#NoArgsConstructor
public class UserRequestDTO implements Serializable {
private String userUuid;
#JsonInclude(JsonInclude.Include.NON_NULL)
private String suggestion;
}
Clearly it is not working for me. When I stringify and print the request body, it includes suggestion attr which is null.
Thank you for any help.
Well... Do not use toString() use Jackson ObjectMapper. So like:
var objectMapper = new ObjectMapper();
var dto = objectMapper.readValue(JSON, UserRequestDTO.class);
var strNoNullFields = objectMapper.writeValueAsString(dto);
That way the annotation is working.
Anyway this is not something very optimal. You might want to re-think your design how to calculate checksum (your question smells a bit like XY-problem).
I need to generate the checksum of the payload excluding the null attrs. I do not want to replace null attr rather remove it. To generate the signature I will to doing .toString() on the request body
I think you are looking for a request has dynamic attributes.
Try use a HashMap<String,Object> on parameters.
Other simple way is overriding toString() from DTO and ignore null attrs.
Suggestions: Besides using this only for logging I think both is bad practice could be better create a method generateSignature() handles all rules of this.
Related
I am stuck with a basic confusion which I cannot test and cannot find a straightforward answer to as well.
I have an endpoint PUT which expects an object in the body , RequestObject.
It consists of 1 field only.
class RequestObject {
String name;
}
Now from the service from which I am hitting this endpoint, the object that I am supposed to use to send in the request has 2 fields.
class Test {
String firstname;
String age;
}
If I make a request, with age as null,
Will this work ?
Since firstName and name are not the same "spellings", will the mapping happen automatically ?
I am assuming No for both but I am not sure how to confirm.
WIll appreciate if someone can point me in right direction.
Thanks
#JsonIgnoreProperties(ignoreUnknown = true)
class RequestObject {
#JsonProperty("firstname")
String name;
}
By default Spring Boot uses the Jackson library to convert to objects. You can customize it using annotations. See https://github.com/FasterXML/jackson-annotations/wiki/Jackson-Annotations
So, I have a controller which takes in a request parameter and a body. The request body can be of various class types depending on the type of parameter. Currently I am using JsonNode for the body which works fine. Looks like this :
#PostMapping() public ResponseEntity<Response> save(#RequestParam("request type") RequestProcess process, #Valid #RequestBody JsonNode requestJson) {
I want to know whether it's possible to provide the body with the class type depending on the param provided. If yes how do I do it?
If this is not possible in REST, is there a chance I might be able to do this using GraphQl. I don't know much about GraphQL still researching.
TIA
The nearer you can reach is by using generics
class Controller < T > {
#PostMapping("/save")
ResponseEntity < Response > save(#RequestBody T requestJson) {}
}
We have a service that simply returns the json document on a GET request. Since we do not have the POJO for the response "model", it appears we won't be able to use the auto response fields generation "goodness".
One option for us is to create the Pojos (quite large, about 50 attributes) and a corresponding controller that uses the pojos. This is awkward as we now have to maintain the model and corresponding controller just so we can auto generate the model.
Any ideas on how we can still leverage some auto generation of the response fields would be greatly appreciated.
Here's the controller I'm referring to:
#RestController
#RequestMapping("/api")
public class ProductController {
#Autowired
ProductService productService;
#RequestMapping(value = { "/products/{ids}" }, method = { RequestMethod.GET },
produces = "application/json", headers={"accept=application/json"})
#Timed
#ExceptionMetered
#LogExecutionTime
public String getProductDetails(#PathVariable("id") String id) {
return productService.getProductDetails(id);
}
At the moment I see no way of leveraging the auto generation without putting additional effort into it. Spring Auto REST Docs works by inspecting POJOs with a Jackson visitor (static introspection without runtime information) and there is currently no way of deriving the JSON fields from a string (would be dynamic at runtime). Thus, I only see two options:
The approach that you already described: Creating the corresponding POJO and using it.
Using Spring REST Docs for the corresponding test and manually document each field in the test. Might be the better option here if you do not want to alter the production code.
I have a Rest Controller with an optional #RequestBody parameter, that I want to initialize if a user does not specify it. Now I'm doing this:
#PostMapping
public ResponseEntity<Page<?>> findAll(
#RequestBody(required=false) MyRequest request,
Pageable pageable
) {
if (request == null) {
request = new MyRequest();
}
...
}
Is there any automatic way to tell Spring MVC that in case the parameter is null it must create a new object?
I don't full control Spring but I think there is not an automatic way to initialize an object like this. If the body is empty, the message converter initializes an object with null value. That's why you have a NPE.
You can use the Java 8 Optional<Myrequest> even if I've never use it in this case and I'll be curious to know how the message converter treats this case. If you test it, please let me know.
Remember #RequestBody calls the empty constructor of MyRequest. Therefore request will always reference to an instance of that class.
Conclusion: There is no way request == null or request.equals(null) evaluates to true.
I'm facing a problem with Spring and restTemplate. I want to send an object (ListResponse) that contains a generic array. The defenition is as follow:
public class ListResponse<T> implements Serializable {
private long total;
private int page;
private int pageSize;
private T[] objects;
I send a request whith restTemplate.getForObject(). As a result I get an object of type ListResponse but the objects array contains an array of LinkedHashMaps instead of an array with objects of type T.
It seems like restTemplate can not convert the elements in the array to their correct type.
How can I make sure that I get an array of objects of type T back ?
I had this problem today and here is the solution that I came up with (actually, that one of my co-workers suggested). We use it with an interface that returns List<MyDto>.
When you call the RestTemplate, don't pass in the generic type.
Define: public class MyDtoListTemplate extends ListTemplate<MyDto>
Then, call
MyDtoListTemplate template = restTemplate.getForObject("url", MyDtoListTemplate .class, mapOfPathVariables);
It's a bummer that you have to define a concrete class that extends/implements the generic type, but then the generic information is available to the jackson deserializer.
I remember I was able to deserialize generic classes with Jackson 2. I had to add MappingJackson2HttpMessageConverter converter to RestTemplate before making any Http calls with it.
RestTemplate template = new RestTemplate();
template.getMessageConverters().add(new MappingJackson2HttpMessageConverter());
Unfortunately there's no easy way of doing it that I know of. The problem is that the RestTemplate is told which object type to expect. As long as all the fields in this object has a corresponding element in the json/xml, everything works fine. In the case of generics, the serializer doesn't know which class to expect so it just turns the map it gets to a java Map.
You will have the same problem if you tried to getForObject for a generic return type.