I am returning a list of products of type ListProd in my Spring Boot controller, and such object has a nested property of type List<Product> ... something like this:
public class Product implements Serializable {
int codProdct;
String dsc;
public Product(){};
// plus getters and setters (omitted for simplicity)
}
public class ListProd implements Serializable {
int codList;
List<Product> products;
public ListProd(){};
// also here getters and setters
}
and in my angular project I have the next analogoust entities:
export class Product {
public codProduct:number;
public dsc:string;
constructor(){
codProduct=null; //just for completness
dsc='';
}
}
export class ListProd {
public codList:number;
public products:Product[];
constructor(){
this.codList=null; //just for completness
this.products=null;
}
}
I'm sending a ListProd object through my Spring controller and Angular gets such an object correctly and assigns the type also correctly:
return this.http.get<ListProd>(this.apiUrl + "/getListProds", httpOptions);
but ... it is only casting correctly the parent object, when I check the type of the 'products' object (which is recived correctly, only untyped) y get type: Object
I tried to make it a Products[] in my ListProd class in java, but i get the same result. I don't know much about the 'magic' Angular does to assign those types properly, am I missing something important here? Is there a chance to force the casting on the Angular side?
Thanks in advance.
Well, if ListProd is supposed to hold array of Product[] there is a typo here.
public products:Product[];
Not knowing full extent why you use class over an interface I would advise you also to go over this. Maybe there is a reason but for being able to strong type simple interface would be better. https://www.javatpoint.com/typescript-class-vs-interface
I have a init() method that use injected private instance<>. How can I test this class using JUnit or Mockito? I tried to make some fake class and add them to a list and set this list to my private field but I have this error
java.lang.IllegalArgumentException: Can not set javax.enterprise.inject.Instance field ......
MyClass is:
#Singleton
#Startup
public class HandlerManager {
#Any
#Inject
private Instance<RollbackHandler<RollbackData>> handlers;
private RollbackHandler<RollbackData> rollbackHandler;
#PostConstruct
public void init() {
for (RollbackHandler<RollbackData> bean : handlers) {
//do something
}
}
}
Any annotation is not processed by frameworks, unless you use custom work. you will have to define all those dependencies as mocks in your test using #Mock and call injectMocks() from before test methods such as setup(). It is a multi part problem.
Use constructor injection, field injection is evil. you still will be able to annotate your constructor with #Inject.
when(provider.iterator()).thenReturn(list.iterator);
works for me.
You can create a temporary list with concrete implementations of the RollbackHandler, and mock the iterator() method of your Instance<RollbackHandler<RollbackData>> object so that it returns the iterator of the temporary list.
Example:
private void mockIterator() {
Instance<RollbackHandler<RollbackData>> handlers = mock(Instance.class);
List<RollbackHandler<RollbackData>> handlersList = Collections.singletonList(new RollbackHandlerImpl<>());
when(handlers.iterator()).thenReturn(handlersList.iterator());
}
Suppose I have two sets of controllers in Spring:
/jsonapi1/*
/jsonapi2/*
both of which return objects that are to be interpretted as JSON text.
I'd like some kind of filter to wrap the responses from one set of these controllers so that:
the original response is contained within another object.
For example, if /jsonapi1/count returns:
{"num_humans":123, "num_androids":456}
then the response should be wrapped and returned as follows:
{ "status":0,
"content":{"num_humans":123, "num_androids":456}
}
if an exception happens in the controller, then filter should catch the exception and report it as follows
{ "status":5,
"content":"Something terrible happened"
}
The responses from the other controllers are returned unchanged.
We're currently customizing a MappingJackson2HttpMessageConverter passed to WebMvcConfigurerAdapter.configureMessageConverters in order to perform the above tasks. Works great except that it doesn't seem possible for this approach to be selective about the URLs (or controller classes) it applies to.
Is it possible to apply these kinds of wrappers to individual controller classes or URLs?
Update: Servlet filters look like a solution. Is it possible chose which filter gets applied to which controller methods, or which URLs?
I was struggling on this for multiple days. The solution by #Misha didn't work for me. I was able to finally get this working using ControllerAdvice and ResponseBodyAdvice.
ResponseBodyAdvice allows to inject custom transformation logic on the response returned by a controller but before it is converted to HttpResponse and committed.
This is how my controller method looks:
#RequestMapping("/global/hallOfFame")
public List<HallOfFame> getAllHallOfFame() {
return hallOfFameService.getAllHallOfFame();
}
Now i wanted to add some standard fields around the response like devmessage and usermessage. That logic goes into the ResponseAdvice:
#ControllerAdvice
public class TLResponseAdvice implements ResponseBodyAdvice<Object> {
#Override
public boolean supports(MethodParameter returnType, Class<? extends HttpMessageConverter<?>> converterType) {
return true;
}
#Override
public Object beforeBodyWrite(Object body, MethodParameter returnType, MediaType selectedContentType,
Class<? extends HttpMessageConverter<?>> selectedConverterType, ServerHttpRequest request,
ServerHttpResponse response) {
// TODO Auto-generated method stub
final RestResponse<Object> output = new RestResponse<>();
output.setData(body);
output.setDevMessage("ResponseAdviceDevMessage");
output.setHttpcode(200);
output.setStatus("Success");
output.setUserMessage("ResponseAdviceUserMessage");
return output;
}
}
The entity classes look like this:
#Setter // All lombok annotations
#Getter
#ToString
public class RestResponse<T> {
private String status;
private int httpcode;
private String devMessage;
private String userMessage;
private T data;
}
#Entity
#Data // Lombok
public class HallOfFame {
#Id
private String id;
private String name;
}
To handle exceptions, simply create another ControllerAdvice with ExceptionHandler. Use the example in this link.
Advantages of this solution:
It keeps your controllers clean. You can support any return type from your controller methods.
Your controller return type class does not need to extend some base class as required by the AOP approach.
You do not need to hack your way through Spring filters by using HttpServletResponseWrappers. They come up with a performance penalty.
EDIT - 17th September 2019
To handle exceptions use #ExceptionHandler. Refer code below.
#ExceptionHandler(Exception.class)
#ResponseBody
public MyResponseEntity<Object> handleControllerException(HttpServletRequest request, Throwable ex) {
// default value
int httpCode = HttpStatus.INTERNAL_SERVER_ERROR.value();
if(ex instanceof ResourceNotFoundException) {
httpCode = HttpStatus.NOT_FOUND.value();
}
...
}
The way I understand your question, you have exactly three choices.
Option #1
Manually wrap your objects in simple SuccessResponse, ErrorResponse, SomethingSortOfWrongResponse, etc. objects that have the fields you require. At this point, you have per-request flexibility, changing the fields on one of the response wrappers is trivial, and the only true drawback is code repetition if many of the controller's request methods can and should be grouped together.
Option #2
As you mentioned, and filter could be designed to do the dirty work, but be wary that Spring filters will NOT give you access to request or response data. Here's an example of what it might look like:
#Component
public class ResponseWrappingFilter extends GenericFilterBean {
#Override
public void doFilter(
ServletRequest request,
ServletResponse response,
FilterChain chain) {
// Perform the rest of the chain, populating the response.
chain.doFilter(request, response);
// No way to read the body from the response here. getBody() doesn't exist.
response.setBody(new ResponseWrapper(response.getStatus(), response.getBody());
}
}
If you find a way to set the body in that filter, then yes, you could easily wrap it up. Otherwise, this option is a dead end.
Option #3
A-ha. So you got this far. Code duplication is not an option, but you insist on wrapping responses from your controller methods. I'd like to introduce the true solution - aspect-oriented programming (AOP), which Spring supports fondly.
If you're not familiar with AOP, the premise is as follows: you define an expression that matches (like a regular expression matches) points in the code. These points are called join points, while the expressions that match them are called pointcuts. You can then opt to execute additional, arbitrary code, called advice, when any pointcut or combination of pointcuts are matched. An object that defines pointcuts and advice is called an aspect.
It's great for expressing yourself more fluently in Java. The only drawback is weaker static type checking. Without further ado, here's your response-wrapping in aspect-oriented programming:
#Aspect
#Component
public class ResponseWrappingAspect {
#Pointcut("within(#org.springframework.stereotype.Controller *)")
public void anyControllerPointcut() {}
#Pointcut("execution(* *(..))")
public void anyMethodPointcut() {}
#AfterReturning(
value = "anyControllerPointcut() && anyMethodPointcut()",
returning = "response")
public Object wrapResponse(Object response) {
// Do whatever logic needs to be done to wrap it correctly.
return new ResponseWrapper(response);
}
#AfterThrowing(
value = "anyControllerPointcut() && anyMethodPointcut()",
throwing = "cause")
public Object wrapException(Exception cause) {
// Do whatever logic needs to be done to wrap it correctly.
return new ErrorResponseWrapper(cause);
}
}
The final result will be the non-repeating response wrapping that you seek. If you only want some or one controller receive this effect, then update the pointcut to match methods only within instances of that controller (rather than any class holding the #Controller annotation).
You'll need to include some AOP dependencies, add the AOP-enabling annotation in a configuration class, and make sure something component-scans the package this class is in.
Simplest way i manage custom responses from controllers is by utilising the Map variable.
so your code ends up looking like:
public #ResponseBody Map controllerName(...) {
Map mapA = new HashMap();
mapA.put("status", "5");
mapA.put("content", "something went south");
return mapA;
}
beauty of is is that you can configure it any thousand ways.
Currently i use for object transmition, custom exception handling and data reporting, too easy.
Hope this helps
I am also using AOP with #Around. Developed a custom annotation and using that for point cut. I am using a global Response. It has the status, Message and data which is of type List of type
List <? extends parent> dataList
( which can solve your class cast exception). All the entities extends this Parent class. This way I can set all the data into my List.
Also I am using the message key as param with the custom annotation and setting it in action.
Hope this helps.
I have a simple hierarchy of data objects, which have to be converted to JSON format. Like this:
#JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "documentType")
#JsonSubTypes({#Type(TranscriptionDocument.class), #Type(ArchiveDocument.class)})
public class Document{
private String documentType;
//other fields, getters/setters
}
#JsonTypeName("ARCHIVE")
public class ArchiveDocument extends Document { ... }
#JsonTypeName("TRANSCRIPTIONS")
public class TranscriptionDocument extends Document { ... }
Upon JSON parsing I encounter errors like this one:
Unexpected duplicate key:documentType at position 339. , because in the generated JSON there are actually two documentType fields.
What should be changed to make JsonTypeName value appear in documentType field, without an error (eg replacing the other value)?
Jackson version is 2.2
Your code doesn't show it, but I bet you have a getter in your Document class for the documentType property. You should annotate this getter with #JsonIgnore like so:
#JsonIgnore
public String getDocumentType() {
return documentType;
}
There is an implicit documentType property associated with each subclass, so having the same property in the parent class causes it to be serialized twice.
Another option would be to remove the getter altogether, but I assume you might need it for some business logic, so the #JsonIgnore annotation might be the best option.
I have a Struts2 Action Class configured via annotations. All of the "normal" methods that are annotated with #Action work fine.
However, I need to add a method into the action that returns JSON.
Here is a trimmed down version of my class (dao autowired with Spring):
#Namespace("featureClass")
// define success and input actions for class here
public class FeatureClassAction extends ActionSupport {
FeatureClassDao featureClassDao;
#Autowired
public setFeatureClassDao(FeatureClassDeao featureClassDao) {
this.featureClassDao = featureClassDao;
}
List<FeatureClass> featureClasses;
// snip normal actions
#Action("/featureClassesJSON")
#JSON
public String getFeatureClassesJSON() throws Exception {
featureClasses = featureClassDao.getAll();
return SUCCESS;
}
}
Can anyone assist? If I have to go the struts.xml route, that means moving all of my other actions (which work fine) into it.
I figured I would share the answer, since anyone else with the same problem would likely also face the silence.
I created two actions: FeatureClassAction and FeatureClassJsonAction. FeatureClassAction was annotated as such:
#ParentPackage("struts-default")
#Namespace("/featureClass")
public class FeatureClassAction extends ActionSupport {
FeatureClassJsonAction is annotated like this:
#ParentPackage("json-default")
#Namespace("/featureClass")
public class FeatureClassJsonAction extends ActionSupport {
The method in the JSON Action was annotated like this:
#Action(value="featureClassesJson", results = {
#Result(name="success", type="json")
})
public String getFeatureClassesJSON() throws Exception {
Hope it helps someone.