I'm new to rest webservice and have a novice q'.
I've created a rest class and would like to use helper classes to handle certain operations. So for example I've created the following service:
import statements...
#Path("/UserResources")
public class UserResource {
//Create Spring application context
static ClassPathXmlApplicationContext ctx = new
ClassPathXmlApplicationContext("classpath:/spring.xml");
private UserResourceHelper urh = new UserResourceHelper(); // this is the helper
class
UserProfileService userProfileService = ctx.getBean(UserProfileService.class);
#POST
#Path("/createUser")
#Consumes(MediaType.APPLICATION_JSON)
public Response createUser(#Context HttpServletRequest request, Object object) {
StringBuffer sb = new StringBuffer();
User user = userProfileService.findByPrimaryKey(object);
sb.append(urh.createUser(object));
return
Response.status(Status.CREATED.getStatusCode()).entity(result.toString()).build();
}
}
I have a couple of questions on this approach:
Is this the correct way to instantiate the helper class? Or should I create a constructor and instantiate the class there? for example:
public UserResource (){
urh = new UserResourceHelper();
}
On this approach will there always be a new instance of the
UserResourceHelper?
If so that would mean there will not be an issue
on concurrency correct? ie. 2 requests coming in at the same time
and the 1st object being received by the createUser method would
suddenly get replaced by the 2nd object that suddenly came in?
I'm using Hibernate for ORM. Is the way i've instantiated the entities as per my code sample correct?
Thanks for your assistance!
Related
I would like to initiate a simple POJO that generates an array of random Strings when initiated (or when the Spring Boot application starts). This array of Strings has to be shared across every controller in the Spring Boot application, and it cannot be different for different controllers. The class and methods (of this shared POJO) are internal to a Spring Boot application and are accessed by calling the getters in the controller methods (only).
Furthermore, I would like to avoid using the application.properties. The best solution would be java-only (no database such as H2 or offloading the POJO onto a file). Also, using the sessions will not help.
Something like this would help:
http://www.masterspringboot.com/security/authentication/securing-spring-boot-with-in-memory-basic-authentication
How can I accomplish such a design ?
My idea is to simply use a micro-service and launch it separately, but I would like to confirm if there is something else I can do within the single Spring Boot application.
You can create a singleton class that holds your values:
public class Main {
public static void main(String[] args) {
DataHolder dataHolder = DataHolder.getInstance();
String[] arr = dataHolder.getArr();
}
}
class DataHolder {
private static DataHolder instance = null;
private String[] arr = new String[10];
public static DataHolder getInstance() {
if (instance == null)
instance = new DataHolder();
return instance;
}
private DataHolder() {
fillArray();
}
private void fillArray() {
// use this method to fill your array
}
public String[] getArr() {
return arr;
}
}
To answer my own question, the solution was to use the in-memory provided by the mapDB, and generate all the data during the spring-boot initiating itself...
https://mvnrepository.com/artifact/org.mapdb/mapdb
The source code example can be found using the search engines...
I am writing an API using Spring Boot, and I have a abstract controller to hold the shared logic among several controllers. Now I want to add a warning field:
public abstract class BaseController<T> {
public List<String> warnings;
#RequestMapping(method = POST)
public Response create(HttpServletRequest request,HttpServletResponse response) {
warnings = new ArrayList<>();
if (something bad from T) {
warning.add("bad thing happens");
}
return createRespone(warnings);
}
(createReponse is uesd to create custom reponse)
And I have several different controller inherited from it
#RestController
#RequestMapping("/{area}/blah")
public class BlahController extends BaseController<Blah> {
}
For the warning field, will it be shared several different children controller, or will only one instance alive? If controller A and controller B are both inherited from BaseController and tried to modify warning, is it thread safe?
The warning field is not shared. Your code is equivalent to:
BaseController<blah> blahController = new BlahController();
BaseController<noh> nohController = new NohController();
Having state in a controller is against the REST concepts.
I'd like you ask a few questions and ask you for advice:
I want to test my public method (I use Spring Boot, Mockito, JUnit):
#Service
public class MyClass{
public Long getClientId(List<String> nameSurname) throws AuthorizationException {
Long operatorId;
if(...){
(... something not interesting ...)
User user = getUserByLogin("AnthonyGates2");
operatorId = nonNull(user) ? user.getOperatorId() : null;
} else {
List<User> users = getUserListByLogin("AnthinyGates");
operatorId = isNotEmpty(users) ? return operatorId;
return operatorId;
}
How to test the method getClientId?
Methods getUserByLogin and getUserListByLogin are private in this class (MyClass) but I have to mock the results of these private methods because these methods retrieve data from an external service.
These private methods looks like:
User user = DelegateImpl.getDelegate().getUserByLogin(nameAndSurname);
DelegateImpl.getDelegate().getUserByLogin get data from database and that data have to be mocked like:
when(DelegateImpl.getDelegate().getUserByLogin(any())).thenReturn(user);
How can I test my public class? Should I use PowerMock/PowerMockito? Making these methods public is in my opinion ugly because these methods are called only in MyClass. I can't find a good tutorial in Internet for my case (Spring Boot, Mockito, JUnit).
Thank you very much for all your tips!
Best regards
Matthew
Test the unit only by calling the public methods. I think that your example is a class in the service layer (contains business logic) and the two getUser... methods should be in a different class (I think in the data layer) where they can be public. Inject that class via the constructor as a dependency (in the service object) so you can mock it when testing the service class. The data layer class (with the getUser... methods) can also be tested by it's own unit tests.
If you are not able to unit test a method/class then it most probably means that it just does too much. Try extracting your private methods to a separate class. It does not need to be public - you can e.g. have it package-local in the same package.
Later, in the test, you would have to inject a mock of this class and simulate its behaviour.
The setup of MyClass in its unit test could look similar to this:
AnotherClass anotherClassMock = Mockito.mock(AnotherClass.class);
MyClass myClass = new MyClass(anotherClassMock);
Where AnotherClass would have methods getUserListByLogin and getUserByLogin.
EDIT:
It seems that the logic within in your private methods already call an external class. The problem is that you obtain an instance of an object via a call to a static getDelegate() method in another class.
Here's what you can do:
Create a new field in MyClass which would have the same type as the one returned by getDelegate() method (I don't know what that is, I'll call it Delegate)
Have 2 constructors: a default one which would assign the result of getDelegate method to your new field and another one which would take an instance of Delegate as a parameter and assign it to your field
In tests use the second constructor to create an instance of MyClass and pass a mock of Delegate class
It would look more ore less like this:
class MyClass() {
private Delegate delegate;
MyClass() {
this.delegate = DelegateImpl.getDelegate();
}
MyClass(Delegate delegate) {
this.delegate = delegate;
}
// ... the rest
}
I am totally confused with one issue Spring data + hibernate
We have a Restful service which we are migrating to V2.
So the old controller looks like
#Api(tags = {"assignments"})
#RestController
#CheckedTransactional
public class AssignmentListController {
#Inject
private AssignmentListService assignmentListService;
//REST function
public list() {....}
}
The REST function list calls AssignmentListService to load assignments, which is a collection, and loads some data lazily. Its works excellent.
What I did is I copied this controller as name AssignmentListControllerV2, and it looks like
#Api(tags = {"assignments"})
#RestController
#CheckedTransactional
public class AssignmentListControllerV2 {
#Inject
private AssignmentListService assignmentListService;
#Inject
private AssignmentDtoMapper assignmentDtoMapper;
public list() {...}
}
The code is same except AssignmentDtoMapper bean added, which is created using MapStruct.
Now the problem, When I call this new service, somehow I get a Lazy Load exception. The error is
could not initialize proxy - no Session
I desperately need some help as I have no clue whats happening. I have just copied the code in a new class and its failing.
The exception is actually pretty clear, Hibernate can't load the lazy fetched member because there is no persistence context open when you hit it.
I suppose that in the V2 the:
#Inject
private AssignmentDtoMapper assignmentDtoMapper;
is to change some JPA business entity into DTO?
It's probably the source of the exception if you try to map not loaded member there.
If you want to avoid the exception on unitiliazed proxy you can try something like
public boolean isProxyInitialized(Object obj){
if(obj instanceof HibernateProxy){
HibernateProxy proxy = (HibernateProxy) obj;
return !proxy.getHibernateLazyInitializer().isUninitialized();
}
return obj != null;
}
It should return true if the member as bean fetched otherwise false.
I have a Spring MVC web application with conroller like below :
#Controller
public class ActionRestController {
#RequestMapping(value = "/list", method = GET)
#ResponseBody
public List<Action> list(Action action, SearhCriteria searchCriteria) {
List<Action> ret = new ArrayList<Action>();
// Call a service method to get the records
// Copy the records into the list
// return the list of objects
return ret;
}
The Controller is invoked when the user does a search. There are several such controllers in the app, one for each searchable entity.
For reasons that I cannot explain very well, here, I cannot modify these controllers in anyway.
But now, I have requirement in the UI to display the search criteria and the no. of records and paging details, as well. This information is not returned by the controller. The JSON returned by the Controller contains just the list of records.
I have put up a different controller which will handle the request, gets and puts the extra info in the model and forwards the request to the existing controller like below :
#Controller
public class ActionExtendedController {
#RequestMapping(value = "/searchlist", method = GET)
#ResponseBody
public List<Action> list(Action action, SearhCriteria searchCriteria, Model model) {
model.addAttribute("searchParameters", searchCriteria);
return "forward:/list";
}
Upto this point, all is well.
What I want to do is intercept the request at a point where the List is returned from the controller, before it is converted to JSON, and return a map containing the list and the search parameters.
Now since the 'immutable' controller users ResponseBody the control goes to the JacksonMessageConverter amd the response goes out from there. I have already tried the following paths and they do not work.
Interceptor - By the time I get here, the response is already written out, so there is no way to change it.
Custom ObjectMapper for the JasksonMessageConverter - Will not work, since I do not have access to the model object inside the mapper, I only have access to the list returned by the controller.
Aspect #After pointcut for the controller - I think this technique will work, but I cannot get it to work. The advise does not fire and I am sure I am missing something in the configuration.
Is there a way to get Spring AOP to fire on a annotated controller, handler method or
can anyone suggest another method of intercepting the handler return value (along with the model) ?
How about a simple delegation to the base controller in your extended controller:
#Controller
public class ActionExtendedController {
#Autowired ActionRestController baseRestController;
#Autowired MappingJacksonJsonView mappingJacksonJsonView;
#RequestMapping(value = "/searchlist", method = GET)
public View list(Action action, SearhCriteria searchCriteria, Model model) {
List<Action> actions = baseRestController.list(action, searchCriteria, model);
model.addAttribute("actions", actions);
model.addAttribute("searchParameters", searchCriteria);
return mappingJacksonJsonView;
}
this way you are delegating to the original controller, but using this new controller for the view. Just register a mappingJacksonJsonView as a bean also which will serialize all model objects (searchcriteria and actions) into the json view. You need not even return a view but can also use #ResponseBody, with a type that can hold the responses and search criteria.
Why don't you change the return type to a Map? Like:
#Controller
public class ActionRestController {
#RequestMapping(value = "/list", method = GET)
#ResponseBody
public Map<String, Object> list(Action action, SearhCriteria searchCriteria) {
Map<String, Object> map = new HashMap<String, Object>();
List<Action> ret = new ArrayList<Action>();
// Call a service method to get the records
// Copy the records into the list
// return the list of objects
map.put("searchResult",ret);
map.put("searchCriteria", searchCriteria);
return map;
}