Suppose I have this:
#Transactional(rollbackFor = NotificationException.class)
public interface PersonManagerService {
public void addPerson(Person person);
}
and an implementation:
public class PersonManagerServiceImpl implements PersonManagerService {
public OtherService otherService;
public void addPerson(Person person) {
// stuff
}
// getter and setter for otherService
}
How would I go about mocking the otherService dependency while still having the addPerson method hit the database?
My scenario is that I want to test that a particular exception causes a rollback of the saving of the person that is being added. This exception would come from the OtherService class, which I don't want to call the real version of. I am currently using Spring Transaction annotations so I have a test like this:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(locations = {various locations})
public class Test() {
#Autowired
PersonManagerService service;
#Test
public void test() {
// how to call setOtherService so it can be a mock?
}
If I try to cast the auto wired bean, I get an IllegalArgumentException because it is a proxy. If I made the Impl not use an interface, I could use CGLIB but I don't want to do that. If I create the impl programmatically, then it's not tied into the transaction flow. What other options do I have?
There are various ways you can tackle this program (from best to worst):
take advantage of #Profiles - in Spring 3.1 you can associate profile name with every bean. When you are starting an application context you provide active profiles and only beans without any profile associated or with profile matching provided will be instantiated. This is a very powerful mechanism.
#Profile("prd")
public class PersonManagerServiceImpl implements PersonManagerService
//...
#Profile("test")
public class PersonManagerServiceMock implements PersonManagerService
//...
#ContextConfiguration
#ActiveProfiles(value = "test")
public class Test {
use primary or #Primary - if you are autowiring otherService in PersonManagerServiceImpl you can define a second mock bean with primary="true" attribute or #Primary annotation. Spring will prefer primary beans when autowiring.
unwrap transactional proxy (see: Is it possible to unproxy a Spring bean? and Mocking a property of a CGLIB proxied service not working) to access setter. A bit hacky, but works for others
Related
I am writing a small CRUD in Spring and Java. And I want to use a separate file for writing logic, this is very convenient for me, I did this when developing with NestJS. I have a few questions, is it correct to do this in Spring, or should I do everything inside a function in the controller. And if I write logic in a separate file, I should mark the logic class as #Component and the functions inside it as #Bean, right? I am new to Spring and as I understand it, I have to do this in order for the application to work correctly and my functions to be in the application context.
AuthLogic.java
#Component
public class AuthLogic {
#Bean
public void register() {
// code ...
}
}
AuthController.java
#RestController
public class AuthController {
#RequestMapping(value = "/register", method = RequestMethod.POST)
#ResponseStatus(HttpStatus.CREATED)
public void register(#Valid #RequestBody UserDTO newUser) {
// here I call the register function from AuthLogic
}
}
you can mark your logic class with #Service and use that for example you can make a AuthService and use it like
#Service
public class AuthService{
public returnType login(){
//Logic
}
}
and use this like
#RestController
public class AuthController {
AuthService authService;
#RequestMapping(value = "/register", method = RequestMethod.POST)
#ResponseStatus(HttpStatus.CREATED)
public void register(#Valid #RequestBody UserDTO newUser) {
authService.login();
}
}
You can write your business logic in a new separate file at service layer.
Suppose you name it as AuthService and you mark it with annotation #Service.
#Service
public class AuthService{
}
You can then Autowire it in your controller class.
#RestController
public class AuthController {
#Autowired
AuthService authService;
#RequestMapping(value = "/register", method = RequestMethod.POST)
#ResponseStatus(HttpStatus.CREATED)
public void register(#Valid #RequestBody UserDTO newUser) {
// here I call the register function from AuthLogic
}
}
Using separate files, or classes more importantly, is very recommended in Spring, and I assume most other languages.
The #Bean annotation on AuthLogic.java is unneeded and I think may cause startup or compilation errors.
I would change the name of AuthLogic to AuthLogicImpl, create an interface named AuthLogic with the method signature void register(), and have AuthLogicImpl implement AuthLogic. Then you can create a constructor for AuthController which accepts and AuthLogic parameter and sets it to a private field (note using the interface not the implementation in the constructor).
At the core of Spring is the IoC container. This container holds "beans" that can be injected or autowired into other beans. These beans are an instance of their class and can be used by other beans. Remember Spring uses the singleton pattern, so your beans should be stateless. This allows Spring to handle the application startup for you, so you don't need to write a ton of code creating all the different services/classes and wiring them together, it's all automagically done for you.
There are two key annoitations that you appear to be confused about:
#Component Putting this above a class will create an instance of that class (a bean) and put it into the IoC container. Other beans can access this by accepting the original beans interface in its constructor. So if I put #Component above my class FooImpl which implements Foo, then I can create a class, BarImpl with the constructor public BarImpl(Foo foo) {this.foo = foo} and BarImpl can use any public method of Foo (which will use FooImpl's implementation).
#Bean this is to be put on a method of a class that is annotated with #Configuration. This tells Spring that this method should be run at startup, and this method will return a bean that Spring should add to the IoC container. This is a popular way of configuring a bean that requires some parameters, such as the bean that manages the connection to a third party service or datastore, especially when that there is a little bit of logic that needs to go into creating the bean.
Note that the above is very broad, and there are some specifics if you need to dig deep into the spring framework, so there will be more clarification in the Spring documentation or you dig into some established Spring project. However it should suffice to answer the broad question of what is going on with #Component and #Bean.
There is no specific layout or code structure for Spring Boot Projects. However, there are some best practices followed by developers that will help us too. You can divide your project into layers like service layer, entity layer, and repository layer.
We use the entity layer to write all model and POJO classes. We annotate them with #Entity.
We use #Repository to indicate that this is a repository interface that is used to do some basic CRUD operations.
Sidenote:- You don't have to write #Repository for classes that implement or interfaces that extends Repository interfaces provided by Spring Boot framework.
We use #Service to say that this is the service class where your all business logic will be present.
We use the controller layer to receive HTTP requests and send back HTTP Responses or views.
You can learn and understand more from here
You can refer to this Image to understand the structure
project structure
I have a Spring Boot Java application and am trying to inject a #Service into a class. I'm using #Autowired but it's not doing it. I successfully do so in other classes, but not this one.
The service class:
#Service
#Transactional
public class TaskService {
...
}
The class where it works is a Vaadin "view" annotated with a Vaadin #Route annotation. I'm assuming there is something going on behind the scenes with the #Route annotation that allows this to work.
#Route("main")
public class TaskListView extends HorizontalLayout {
private final TaskService taskService;
public TaskListView(#Autowired TaskService taskService) {
this.taskService = taskService;
}
...
}
The class where it does not work is also a Vaadin "view", but does not have a #Route annotation, because it is not intended to be navigable to, but rather used as a sub-component of a view (i.e. would be directly instantiated inside a parent view).
public class EditNotesForm extends VerticalLayout {
#Autowired
private TaskService taskService;
...
}
The first class uses constructor injection, while the second uses property injection. I can't see why this should make a difference, as I have used both techniques successfully in other applications.
From the Vaadin website:
The only difference between using the router in a standard application and a Spring application is that, in Spring, you can use dependency injection in components annotated with #Route. These components are instantiated by Spring and become Spring-initialized beans. In particular, this means you can autowire other Spring-managed beans.
One way to access Spring components from your regular Vaadin components is by creating static get methods to retrieve your Spring components. Here is one way that can be done... but not the only.
#Component
public class StaticHelper {
private static StaticHelper instance;
#Autowired
private ApplicationContext applicationContext;
#PostConstruct
public void registerInstance() {
instance = this;
}
public static <T> T getBean(Class<T> class) {
return instance.applicationContext.getBean(class);
}
}
So in your example...
private TaskService taskService = StaticHelper.getBean(TaskService.class);
Since EditNotesFormdoesn't have the Route annotation, spring can't autodiscover it and therefore it can't inject any dependency.
Since you want to instantiate it manually, you'll need to provide yourself all dependencies.
But if you still want to benefit from automatic dependency injection, take a look at https://www.baeldung.com/spring-beanfactory
I am a beginner to Spring autowire and has seen different type of autowire implementation.
There are 2 common methods as shown below to autowire persistence layer to the service layer.
Which is a better way of autowiring the persistence layer to the service layer?
#Service
public class SomeServiceImpl {
#Autowired
private CustomerDAO customerDAO;
public List<Customer> getAllCustomer() {
return customerDAO.getAllCustomer();
}
}
vs
#Service
public class SomeServiceImpl {
#Autowired
public List<Customer> getAllCustomer(CustomerDAO customerDAO) {
return customerDAO.getAllCustomer();
}
}
None of the above. Although opinionated you shouldn't use field injection (see this and this).
The second one wouldn't even work unless you would be passing the CustomerDAO around yourself.
Instead make the field final and use constructor based injection.
#Service
public class SomeServiceImpl {
private final CustomerDAO customerDAO;
#Autowired
public SomeServiceImpl(CustomerDAO customerDAO) {
this.customerDAO= customerDAO;
}
}
Still easy to test, pass the dao to the constructor and no need to pass it around. Nothing is hidden anymore (less magic) and you still honor OO rules (that an object should be in a valid state after construction).
You could even put a validation inside the constructor to check if the passed in argument isn't null.
In general, The good practice would be to put the #Autowired on a constructor instead of a method. If you put it on a constructor, you can validate that the injected beans are not null and fail fast when you try to start the application and avoid a NullPointerException when you need to actually use the bean.
There are no of advantage with
#Autowired
private CustomerDAO customerDAO;
1) You can use it into whole service class.
2) As explained above if it fail then you will notify on start the application
How to instantiate seesion before unit testing execution so that autowired session in service class creates bean correctly ?
My test uses some methods from a service class. This service class method uses an autowired session. The point is that i don't know how to create/inject into the session in the test (or before it) so that the session bean creates correctly in the service with the details i set beforehand.
The session class looks like this:
#Component
#Scope(value = "session", proxyMode = ScopedProxyMode.TARGET_CLASS)
public class UserSession {
Long idUser;
//...other
//geters and seters
}
Test class:
#RunWith(SpringJUnit4ClassRunner.class)
#SpringApplicationConfiguration(classes = {Application.class})
public class MyTestClass{
#Autowired
private UserSession session;
#Autowired
private MyServiceClass myServiceClass;
#Test
public void myTestMethod() {
....
//This is where i wanted to set some session detailes
//Something like this:
session.setUserRolls(...);
myServiceClass.myServiceMethod();
}
}
In my service class i have something like this:
#Service
public class MyServiceClass{
#Autowired
private UserSession session;
private void myServiceMethod(){
....
List <UserRol> rolls = session.getUserRolls();
//in this case i want to retrieve user rolls from session object
//
//now i get an error in my current implementation that looks like this
//Error: no Scope registered for scope name "session"
}
}
The only thing you should do is to put #WebAppConfiguration before your test class:
#RunWith(SpringJUnit4ClassRunner.class)
#SpringApplicationConfiguration(classes = {Application.class})
#WebAppConfiguration
public class MyTestClass{
......
}
Inside the class you should inject your session class using #autowired exactly like you did.
After that inside your test, before you call your service function, you can set your session details using setters. The details will be visible inside your service so everything should work just fine.
The presence of #WebAppConfiguration on your test class instructs the TestContext framework (TCF) that a WebApplicationContext (WAC) should be loaded for your tests, so that will give you session scoped beans.
IMHO trying to autowire a session scoped bean in a unit test is bad design. Normal unit testing should be possible by mocking the bean. With mock framework like mockito, you can even control that methods have been called with the expected parameters.
If you need actual interaction with that bean - but it is now an integration test - you should manually build the bean the way it should look like in the use case you are testing, and manually inject it into the service class you are testing.
Anyway, having dependencies on a session scoped bean (isn't it controller of view layer?) inside a service bean (should be service layer) smells. It may be a perfectly correct design, but you really should think twice about that, mainly if it is now hard to test.
Don't forget: test should remain as simple as possible. If they cannot, look again at your general design.
You can use the Spring MockMVC framework and add a #WebAppConfiguration, that will give you session scoped beans.
Look at this example How to test a spring controller method by using MockMvc?
I have a Spring MVC application using JPA 2. All the controllers are annotated with #Transactional at the class level.
Is it possible to keep that annotation at the class level and simply override it with another #Transactional annotation at the method level? I have one method I'd like to make SERIALIZABLE.
You can add multiple transaction managers by adding qualifiers to distinguish which one that should be used, provided that they have been configured:
#Transactional("global")
public class SomeService {
public void methodThatUsesTheGlobalTxManager() {
// ...
}
#Transactional("special")
public void methodThatUsesTheSpecialTxManager() {
// ...
}
}