Creating an object of an #Service bean, is it possible? - java

i have an restful application with all the #Service,#RestController,#Repository beans. and im autowiring required beans.
Now i want to use the #service class in another class that is not managed by spring, is that possible?
These 2 classes are also in 2 diffrent maven projects if that makes any diffrence
i have tried creating a new object , as expected to no awail.
i have also tried creating diffrent constructors also to no awail.
i have googled for some anwsers but havent found any so now i turn to you experts ;)
The class i want to use!
#Service
public class ProductService {
ProductRepository repository;
#Autowired
public ProductService(ProductRepository repository){
this.repository = repository;
}
}
the Restcontroller
#RestController
#RequestMapping(path = "/product")
public class ProductResource {
#Autowired
ProductService service;
}
Repo
public interface ProductRepository extends JpaRepository<Product,Long> {
}
Here is where i want to create the service.
public static void main(String[] args) {
String chromeDriver = args[0];
String method = args[1];
String domainName = args[2];
ProductService service = new ProductService();
System.setProperty("webdriver.chrome.driver", chromeDriver);
Runner runner = new Runner(method,domainName);
runner.run();
}

As far as I know, you can instantiate a Spring-managed class in a non-Spring-managed class as long as the Spring-managed class (in this case the service) doesn't contain any Spring dependencies in it, as those will remain null (non initialized) because they are never gonna be injected by Spring.
Your service looks good to me because the ProductRepository field is not #autowired, but in your code you're creating the ProductService like this:
ProductService service = new ProductService();
While this parameterless constructor doesn't exist in the ProductService class:
#Service
public class ProductService
{
ProductRepository repository;
#Autowired
public ProductService(ProductRepository repository)
{
this.repository = repository;
}
}

I think this is not possible (I mean, it technically is, but it is not going to work).
To have access to your service class your second application needs to have access to the same Spring Context.
This is because Spring Context in your base application defines necessary dependencies that your second application doesn't have access to. One of the examples for this is ProductRepository repository (which is a way Spring Boot app will talk with the database), have no Spring Context and thus information on DB location and connection URL.
In your case you need to replicate the class and mechanism to connect to DB with DB configuration in your second project.

There's a workaround to "inject" dependencies manually. Create a managed component that stores the reference to the ApplicationContext in a static variable, so that you can access from non-managed classes:
#Component
public class ApplicationContextProvider implements ApplicationContextAware {
private static ApplicationContext applicationContext;
public static ApplicationContext applicationContext() {
return applicationContext;
}
#Override
public void setApplicationContext(ApplicationContext applicationContext) {
ApplicationContextProvider.applicationContext = applicationContext;
}
}
public class NoManagedClass {
private final ManagedClass bean;
public NoManagedClass() {
this.bean = ApplicationContextProvider.applicationContext().getBean(ManagedClass.class);
}
}
However, be aware that your non-managed objects should be created after the application context is set. You still have to start your Spring application in the main method so that the beans are initialized.

Related

Spring dependency injection with constructor arguments

I have spring boot, hibernate application and android application for client side. Also I am using java.net.Socket api for socket connection.
Before I was creating server socket like this new Server(12346); and everything was good enough. But now I need access to database from socket class e.g. with #Autowired UsersDao field, but of course it is null because Socket class is not visible by Spring Framework.
So how do I make dependency injection on Socket class using port as constructor argument and make UserDao non-null?
You can access the Spring Application Context from static method and use this static method to load your repository bean in your Server class instead of autowiring it.
You need to create the following classes (found here):
ApplicationContextProvider
#Component
public class ApplicationContextProvider implements ApplicationContextAware {
private static ApplicationContext context;
public ApplicationContext getApplicationContext() {
return context;
}
#Override
public void setApplicationContext(ApplicationContext ctx) {
context = ctx;
}
}
SpringConfiguration
#Configuration
public class SpringConfiguration {
#Bean
public static ApplicationContextProvider contextProvider() {
return new ApplicationContextProvider();
}
}
And then your non-Spring managed Server class:
public class Server {
//your code
public void doUsersDaoStuff() {
UsersDao usersDao = (UsersDao) SpringConfiguration.contextProvider().getApplicationContext().getBean("UsersDao");
// Do your own stuff with UsersDao here...
}
}

How to get bean using application context in spring boot

I am developing a SpringBoot project and I want to get the bean by its name using applicationContext. I have tried many solution from web but could not succeed. My Requirement is that I have a controller
ControllerA
and inside the controller I have a method getBean(String className). I want to get instance of registered bean. I have hibernate entities and I want to get an instance of the bean by passing the name of class only in getBean method.
Please help if someone know the solution.
You can Autowire the ApplicationContext, either as a field
#Autowired
private ApplicationContext context;
or a method
#Autowired
public void context(ApplicationContext context) { this.context = context; }
Finally use
context.getBean(SomeClass.class)
You can use ApplicationContextAware.
ApplicationContextAware:
Interface to be implemented by any object that wishes to be notified
of the ApplicationContext that it runs in. Implementing this interface
makes sense for example when an object requires access to a set of
collaborating beans.
There are a few methods for obtaining a reference to the application context. You can implement ApplicationContextAware as in the following example:
package hello;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
#Component
public class ApplicationContextProvider implements ApplicationContextAware {
private ApplicationContext applicationContext;
#Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}
public ApplicationContext getContext() {
return applicationContext;
}
}
Update:
When Spring instantiates beans, it looks for ApplicationContextAware implementations, If they are found, the setApplicationContext() methods will be invoked.
In this way, Spring is setting current applicationcontext.
Code snippet from Spring's source code:
private void invokeAwareInterfaces(Object bean) {
.....
.....
if (bean instanceof ApplicationContextAware) {
((ApplicationContextAware)bean).setApplicationContext(this.applicationContext);
}
}
Once you get the reference to Application context, you get fetch the bean whichever you want by using getBean().
actually you want to get the object from the Spring engine, where the engine already maintaining the object of your required class at that starting of the spring application(Initialization of the Spring engine).Now the thing is you just have to get that object to a reference.
in a service class
#Autowired
private ApplicationContext context;
SomeClass sc = (SomeClass)context.getBean(SomeClass.class);
now in the reference of the sc you are having the object.
Hope explained well. If any doubt please let me know.
Even after adding #Autowire if your class is not a RestController or Configuration Class, the applicationContext object was coming as null. Tried Creating new class with below and it is working fine:
#Component
public class SpringContext implements ApplicationContextAware{
private static ApplicationContext applicationContext;
#Override
public void setApplicationContext(ApplicationContext applicationContext) throws
BeansException {
this.applicationContext=applicationContext;
}
}
you can then implement a getter method in the same class as per your need to get the bean. Like:
applicationContext.getBean(String serviceName,Interface.Class)
Using SpringApplication.run(Class<?> primarySource, String... arg) worked for me. E.g.:
#SpringBootApplication
public class YourApplication {
public static void main(String[] args) {
ConfigurableApplicationContext context = SpringApplication.run(YourApplication.class, args);
}
}
As an alternative approach you can use ConfigurableApplicationContext to get bean of any class which is annotated with #Component, #Repository or #Service.
Let's say you want to get a bean of the class BaseComponent :
#Service
public class BaseComponent {
public String getMessage() {
return "hello world";
}
}
Now you can use ConfigurableApplicationContext to get the bean:
#Component
public class DemoComponent {
#Autowired
ConfigurableApplicationContext applicationContext;
public BaseComponent getBeanOfBaseComponent() {
return applicationContext.getBean(BaseComponent.class);
}
}
You can use the ApplicationContextAware class that can provide the application context.
public class ApplicationContextProvider implements ApplicationContextAware {
private static ApplicationContext ctx = null;
public static ApplicationContext getApplicationContext() {
return ctx;
}
#Override
public void setApplicationContext(final ApplicationContext ctx) throws BeansException {
ApplicationContextProvider.ctx = ctx;
}
/**
* Tries to autowire the specified instance of the class if one of the specified
* beans which need to be autowired are null.
*
* #param classToAutowire the instance of the class which holds #Autowire
* annotations
* #param beansToAutowireInClass the beans which have the #Autowire annotation
* in the specified {#classToAutowire}
*/
public static void autowire(Object classToAutowire, Object... beansToAutowireInClass) {
for (Object bean : beansToAutowireInClass) {
if (bean == null) {
ctx.getAutowireCapableBeanFactory().autowireBean(classToAutowire);
}
}
}
}
If you are inside of Spring bean (in this case #Controller bean) you shouldn't use Spring context instance at all. Just autowire className bean directly.
BTW, avoid using field injection as it's considered as bad practice.
One API method I use when I'm not sure what the bean name is org.springframework.beans.factory.ListableBeanFactory#getBeanNamesForType(java.lang.Class<?>). I simple pass it the class type and it retrieves a list of beans for me. You can be as specific or general as you'd like to retrieve all the beans associated with that type and its subtypes, example
#Autowired
ApplicationContext ctx
...
SomeController controller = ctx.getBeanNamesForType(SomeController)
Easy way in configration class call the BEAN annoted method . Yes u heard it right---- :P calling SpringBoot #Bean annoted method return the same bean from config .I was trying to call a logout in #predestroy method in config class from a bean and direcltly called the method to get the same bean .
P.S. : I added debug in the #bean annotated method but it didn't entered the method even when i called it.Sure to blame -----> Spring Magic <----
You can use ServiceLocatorFactoryBean. First you need to create an interface for your class
public interface YourClassFactory {
YourClass getClassByName(String name);
}
Then you have to create a config file for ServiceLocatorBean
#Configuration
#Component
public class ServiceLocatorFactoryBeanConfig {
#Bean
public ServiceLocatorFactoryBean serviceLocatorBean(){
ServiceLocatorFactoryBean bean = new ServiceLocatorFactoryBean();
bean.setServiceLocatorInterface(YourClassFactory.class);
return bean;
}
}
Now you can find your class by name like that
#Autowired
private YourClassfactory factory;
YourClass getYourClass(String name){
return factory.getClassByName(name);
}
Just use:
org.springframework.beans.factory.BeanFactory#getBean(java.lang.Class)
Example:
#Component
public class Example {
#Autowired
private ApplicationContext context;
public MyService getMyServiceBean() {
return context.getBean(MyService.class);
}
// your code uses getMyServiceBean()
}

Spring Boot Autowired null

I have several classes in a Spring Boot project, some work with #Autowired, some do not. Here my code follows:
Application.java (#Autowired works):
package com.example.myproject;
#ComponentScan(basePackages = {"com.example.myproject"})
#Configuration
#EnableAutoConfiguration
#EnableJpaRepositories(basePackages = "com.example.myproject.repository")
#PropertySource({"classpath:db.properties", "classpath:soap.properties"})
public class Application {
#Autowired
private Environment environment;
public static void main(String[] args) {
SpringApplication.run(Application.class);
}
#Bean
public SOAPConfiguration soapConfiguration() {
SOAPConfiguration SOAPConfiguration = new SOAPConfiguration();
SOAPConfiguration.setUsername(environment.getProperty("SOAP.username"));
SOAPConfiguration.setPassword(environment.getProperty("SOAP.password"));
SOAPConfiguration.setUrl(environment.getProperty("SOAP.root"));
return SOAPConfiguration;
}
HomeController (#Autowired works):
package com.example.myproject.controller;
#Controller
class HomeController {
#Resource
MyRepository myRepository;
MyService (#Autowired does not work):
package com.example.myproject.service;
#Service
public class MyServiceImpl implements MyService {
#Autowired
public SOAPConfiguration soapConfiguration; // is null
private void init() {
log = LogFactory.getLog(MyServiceImpl.class);
log.info("starting init, soapConfiguration: " + soapConfiguration);
url = soapConfiguration.getUrl(); // booom -> NullPointerException
I do not get the SOAPConfiguration but my application breaks with a null pointer exception when I try to access it.
I have already read many Threads here and googled around, but did not find a solution yet. I tried to deliver all necessary information, please let me know if anything misses.
I guess you call init() before the autowiring takes place. Annotate init() with #PostConstruct to make it call automatically after all the spring autowiring.
EDIT: after seeing your comment, I guess you are creating it using new MyServiceImpl(). This takes away the control of the MyServiceImpl from Spring and gives it to you. Autowiring won't work in those case
Did you created a bean for the class SOAPConfiguration in any of your configuration classes? If you want to autowire a class in your project, you need to create a bean for it. For example,
#Configuration
public class SomeConfiguration{
#Bean
public SOAPConfiguration createSOAPConfiguration(){
return new SOAPConfiguration();
}
}
public class SomeOtherClass{
#Autowired
private SOAPConfiguration soapConfiguration;
}

How to disable Spring autowiring in unit tests for #Configuration/#Bean usage

I want configure a component test using spring-test configuration inner class (#Configuration). Tested components has some services which I'd like to mock for the test. These services are classes (no interface used) and have spring annotations (#Autowired) in them. Mockito can easily mock them, however, I found no way of disabling spring autowiring.
Example how I can easily reproduce:
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = SomeTest.Beans.class)
public class SomeTest {
// configured in component-config.xml, using ThirdPartyService
#Autowired
private TestedBean entryPoint;
#Test
public void test() {
}
#Configuration
#ImportResource("/spring/component-config.xml")
static class Beans {
#Bean
ThirdPartyService createThirdPartyService() {
return mock(ThirdPartyService.class);
}
}
}
public class ThirdPartyService {
#Autowired
Foo bar;
}
public class TestedBean {
#Autowired
private ThirdPartyService service;
}
In this example "TestBean" represents the service to be mocked. I would NOT like "bar" to be injected by spring! #Bean(autowire = NO) does not help (in fact, that's the default value).
(Please save me from "use interfaces!" comments - the mocked service can be 3rd party which I can't do anything with.)
UPDATE
Springockito partially solves the problem, as long as you don't have to have anything else to configure (so you can't use configuration class with Springockito - it does not support it), but use mocks only.
Still looking for pure spring solution, if there's any...
Here is my solution to your problem:
import static org.mockito.Mockito.mockingDetails;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.InstantiationAwareBeanPostProcessorAdapter;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
#Configuration
public class MockitoSkipAutowireConfiguration {
#Bean MockBeanFactory mockBeanFactory() {
return new MockBeanFactory();
}
private static class MockBeanFactory extends InstantiationAwareBeanPostProcessorAdapter {
#Override
public boolean postProcessAfterInstantiation(Object bean, String beanName) throws BeansException {
return !mockingDetails(bean).isMock();
}
}
}
and then just
#Import(MockitoSkipAutowireConfiguration.class)
in your test #Configuration and you are all set
I solved it by creating FactoryBean for my bean instead of just mocking bean. At this way Spring don't try to autowire fields.
Factory bean helping class:
public class MockitoFactoryBean<T> implements FactoryBean<T> {
private final Class<T> clazz;
public MockitoFactoryBean(Class<T> clazz) {
this.clazz = clazz;
}
#Override public T getObject() throws Exception {
return mock(clazz);
}
#Override public Class<T> getObjectType() {
return clazz;
}
#Override public boolean isSingleton() {
return true;
}
}
Actual test context part:
#Configuration
public class TestContext {
#Bean
public FactoryBean<MockingService> mockingService() {
return new MockitoFactoryBean<>(MockingService.class);
}
}
Check Spring profiles. You don't need to disable auto wiring, you need to inject different beans for different configuration.
You could add the mocked service manually to the spring application context via org.springframework.beans.factory.config.SingletonBeanRegistry#registerSingleton. This way the mock is not post-processed by spring and spring does not attempt to autowire the mock. The mock itself will be injected into your tested bean.
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = SomeTest.Beans.class)
public class SomeTest {
// configured in component-config.xml, using ThirdPartyService
#Autowired
private TestedBean entryPoint;
#Autowired
private ThirdPartyService thirdPartyServiceMock;
#Test
public void test() {
}
#Configuration
static class Beans {
#Autowired
private GenericApplicationContext ctx;
#Bean
TestedBean testedBean() {
ctx.getBeanFactory().registerSingleton("thirdPartyService", mock(ThirdPartyService.class));
return new TestedBean();
}
}
public static class ThirdPartyService {
#Autowired
Object bar;
}
public static class TestedBean {
#Autowired
private ThirdPartyService service;
}
}
I am in quite the same situation.
What I found that if you do not set the context loader by #ContextConfiguration annotation on your test class, the default context loader will be used, which derived from AbstractGenericContextLoader. I had a look at its source and turned out it registers all the bean post processors which are responsible for reading annotations such #Autowired. In other words, annotation config is enabled by default.
So the main problem is that there are two configurations which are in conflict: in the java config we said that autowiring is not needed, while the autowired annotation tells the opposite. The real question is how to disable the annotation processing in order to eliminate the undesired configuration.
As far as I know there is no such spring implementation of ContextLoader which would not be derived from AbstractGenericContextLoader so I guess the only we can do is to write our own. It would be something like this:
public static class SimpleContextLoader implements ContextLoader {
#Override
public String[] processLocations(Class<?> type, String... locations) {
return strings;
}
#Override
public ApplicationContext loadContext(String... locations) throws Exception {
// in case of xml configuration
return new ClassPathXmlApplicationContext(strings);
// in case of java configuration (but its name is quite misleading)
// return new AnnotationConfigApplicationContext(TestConfig.class);
}
}
Of course it would be worth to spend more time to find out how to implement ContextLoader properly.
Cheers,
Robert
There are so many ways of doing this, I'm pretty sure that this answer will be incomplete, but here are a few options...
As currently seems to be recommended practice, use constructor injection for your services rather than autowiring the fields directly. This makes testing like this so much easier.
public class SomeTest {
#Mock
private ThirdPartyService mockedBean;
#Before
public void init() {
initMocks(this);
}
#Test
public void test() {
BeanUnderTest bean = new BeanUnderTest(mockedBean);
// ...
}
}
public class BeanUnderTest{
private ThirdPartyService service;
#Autowired
public BeanUnderTest(ThirdPartyService ThirdPartyService) {
this.thirdPartyService = thirdPartyService;
}
}
By doing that, you can also mix up autowired and mocked services by autowiring into the test itself and then constructing the beans under test with the most useful mix of autowired and mocked beans.
A reasonable alternative is to use Spring profiles to define stub services. This is particularly useful when wish to use the same stubbed features in multiple tests:
#Service
#Primary
#Profile("test")
public class MyServiceStub implements MyService {
// ...
}
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = SomeTest.Beans.class)
#ActiveProfiles({"test"})
public class SomeTest {
// ...
}
By using the #Primary annotation, it ensures that this stub bean will be used instead of any other bean implementing the MyService interface. I tend to use this approach for things like email services, where by changing profile, I'm able to switch between a real mail server and Wiser.

Context initialization issue for controller Unit testing with Spring 3.2 and Mockito

I'm trying to provide a clean Unit Test for a Controller of mine. This Controller has a Service as dependency and this Serviceh has a Datasource as dependency.
The test looks like this:
#RunWith(SpringJUnit4ClassRunner.class)
#WebAppConfiguration
#ContextConfiguration
public class ContentActionWebServiceControllerTest {
#Autowired
private WebApplicationContext wac;
private MockMvc mockMvc;
#Autowired
private MyService myService;
#Test
public void getRequestActionList() throws Exception {
when(...)
perform(...);
verify(...);
}
#Configuration
#ImportResource("...")
static class MyTestConfiguration {
#Bean
public MyService myService() {
return Mockito.mock(MyService.class);
}
}
}
And the MyService is something like
#Service
public class MyService {
#Autowired
private MyDataSource myDatasource;
...
}
Because MyService as an Autowired property MyDataSource, the context isn't initialized because it doesn't find any MyDataSource type for satisfying the #Autowired annotation of MyService. But why does it ever try to resolve this annotation? Is this is a mock?
Mockito does use cglib to create a new child class of MyService (and override all methods with mock methods).
But still, the dependencies of the parent will be injected, because this is how Spring does it's job:
if you have a parent class with some #Autowired fields, and a child class that inherits from this parent class, then Spring will inject the #Autowired fields of the parent when instantiating the child. I guess it's the same behavior in your case.
If you use an interface for MyService, then your problem will be solved.
If it's supposed to be a unit test (and not an integration test) you don't even need to use Spring, you can do it all with JUnit+Mockito. Rather than #Autowireing dependencies from Spring context, you can simply create mocks of the support objects (via #Mock) and inject them to the testee (via #InjectMocks). I believe your code could be simplified to something (conceptually) like this:
#RunWith(MockitoJUnitRunner.class)
public class ContentActionWebServiceControllerTest {
#Mock
private Service mockServiceUsedByController;
#InjectMocks
private YourController testee;
#Test
public void getRequestActionList() throws Exception {
assertFalse(testee.getRequestActionList().isEmpty());
// etc.
}
}

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