Im trying to learn Spring but Im having a little trouble using the #Autowired annotation. When I try to run the example below im getting an nullpoint error on classA.hello();line and im not sure why. Any hwlp would be appreciated.
ClassATest
import org.junit.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
#ContextConfiguration(classes = {ContextConfigurationClass.class})
public class ClassATest {
#Autowired
ClassA classA;
#Test
public void test(){
classA.hello();
}
}
ClassA
package com;
import org.springframework.stereotype.Service;
#Service
public class ClassA {
public void hello(){
System.out.println("HELLO");
}
}
Context Configuration
package com;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
#Configuration
#ComponentScan({"com"
})
public class ContextConfigurationClass {
}
The NullPointerException occurs because the test doesn't create a Spring context and therefore doesn't inject ClassA.
To solve this, add #RunWith(SpringRunner.class) to ClassATest.
Related
So I've got a simple spring boot app, #SpringBootApplication, a stub #Configuration and a #RestController all in the same package. Spring-boot-web-starter is there and the webserver comes up fine, actuator endpoints and all. But I cannot for the life of me get the app to pick up the #RestControllers.
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Main.class:
package com.iglossolalia.munin;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class Main {
public static void main(String[] args) {
SpringApplication.run(MuninContext.class, args);
}
}
MuninContext.class:
package com.iglossolalia.munin;
import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
import org.springframework.context.annotation.Configuration;
#Configuration
#EnableAutoConfiguration
public class MuninContext {
}
MuninService.class:
package com.iglossolalia.munin;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
#RestController
public class MuninService {
private static final Logger LOG = LoggerFactory.getLogger(MuninService.class);
public MuninService() {
LOG.info("Started MuninService");
}
#GetMapping("/health")
public String healthCheck() {
return "pong";
}
}
Tried explicitly adding the rest controller to the component scan with no luck there.
You have no #ComponentScan annotation in your MuninContext. Actually you can write SpringApplication.run(Main.class, args) in main method as Spring Initializr generate by default, you don't really need your context, because #SpringBootApplication work as configuration and contains #EnableAutoConfiguration, #ComponentScan, and some other annotations. Otherwise, as you pass your config class as argument in SpringApplication.run method, annotation #SpringBootApplication in Main class has no effect
This is the userService class that requires a bean of type com.example.repository.userRepository that could not be found
package com.example.services;
import javax.transaction.Transactional;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.example.modal.User;
import com.example.repository.userRepository;
#Service
#Transactional
public class UserService {
#Autowired
private userRepository userRepository;
public UserService() {
super();
}
public UserService(userRepository userRepository)
{
this.userRepository = userRepository;
}
public void saveMyuser(User user) {
userRepository.save(user);
}
}
The error message reads :
Consider defining a bean of type 'com.example.repository.userRepository' in your configuration.
This is the repository:
package com.example.repository;
import org.springframework.data.repository.CrudRepository;
import org.springframework.stereotype.Repository;
import com.example.modal.User;
public interface userRepository extends CrudRepository<User,Integer> {
}
this is the application class
package com.example.demo;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.domain.EntityScan;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.data.jpa.repository.config.EnableJpaRepositories;
#SpringBootApplication
public class TutorialProjectApplication {
public static void main(String[] args) {
SpringApplication.run(TutorialProjectApplication.class, args);
}
}
Seems like userRepository interface is outside of spring-boot default scanning i.e. package of that repository interface is not same or sub-package of the class annotated with #SpringBootApplication. If so, you need to add #EnableJpaRepositories("com.example.repository") on your main class.
Update:
After looking at your updated post, you need to add #EnableJpaRepositories("com.example.repository") to TutorialProjectApplication class
Always keep the #SpringBootApplication main class outer package so that it will automatically scan all the subpackages.
In your case you have main class in package com.example.demo; but the repository in package com.example.repository; which are different packages.so spring boot is not able to find the repositories.
So you have to make spring boot aware of the repositories location.
So now you have 2 solutions.
1.Either put repository class in subpackges of Main class package.
2.Or use #EnableJpaRepositories("com.example.repository") in main class.
In your repository you need to annotate the class
#Repository
public interface userRepository extends CrudRepository<User,Integer> {
}
Can you please provide me with an example of primitive type dependency injection in spring boot. I have tried once but TestConfiguration which is my custom bean definition class does not detect or does not recognize by spring boot application.
here is my code,
//Engine class
package com.test2.projectTest;
import org.springframework.stereotype.Component;
#Component
public class Engine {
private String msg;
public String getMsg() {
return msg;
}
public void setMsg(String msg) {
this.msg = msg;
}
}
//Test Configuration
package com.test2.projectTest;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
#Configuration
public class TestConfiguration {
#Bean("engine")
public Engine engine(){
Engine engine = new Engine();
engine.setMsg("Message is injected");
return engine;
}
}
//spring main application
package com.test2.projectTest;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.annotation.ComponentScan;
#SpringBootApplication
public class ProjectTestApplication {
public static void main(String[] args) {
SpringApplication.run(ProjectTestApplication.class, args);
}
}
//JUnit Test
package com.test2.projectTest;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import org.springframework.boot.test.context.TestConfiguration;
import org.springframework.context.ApplicationContext;
import
org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.test.context.junit4.SpringRunner;
#RunWith(SpringRunner.class)
#SpringBootTest
public class ProjectTestApplicationTests {
#Test
public void contextLoads() {
ApplicationContext apc = new
AnnotationConfigApplicationContext(TestConfiguration.class);
Engine e = (Engine) apc.getBean("engine");
e.getMsg();
}
}
// Output - org.springframework.beans.factory.NoSuchBeanDefinitionException:
No bean named 'engine' available
Please suggest any solution to above issue
Add #componentscan annotation in main class and provide engine class package and it should work
#ContextConfiguration(loader = AnnotationConfigContextLoader.class)
#ActiveProfiles(profiles = "test")
#RunWith(MockitoJUnitRunner.class)
public class ConfigurationTest {
#Autowired
private Environment environment;
#Test
public void test1() throws Exception {
environment.getProperty("bhavya",Boolean.class);
}
#Configuration
#Profile("test")
#ComponentScan(basePackages={"com.bhavya.test"})
public static class EnvironmentServiceTestConfiguration{
#Bean
#Primary
public Environment environment(){
return Mockito.mock(Environment.class);
}
}
}
I also tried putting EnvironmentServiceTestConfiguration as a non-inner non-static class, but didn't help.
Here is what I tried in a separate class:
#RunWith(MockitoJUnitRunner.class)
#Profile("test")
#Configuration
class EnvironmentServiceTestConfiguration{
#Bean
#Primary
public Environment environment(){
return Mockito.mock(Environment.class)
}
}
didn't work either
The test class is located in test/java/com.bhavya.test package.
I am trying to run this particular test test1
This is my first test of such kind. I have never before used AnnotationConfigContextLoader.class, enlighten me.
Stacktrace :
java.lang.NullPointerException
at Line number where I have statement :
environment.getProperty("bhavya",Boolean.class);
Try using #RunWith(SpringJUnit4ClassRunner.class)
Here is an example explaining how can be done
https://www.mkyong.com/unittest/junit-spring-integration-example/
Here is a code sample that works for the sample in the question:
package com.example.demo.test;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.mockito.Mockito;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Primary;
import org.springframework.core.env.Environment;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
import org.springframework.test.context.support.AnnotationConfigContextLoader;
import static org.mockito.Matchers.eq;
import static org.mockito.Mockito.when;
#ContextConfiguration(loader = AnnotationConfigContextLoader.class)
#RunWith(SpringJUnit4ClassRunner.class)
public class ConfigurationTest {
#Autowired
private Environment environment;
#Test
public void test1() throws Exception {
System.out.println(environment.getProperty("bhavya",Boolean.class));
}
#Configuration
#ComponentScan(basePackages={"com.example.demo.test"})
public static class EnvironmentServiceTestConfiguration{
#Bean
#Primary
public Environment environment(){
Environment env = Mockito.mock(Environment.class);
when(env.getProperty(eq("bhavya"), eq(Boolean.class))).thenReturn(true);
return env;
}
}
}
Try below annotations for your test class
#ContextConfiguration(classes = Config.class)
#SpringBootTest
#ExtendWith(SpringExtension.class)
#RunWith(SpringJUnit4ClassRunner.class)
I try to use Springs own Dependency Injection in a Junit test case:
import static org.hamcrest.CoreMatchers.equalTo;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;
import org.binarisinformatik.api.AppConfig;
import org.binarisinformatik.satzrechner.SatzRechner;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes=AppConfig.class)
//#SpringApplicationConfiguration(classes = {AppConfig.class})
public class SatzRechnerTest {
#Autowired
private SatzRechner satzRechner; //SUT
#Before
public void setUp() {
// AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(SatzRechnerTest.class);
//satzRechner=context.getBean(SatzRechner.class);
}
#Test
public void addiere_satz_4komma6_zu_zahlwert_10() {
assertThat("Addition von \"4,6\" ergibt nicht 10!",
satzRechner.summe("4,6"), is(equalTo(10)));
}
Im testing a class names SatzRechner in which Spring should also autowire some variables. Here is my Class under test:
#Component
public class SatzRechner {
#Autowired //#Inject
private Rechner taschenRechner;
#Autowired
private Zahlenfabrik zahlenfabrik;
public Integer summe(String zeichenSatz) {
return taschenRechner.summe(zahlenfabrik.erzeugeZahlen(zeichenSatz));
}
}
And AppConfig.class which is using as Configurationfile looks like that:
#Configuration
#ComponentScan(value={"org.binarisinformatik"})
public class AppConfig {
}
What is here the problem?
If you want to use a Spring configuration class, this one must have beans definitions. Please find an example below :
Test class:
import static org.hamcrest.CoreMatchers.equalTo;
import static org.hamcrest.CoreMatchers.is;
import static org.junit.Assert.assertThat;
import org.binarisinformatik.api.AppConfig;
import org.binarisinformatik.satzrechner.SatzRechner;
import org.junit.Before;
import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes=AppConfig.class)
public class SatzRechnerTest {
#Autowired
private SatzRechner satzRechner;
#Test
public void addiere_satz_4komma6_zu_zahlwert_10() {
assertThat("Addition von \"4,6\" ergibt nicht 10!",
satzRechner.summe("4,6"), is(equalTo(10)));
}
}
Configuration class :
You have to declare #Bean annotated methods. These beans are managed by Spring container.
#Configuration
public class AppConfig {
// Beans present here will be injected into the SatzRechnerTest class.
#Bean
public SatzRechner satzRechner() {
return new SatzRechner();
}
#Bean
public Rechner taschenRechner() {
return new TaschenRechner();
}
#Bean
public Zahlenfabrik zahlenfabrik() {
return new Zahlenfabrik();
}
}
Note : I let you properly handle returned types here and beans parameters (if present in your context).
There are two things you have to ensure before you run the test case successfully:
1) Classes SatzRechner, Rechner & Zahlenfabrik should be under "org.binarisinformatik" package
2) Classes Rechner & Zahlenfabrik should also be annotated with #Component as SatzRechner.