Factory injection in Spring
//XML
<bean id="bar" factory-bean="barFactory" factory-method="getInstance"/>
//Java
How do you do dependency injection with only interfaces and factory classes and no configuration classes ？
//Service
public interface MyService {
void doSomething();
}
//ServiceFactory
public class MyServiceFactory {
MyService getInstance() {
//...
}
}
//Controller
#Controller
public class MyController {
#Autowired
private MyService myService;
}
you can do like this without adding the xml coding.
#Configuration
public class MyServiceFactory {
#Bean
MyService myService() {
return new MyService() {
#Override
public void doSomething() {
}
}
}
}
#Controller
public class MyController {
#Autowired
private MyService myService;
public void execute() {
myService.doSomething();
}
}
You can manually ask Spring to Autowire it.
Have your factory implement ApplicationContextAware. Then provide the following implementation in your factory:#Override public void setApplicationContext(final ApplicationContext applicationContext) { this.applicationContext = applicationContext; }
and then do the following after creating your bean:
YourBean bean = new YourBean();
applicationContext.getAutowireCapableBeanFactory().autowireBean(bean);
bean.init(); //If it has an init() method.
Related
when i am using #autowire to inject my dependencies in Configuration
class its giving me as null please refer the code below .
#Configuration
public class DataSourceConfig {
#Autowired
AppService appService;
#Bean
public BeanDefinitionRegistryPostProcessor beanPostProcessor() {
return new BeanDefinitionRegistryPostProcessor() {
public void postProcessBeanFactory(ConfigurableListableBeanFactory arg0) throws BeansException {
}
public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry beanRegistry) throws BeansException {
createBeans(beanRegistry);
}
};
}
private void createBeans(BeanDefinitionRegistry beanRegistry,DataSourceConfigService ds) {
appService.getDbDetails();
appService is null here if i will call it using this way
BeanDefinitionRegistryPostProcessor beanPostProcessor(AppService
appService) then in AppServiceImpl class AppDao dependency will be null
}
}
//// Service
#Service
public class AppServiceImpl implements AppService{
#Autowired
AppDao ds;
#Override
public List<A> getDatabaseConfiguration() {
return ds.getDbDetails(); // here ds is null
}
}
//dao
#Repository
public class AppDaoImpl implements AppDao {
#Qualifier("nameParamJdbcTemplate")
#Autowired
public NamedParameterJdbcTemplate nameParamJdbcTemplate;
#Override
public List<A> getDbDetails() {
return nameParamJdbcTemplate.query(SELECT_QUERY, new DataSourceMapper()); // nameParamJdbcTemplate is null
}
// datasource config
#Configuration
public class DataSourceBuilderConfig {
#Bean(name = "dbSource")
#ConfigurationProperties(prefix = "datasource")
#Primary
public DataSource dataSource1() {
return DataSourceBuilder.create().build();
}
#Bean(name = "nameParamJdbcTemplate")
#DependsOn("dbSource")
#Autowired
public NamedParameterJdbcTemplate jdbcTemplate1(#Qualifier("dbSource") DataSource dbSource) {
return new NamedParameterJdbcTemplate(dbSource);
}
}
What i want is when ever my beanPostProcessor()
is executed i want all my dependent beans should be instantiated ie
#Autowired
AppService appService;
#Autowired
AppDao ds;
#Qualifier("nameParamJdbcTemplate")
#Autowired
public NamedParameterJdbcTemplate nameParamJdbcTemplate;
I am new to spring so any help or working examples would be great. Thanks
It is null because this #Configuration class also defines a BeanDefinitionRegistryPostProcessor that forces the context to create that bean very early on.
Because you are using field injection, the context has to resolve AppService bean but it can't yet because the post-processor have to be applied first.
Your configuration looks very complex so you may want to simplify it a bit:
Separate low-level infrastructure configuration from main configuration
Always define such post processor as public static method so that the context can invoke the #Bean method without having to construct the class first.
Using the following configuration for #Async methods :
#Configuration
#EnableAsync
public class AsyncConfig implements AsyncConfigurer {
#Override
public Executor getAsyncExecutor() {
//Just to experiment
return new SimpleAsyncTaskExecutor();
}
#Override
public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
return new CustomAsyncExceptionHandler();
}
}
Is there a way to "get" the ability to autowire (or similar) Services ?
I'd like to use such Services to record errors in database and use common services.
Non working sample :
#Component //seems pointless
public class CustomAsyncExceptionHandler extends ServiceCommons implements AsyncUncaughtExceptionHandler {
protected Logger LOG = LoggerFactory.getLogger(this.getClass());
#Autowired
private MyService myService; //always null
#Override
public void handleUncaughtException(Throwable throwable, Method method, Object... obj) {
//null pointer !
myService.doSomething(throwable);
}
}
When using not in #Async methods, #ControllerAdvice global exception handler allows #Autowired fields. Why not in this case ? Is this because of async thread management ?
I just faced this problem and solved this way:
#Configuration
#EnableAsync
public class MyAsyncConfigurer implements AsyncConfigurer {
private CustomAsyncExceptionHandler customAsyncExceptionHandler;
//...
//other code here
//...
#Autowired
public void setCustomAsyncExceptionHandler(CustomAsyncExceptionHandler customAsyncExceptionHandler) {
this.customAsyncExceptionHandler = customAsyncExceptionHandler;
}
#Override
public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
return this.customAsyncExceptionHandler;
}
}
Custom async exception handler annotated with #Component:
#Component
public class CustomAsyncExceptionHandler implements AsyncUncaughtExceptionHandler {
private MyMailService myMailService;
#Autowired
public void setMyMailService(MyMailService myMailService) {
this.myMailService= myMailService;
}
#Override
public void handleUncaughtException(Throwable throwable, Method method, Object... obj) {
myMailService.sendMailToAdmin(throwable, method.getName());
}
}
IoC injects both, myMailService and customAsyncExceptionHandler, correctly whith no errors.
I don't think my solution is the most elegant, but tell me what you think. the idea is to bypass the automatic injection mechanism by using ApplicationContextAware interface. My first attempt was to make my AsyncUncaughtExceptionHandler implementing class to also implement ACAware. But that didn't work. Somehow this class, even annotated as Component or Service seems to live a bit outside the Spring environment. So I did this:
#Configuration
#EnableAsync
public class DemoAsyncConfigurer implements AsyncConfigurer, ApplicationContextAware {
private ApplicationContext applicationContext;
And in the same class:
#Override
public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
DemoAsyncExceptionHandler demoHandler = new DemoAsyncExceptionHandler(); // you can't add the parameter in this constructor, for some reason...
demoHandler.setApplicationContext(applicationContext);
return demoHandler;
}
/**
*
* {#inheritDoc}
*/
#Override
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}
My DemoAsyncExceptionHandler has the following:
private ApplicationContext applicationContext;
public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
this.applicationContext = applicationContext;
}
public void handleUncaughtException(Throwable throwable, Method method, Object... params) {
UserService userService = this.applicationContext.getBean("userService", UserService.class);
// call userService method
That worked! Hope I have helped
I can autowire a list of service beans in spring boot but I need a way to pick the one I need using the name they have given.
#Service("myService")
public class DefaultService implements MyService {
}
#Service("myService2")
public class DefaultService2 implements MyService {
}
#Autowire
List<MyService> services;
is it possible to get DefaultService2 and DefaultService separately from the list.
If you want to get your services by name , implement the pattern factory as below:
Your service implementations :
public interface MyService {
void sayHello();
}
public class DefaultService implements MyService {
private static Logger log = LoggerFactory.getLogger(DefaultService.class);
#Override
public void sayHello() {
log.info("Hello from DefaultService");
}
}
public class DefaultService2 implements MyService {
private static Logger log = LoggerFactory.getLogger(DefaultService2.class);
#Override
public void sayHello() {
log.info("Hello from DefaultService2");
}
}
The factory interface :
public interface MyServiceFactory {
public MyService getMyServiceByName(String name);
}
The factory beans :
#Configuration
public class MyServiceFactoryBean {
#Bean
public FactoryBean serviceLocatorFactoryBean(){
ServiceLocatorFactoryBean factoryBean = new ServiceLocatorFactoryBean();
factoryBean.setServiceLocatorInterface(MyServiceFactory.class);
return factoryBean;
}
#Bean("myService")
#Scope(scopeName = ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public DefaultService defaultService(){
return new DefaultService();
}
#Bean("myService2")
#Scope(scopeName = ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public DefaultService2 defaultService2(){
return new DefaultService2();
}
}
Usage :
#Autowired
MyServiceFactory myServiceFactory;
#Override
public void run(String... strings) throws Exception {
myServiceFactory.getMyServiceByName("myService").sayHello();
myServiceFactory.getMyServiceByName("myService2").sayHello();
}
Results :
2017-08-11 11:32:31.126 INFO 12827 --- [ restartedMain] c.m.test.DefaultService : Hello from DefaultService
2017-08-11 11:32:31.129 INFO 12827 --- [ restartedMain] c.m.test.DefaultService2 : Hello from DefaultService2
Add #Qualifier annotation:
#Autowired
#Qualifier("myService")
MyService myService;
Just a guess, but have you tried this?:
#Autowire
MyService myService;
#Autowire
MyService myService2;
The field name should be hint enough to Spring. Otherwise use #Qualifier as explained by albert_nil.
You can use :
#Autowired
#Qualifier("myService")
MyService myService;
Or use resource annotation. It should work.
#Resource
MyService myService;
#Resource
MyService myService2;
Try to iterate your bean in the List and identify each bean using reflection api .getClass().getSimpleName(). This will return the String name of your class.
for(MyService service : services) {
if(service.getClass().getSimpleName().equals("DefaultService")) {
MyService defaultService = service; // This is DefaultService class
}
if(service.getClass().getSimpleName().equals("DefaultService2")) {
MyService defaultService2 = service; // This is DefaultService2 class
}
}
With this, you will know what would be the Service you are using.
i can take out the beans seperately by sorting autowire order.naming is not needed now.
#Order(value=1)
#Service
public class DefaultService implements MyService {
}
#Service
#Order(value=2)
public class DefaultService2 implements MyService {
}
I'm doing unit test using spring mvc test framework.
The following is my source code:
com.exmple.main
MyController.java
#Controller
public class MyController {
#Autowired
private MyService myService;
#RequestMapping(method = RequestMethod.POST)
#ResponseBody
public Map<Object, Object> myControllerFunction(#RequestBody final Object jsonRequest) {
/* do something */
return response;
}
}
MyRepository.java
#Repository
public interface MyRepository extends JpaRepository<My, String> {
#Query(value="select * from my d where (d.start_date<to_date(:date,'YYYY/DD/MM')) and (d.end_date>to_date(:date,'YYYY/DD/MM'))", nativeQuery=true)
List<My> findByDate(#Param("date") String date);
}
MyService.java
public interface MyService {
List<My> findByDate(String date);
}
MyServiceImpl.java
#Service
public class MyServiceImpl implements MyService {
#Autowired
MyRepository destRepo;
#Override
public List<My> findByDate(String date) {
List<My> listDest = destRepo.findByDate(date);
return listDest;
}
}
com.example.test
MyControllerTest.java
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes={TestConfig.class})
#WebAppConfiguration
public class MyControllerTest {
private MockMvc mockMvc;
#Autowired
MyService myService;
#Autowired
protected WebApplicationContext webApplicationContext;
#Before
public void setup() throws Exception {
// this.mockMvc = MockMvcBuilders.standaloneSetup(controller).build();
mockMvc = MockMvcBuilders.webAppContextSetup(webApplicationContext).build();
}
#Test
public void listAllMy() throws Exception {
}
}
TestConfig.java
#Configuration
public class TestConfig {
#Bean
public MyService myService() {
// set properties, etc.
return new MyServiceImpl();
}
}
When I run test, the following error is displayed
nested exception is org.springframework.beans.factory.NoSuchBeanDefinitionException
I know the exception occurred because MyService didn't find any bean of MyRepository.
But I don't know how to create a bean of repository.
Please teach me how to create a bean of repository class using Java (not xml).
You need to enable the JPA repositories in your config class, specify the package that contains the repositories as below
#Configuration
#EnableJpaRepositories(basePackages = {
"com.example.repository"
})
public class TestConfig {
#Bean
public MyService myService() {
// set properties, etc.
return new DestinationServiceImpl();
}
}
Edit: looks like you haven't defined entityManager, and dataSource. Refer to a tutorial here and also answer to similar question here
I would like some of my beans know something about test. SOMETHING. May be test class name or some of it's methods.
For example, suppose my test class has a method
public String getTestName() {
return getClass().getSimpleName();
}
This method returns test name and can be overridden.
Is it possible to inject this name into some beans of Spring context, to use during test?
For example, with autowire feature:
#Autowired
public String testName;
not only in test class, but in other beans too.
UPDATE
Below are two (failed) attempts to implement injecting testInstance. May be there are some convenient ways to do that?
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = TestClassAwareTry._Config.class)
#TestExecutionListeners(value = { TestClassAwareTry._Listener.class },
mergeMode = TestExecutionListeners.MergeMode.MERGE_WITH_DEFAULTS)
public class TestClassAwareTry {
/**
* Interface to tag beans, who want to know if they are in test
*/
public interface TestInstanceAware {
void setTestInstance(Object value);
}
/**
* Sample bean, which would like to know if it is in test
*/
public static class MyBean implements TestInstanceAware {
private Object testInstance;
{
System.out.println("MyBean constructed");
}
public void setTestInstance(Object value) {
this.testInstance = value;
System.out.println("testInstance set");
}
public Object getTestInstance() {
return testInstance;
}
}
/**
* Attempt to inject testInstance with a bean, implementing {#link BeanPostProcessor}
*/
public static class TestInstanceInjector implements BeanPostProcessor {
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
if( bean instanceof TestInstanceAware ) {
TestInstanceAware aware = (TestInstanceAware) bean;
// we don't have access to test instance here
// otherwise I would write
//Object testInstance = getTestInstance();
//aware.setTestInstance(testInstance);
}
return bean;
}
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
return bean;
}
}
/**
* Attempt to inject testInstance with test execution listener
*/
public static class _Listener extends AbstractTestExecutionListener {
#Override
public void prepareTestInstance(TestContext testContext) throws Exception {
Object testInstance = testContext.getTestInstance();
ApplicationContext context = testContext.getApplicationContext();
// we don't have setBean() method
// I would write if I have
// context.setBean("testInstance", context);
}
}
/**
* Java-based configuration
*/
#Configuration
public class _Config {
#Bean
public MyBean myBean() {
return new MyBean();
}
#Bean
public TestInstanceInjector testInstanceInjector() {
return new TestInstanceInjector();
// I would acquire test instance here and pass it to constructor, if I can
}
}
#Autowired
public MyBean myBean;
#Test
public void testInjected() {
assertSame( this, myBean.getTestInstance());
}
}
I've ended up creating ContextCustomizerFactory that registers BeanPostProcessor
package com.company.testing.base.spring;
import java.util.List;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
import org.springframework.test.context.ContextConfigurationAttributes;
import org.springframework.test.context.ContextCustomizer;
import org.springframework.test.context.ContextCustomizerFactory;
public class TestAwareContextCustomizerFactory implements ContextCustomizerFactory {
#Override
public ContextCustomizer createContextCustomizer(
Class<?> testClass, List<ContextConfigurationAttributes> configAttributes) {
return (context, mergedConfig) -> {
ConfigurableListableBeanFactory beanFactory = context.getBeanFactory();
beanFactory.addBeanPostProcessor(
new TestInstanceAwareBeanPostProcessor(mergedConfig.getTestClass()));
};
}
}
TestInstanceAwareBeanPostProcessor
public class TestInstanceAwareBeanPostProcessor implements BeanPostProcessor {
private final Class<?> testClass;
TestInstanceAwareBeanPostProcessor(Class<?> testClass) {
this.testClass = testClass;
}
#Override
public Object postProcessBeforeInitialization(Object bean, String beanName)
throws BeansException {
if (bean instanceof TestClassAware) {
((TestClassAware) bean).setTestClass(testClass);
}
return bean;
}
#Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
return bean;
}
}
resources/META-INF/spring.factories
# ContextCustomizerFactories for the Spring TestContext Framework
org.springframework.test.context.ContextCustomizerFactory = \
com.company.testing.base.spring.TestAwareContextCustomizerFactory
The only way I've been able to do this is by delaying creation of the subject until you are in the test method and to have the bean in the prototype scope.
#RunWith(SpringJUnit4ClassRunner.class)
#ContextConfiguration(classes = { LiveConfig.class, DevConfig.class})
#ActiveProfiles("Dev")
public class MeTest {
#Autowired
public ApplicationContext context;
#Autowired
DevConfig devConfig;
#Rule
public TestName nameRule = new TestName();
#Before
public void setName() {
devConfig.setSettings(nameRule.getMethodName());
}
#Test
public void test() {
Bean subject = context.getBean(Bean.class);
System.out.println(subject.settings);
assertThat(subject.settings, is(nameRule.getMethodName()));
}
#Test
public void test2() {
Bean subject = context.getBean(Bean.class);
System.out.println(subject.settings);
assertThat(subject.settings, is(nameRule.getMethodName()));
}
}
#Configuration
class LiveConfig {
#org.springframework.context.annotation.Bean
public String getSettings() {
return "/some/real/file.txt";
}
#org.springframework.context.annotation.Bean
#Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public Bean getBean() {
return new Bean();
}
}
#Configuration
class DevConfig {
private String settings;
#org.springframework.context.annotation.Bean
#Profile("Dev")
#Scope(value = ConfigurableBeanFactory.SCOPE_PROTOTYPE)
public String getSettings() {
return settings;
}
public void setSettings(String settings) {
this.settings = settings;
}
}
class Bean {
public Bean() {
System.out.println("Bean");
}
String settings;
#Autowired
void setSettings(String settings) {
System.out.println("Settings: " + settings);
this.settings = settings;
}
}
This uses Profiles to change what Live sees and what the tests see, and the a NameRule to get the name. It is clunky.
I would NOT use the TestName rule, but rather the TemporaryFolder rule and use that to set whatever setting your application uses for the output folder. I'd also only use DI in a test in very rare cases (i.e. full blown integration tests).
Do you mean like this?
public class MyTest {
#Test
public void testName() {
MyBean b = new MyBean(MyTest.class.getSimpleName());
b.doSomething();
}
}
You can achieve this in a more elegant way using Spring Boot Auto configuration feature by making yours, this way:
define a Configuration class that exposes or registers your bean this way:
#Configuration
public class MyBeanProviderConfiguration {
#ConditionalOnMissingBean
#Bean
public MyBean myBean() {
// return a fully initialised MyBean instance
}
}
Then define a custom annotation Spring Boot like, say #AutoConfigureMyBean this way:
#Retention(RetentionPolicy.RUNTIME)
#Target(ElementType.TYPE)
#ImportAutoConfiguration(MyBeanProviderConfiguration.class)
public #interface AutoConfigureMyBean {}
Then you can use this in your Spring test, here is an example:
#RunWith(SpringRunner.class)
#AutoConfigureMyBean
public class MyTest {
#Autowired
MyBean myBean;
}
Or also declare your MyBean #Autowired dependent bean in a regular Spring test (using a Config class), A MyBean instance will be automatically injected into it.