Im trying to run a simple spring boot application that just takes a message from kafka and saves in a db2 database.
The problem comes up when im trying to inject my repository in the consumer class!
#Service
#Slf4j
#AllArgsConstructor
public class KafkaConsumer {
private PortalOneRepository portalOneRepository;
private ObjectMapper objectMapper;
#KafkaListener(topics = "topicout")
public void consumeEventHubMessage(String consumerMessage) {
log.info("Received message from kafka queue: {}", consumerMessage);
//Convert string message to java object
try {
DocumentONE[] documentOne = objectMapper.readValue(consumerMessage, DocumentONE[].class);
//Salvar cada mensagem no db2
portalOneRepository.saveAll(Arrays.asList(documentOne));
} catch (JsonProcessingException e) {
log.error("Error receiving message: " + e.getMessage());
}
}
}
And this is my repository:
#Repository
public interface PortalOneRepository extends JpaRepository<DocumentONE, Long> {
}
So after run it shows the following error message:
*************************** APPLICATION FAILED TO START
Description:
Parameter 0 of constructor in
br.examplestream.eventhub.KafkaConsumer required a
bean of type
'br.examplestream.repository.PortalOneRepository'
that could not be found.
Action:
Consider defining a bean of type
'br.examplestream.repository.PortalOneRepository' in
your configuration.
I tried the config solution class but it shows a cyclic dependency injection problem:
> ***************************
APPLICATION FAILED TO START
***************************
Description:
The dependencies of some of the beans in the application context form a cycle:
kafkaConsumer defined in file [Z:\Users\romulo.domingos\IdeaProjects\portal-one-stream\target\classes\br\examplestream\eventhub\KafkaConsumer.class]
┌─────┐
| getPortalOneRepository defined in class path resource [br/examplestream/config/PortalOneConfig.class]
└─────┘
Action:
Relying upon circular references is discouraged and they are prohibited by default. Update your application to remove the dependency cycle between beans. As a last resort, it may be possible to break the cycle automatically by setting spring.main.allow-circular-references to true.
This is the config class that i´ve tried :
#Configuration
public class PortalOneConfig {
private PortalOneRepository portalOneRepository;
#Autowired
ApplicationContext context;
#Bean
public PortalOneRepository getPortalOneRepository(){
return context.getBean(PortalOneRepository.class);
}
}
What is the correct way to inject my repository into my consumer class?
Problem solved.
The problem is caused by a property in application.yml file
autoconfigure: delete:
org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration
After removing the application starts to run normally again.
If I have a bean definition with some configuration within it and I use autowire to get an instance of the same class, is it the instance of the bean definition I get returned or a new instance of the class without any configurations?
class Name {
private fName;
private lName;
constructor(string fName, string lName) {
this.fName = fName;
this.lName = lName;
}
}
#Bean
public Name getName() {
Name test = new Name(thisIsMyFirstName, thisIsMyLastName);
}
--Separate File--
#Autowired
private Name testName;
Is testName here a copy of the #Bean getName() (has thisIsMyFirstName and thisIsMyLastName set) or is it a new instance of the class Name without a first name of thisIsMyFirstName and last name of thisIsMyLastName?
By default, yes, beans are singletons.
But, the Spring framework defines a number of different scopes.
singleton
Scopes a single bean definition to a single object instance per Spring IoC container.
prototype
Scopes a single bean definition to any number of object instances.
request
Scopes a single bean definition to the lifecycle of a single HTTP request; that is each and every HTTP request will have its own instance of a bean created off the back of a single bean definition. Only valid in the context of a web-aware Spring ApplicationContext.
session
Scopes a single bean definition to the lifecycle of a HTTP Session. Only valid in the context of a web-aware Spring ApplicationContext.
global session
Scopes a single bean definition to the lifecycle of a global HTTP Session. Typically only valid when used in a portlet context. Only valid in the context of a web-aware Spring ApplicationContext.
The scope of a bean can be change using the #Scope annotation.
#Bean
#Scope("singleton") // <- singleton is the default. If no #Scope annotation is present, this is what is used.
public BeanA sharedBean() {
// This will only be called once, all subsequent calls will return from the cached reference in the ApplicationContext
return new BeanA();
}
#Bean
#Scope("prototype")
public BeanB privateBean() {
// This will be called every time the bean is injected and a new instance returned.
return new BeanB();
}
This is just another syntax
#Scope(value = ConfigurableBeanFactory.SCOPE_SINGLETON)
Following the advice here, I'm trying to use an embedded Kafka to test my Spring Boot Streams application.
However, simply creating the given configuration
#Configuration
#EnableKafkaStreams
public class StreamsTestConfiguration {
#Value("${" + EmbeddedKafkaBroker.SPRING_EMBEDDED_KAFKA_BROKERS + "}")
private String brokerAddresses;
#Bean(name = KafkaStreamsDefaultConfiguration.DEFAULT_STREAMS_CONFIG_BEAN_NAME)
public KafkaStreamsConfiguration kStreamsConfigs() {
Map<String, Object> props = new HashMap<>();
props.put(StreamsConfig.APPLICATION_ID_CONFIG, "testStreams");
props.put(StreamsConfig.BOOTSTRAP_SERVERS_CONFIG, this.brokerAddresses);
return new KafkaStreamsConfiguration(props);
}
}
and a simple test
#RunWith(SpringRunner.class)
#SpringBootTest
#EmbeddedKafka(topics = { "topic" })
public class EmbeddedKafkaTest {
#Autowired
private MyBean tested;
#Autowired
private EmbeddedKafkaBroker kafkaBroker;
#Test
public void loaded() {}
}
fails to run:
Parameter 0 of method kafkaStreamsFactoryBeanConfigurer in org.springframework.boot.autoconfigure.kafka.KafkaStreamsAnnotationDrivenConfiguration required a single bean, but 2 were found:
- &defaultKafkaStreamsBuilder: defined by method 'defaultKafkaStreamsBuilder' in class path resource [org/springframework/kafka/annotation/KafkaStreamsDefaultConfiguration.class]
- &stream-builder-process: defined in null
[...]
Caused by: org.springframework.context.ApplicationContextException: Failed to start bean 'outputBindingLifecycle'; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'kafkaStreamsFactoryBeanConfigurer' defined in org.springframework.boot.autoconfigure.kafka.KafkaStreamsAnnotationDrivenConfiguration: Unsatisfied dependency expressed through method 'kafkaStreamsFactoryBeanConfigurer' parameter 0; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'org.springframework.kafka.config.StreamsBuilderFactoryBean' available: expected single matching bean but found 2: &defaultKafkaStreamsBuilder,&stream-builder-process
If I remove the #SpringBootTest from the test class, the problem disappears, but then the actual bean under test fails to autowire.
I don't define a StreamBuilderFactoryBean myself, where are they coming from?
Also: is this this setup even worthwhile for testing a stream that is used to feed a KTable that is later being queried? It's not like I can "use a different topic for each test" since the stream will always use the same topic. My hope is that I can get around that with proper test case design, or am I going to hit a wall I can't see yet?
According to you stack trace, you also use Spring Cloud Stream with Kafka Streams Binder. Please, add an appropriate tag.
Consider to remove an explicit #EnableKafkaStreams since Binder is going to take care about infrastructure for you.
I am writing a project with Spring Boot 1.5.8.
I have some Entity classes which are generated and contain bean (for Example FooBean) which only exists in request scope. What is important: i am not able to change that part of code. So assume that i have an Entty:
#Enitty
public class FooEntity{
#Transient protected FooBean fooBean;
}
and FooBean implementation:
#Component
#Scope(value = WebApplicationContext.SCOPE_REQUEST, proxyMode = ScopedProxyMode.TARGET_CLASS)
public class FooBean {
...
}
I also have some part of code where i have method which should be runned by Spring CRON:
#Scheduled(cron = "0 0/2 * * * ?")
#Transactional(value = Transactional.TxType.REQUIRES_NEW)
void scheduledTask() {
...
}
What's important: in that scheduledTask i am saving some instances of FooEntity to DB.
And of course: When i try to invoke repository.saveAll() Spring is throwing an exception:
Caused by: org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'scopedTarget.fooBean ': Scope 'request' is not active for the current thread;
Is there any possibility to resolve that problem? How can I override this scoped bean so it will be available in not-request scope?
I think I'm writing a little bit later :) but you can create your own instance of this bean.
In spring boot you can simply create your own singleton instance of the bean like this:
#Configuration
#EnableScheduling
public class ApiConfig {
#Bean
#Primary
public FooBean fooBean(){
return new FooBean();
}
}
In case your bean has some dependencies in constructor (constructor autowired) which has to be autowired you can simply put those beans in method params and spring will provide it for you like this:
#Bean
#Primary
public FooBean fooBean(BeanToAutowire myBean){
return new FooBean(myBean);
}
In case your bean has no constructor autowired dependencies but annotation autowired (using #Autowired) you can simple do it like this:
#Bean
#Primary
public FooBean fooBean(AutowireCapableBeanFactory beanFactory){
FooBean bean = new FooBean(myBean);
beanFactory.autowireBean(bean); // here spring will autowire all dependencies for you
return bean;
}
It is not the most elegant way to do it but it works. Side effect is that there will be two instances of FooBean in app context but spring will use your instance because you set this instance as primary using #Primary annotation. Only beans which use Autowired annotation together with qualifier annotation can choose which instance of FooBean will be autowired.
Please explain the following about NoSuchBeanDefinitionException exception in Spring:
What does it mean?
Under what conditions will it be thrown?
How can I prevent it?
This post is designed to be a comprehensive Q&A about occurrences of NoSuchBeanDefinitionException in applications using Spring.
The javadoc of NoSuchBeanDefinitionException explains
Exception thrown when a BeanFactory is asked for a bean instance for
which it cannot find a definition. This may point to a non-existing
bean, a non-unique bean, or a manually registered singleton instance
without an associated bean definition.
A BeanFactory is basically the abstraction representing Spring's Inversion of Control container. It exposes beans internally and externally, to your application. When it cannot find or retrieve these beans, it throws a NoSuchBeanDefinitionException.
Below are simple reasons why a BeanFactory (or related classes) would not be able to find a bean and how you can make sure it does.
The bean doesn't exist, it wasn't registered
In the example below
#Configuration
public class Example {
public static void main(String[] args) throws Exception {
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(Example.class);
ctx.getBean(Foo.class);
}
}
class Foo {}
we haven't registered a bean definition for the type Foo either through a #Bean method, #Component scanning, an XML definition, or any other way. The BeanFactory managed by the AnnotationConfigApplicationContext therefore has no indication of where to get the bean requested by getBean(Foo.class). The snippet above throws
Exception in thread "main" org.springframework.beans.factory.NoSuchBeanDefinitionException:
No qualifying bean of type [com.example.Foo] is defined
Similarly, the exception could have been thrown while trying to satisfy an #Autowired dependency. For example,
#Configuration
#ComponentScan
public class Example {
public static void main(String[] args) throws Exception {
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(Example.class);
}
}
#Component
class Foo { #Autowired Bar bar; }
class Bar { }
Here, a bean definition is registered for Foo through #ComponentScan. But Spring knows nothing of Bar. It therefore fails to find a corresponding bean while trying to autowire the bar field of the Foo bean instance. It throws (nested inside a UnsatisfiedDependencyException)
Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException:
No qualifying bean of type [com.example.Bar] found for dependency [com.example.Bar]:
expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {#org.springframework.beans.factory.annotation.Autowired(required=true)}
There are multiple ways to register bean definitions.
#Bean method in a #Configuration class or <bean> in XML configuration
#Component (and its meta-annotations, eg. #Repository) through #ComponentScan or <context:component-scan ... /> in XML
Manually through GenericApplicationContext#registerBeanDefinition
Manually through BeanDefinitionRegistryPostProcessor
...and more.
Make sure the beans you expect are properly registered.
A common error is to register beans multiple times, ie. mixing the options above for the same type. For example, I might have
#Component
public class Foo {}
and an XML configuration with
<context:component-scan base-packages="com.example" />
<bean name="eg-different-name" class="com.example.Foo />
Such a configuration would register two beans of type Foo, one with name foo and another with name eg-different-name. Make sure you're not accidentally registering more beans than you wanted. Which leads us to...
If you're using both XML and annotation-based configurations, make sure you import one from the other. XML provides
<import resource=""/>
while Java provides the #ImportResource annotation.
Expected single matching bean, but found 2 (or more)
There are times when you need multiple beans for the same type (or interface). For example, your application may use two databases, a MySQL instance and an Oracle one. In such a case, you'd have two DataSource beans to manage connections to each one. For (simplified) example, the following
#Configuration
public class Example {
public static void main(String[] args) throws Exception {
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(Example.class);
System.out.println(ctx.getBean(DataSource.class));
}
#Bean(name = "mysql")
public DataSource mysql() { return new MySQL(); }
#Bean(name = "oracle")
public DataSource oracle() { return new Oracle(); }
}
interface DataSource{}
class MySQL implements DataSource {}
class Oracle implements DataSource {}
throws
Exception in thread "main" org.springframework.beans.factory.NoUniqueBeanDefinitionException:
No qualifying bean of type [com.example.DataSource] is defined:
expected single matching bean but found 2: oracle,mysql
because both beans registered through #Bean methods satisfied the requirement of BeanFactory#getBean(Class), ie. they both implement DataSource. In this example, Spring has no mechanism to differentiate or prioritize between the two. But such mechanisms exists.
You could use #Primary (and its equivalent in XML) as described in the documentation and in this post. With this change
#Bean(name = "mysql")
#Primary
public DataSource mysql() { return new MySQL(); }
the previous snippet would not throw the exception and would instead return the mysql bean.
You can also use #Qualifier (and its equivalent in XML) to have more control over the bean selection process, as described in the documentation. While #Autowired is primarily used to autowire by type, #Qualifier lets you autowire by name. For example,
#Bean(name = "mysql")
#Qualifier(value = "main")
public DataSource mysql() { return new MySQL(); }
could now be injected as
#Qualifier("main") // or #Qualifier("mysql"), to use the bean name
private DataSource dataSource;
without issue. #Resource is also an option.
Using wrong bean name
Just as there are multiple ways to register beans, there are also multiple ways to name them.
#Bean has name
The name of this bean, or if plural, aliases for this bean. If left
unspecified the name of the bean is the name of the annotated method.
If specified, the method name is ignored.
<bean> has the id attribute to represent the unique identifier for a bean and name can be used to create one or more aliases illegal in an (XML) id.
#Component and its meta annotations have value
The value may indicate a suggestion for a logical component name, to
be turned into a Spring bean in case of an autodetected component.
If that's left unspecified, a bean name is automatically generated for the annotated type, typically the lower camel case version of the type name. For example MyClassName becomes myClassName as its bean name. Bean names are case sensitive. Also note that wrong names/capitalization typically occur in beans referred to by string like #DependsOn("my BeanName") or XML config files.
#Qualifier, as mentioned earlier, lets you add more aliases to a bean.
Make sure you use the right name when referring to a bean.
More advanced cases
Profiles
Bean definition profiles allow you to register beans conditionally. #Profile, specifically,
Indicates that a component is eligible for registration when one or
more specified profiles are active.
A profile is a named logical grouping that may be activated
programmatically via
ConfigurableEnvironment.setActiveProfiles(java.lang.String...) or
declaratively by setting the spring.profiles.active property as a JVM
system property, as an environment variable, or as a Servlet context
parameter in web.xml for web applications. Profiles may also be
activated declaratively in integration tests via the #ActiveProfiles
annotation.
Consider this examples where the spring.profiles.active property is not set.
#Configuration
#ComponentScan
public class Example {
public static void main(String[] args) throws Exception {
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(Example.class);
System.out.println(Arrays.toString(ctx.getEnvironment().getActiveProfiles()));
System.out.println(ctx.getBean(Foo.class));
}
}
#Profile(value = "StackOverflow")
#Component
class Foo {
}
This will show no active profiles and throw a NoSuchBeanDefinitionException for a Foo bean. Since the StackOverflow profile wasn't active, the bean wasn't registered.
Instead, if I initialize the ApplicationContext while registering the appropriate profile
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext();
ctx.getEnvironment().setActiveProfiles("StackOverflow");
ctx.register(Example.class);
ctx.refresh();
the bean is registered and can be returned/injected.
AOP Proxies
Spring uses AOP proxies a lot to implement advanced behavior. Some examples include:
Transaction management with #Transactional
Caching with #Cacheable
Scheduling and asynchronous execution with #Async and #Scheduled
To achieve this, Spring has two options:
Use the JDK's Proxy class to create an instance of a dynamic class at runtime which only implements your bean's interfaces and delegates all method invocations to an actual bean instance.
Use CGLIB proxies to create an instance of a dynamic class at runtime which implements both interfaces and concrete types of your target bean and delegates all method invocations to an actual bean instance.
Take this example of JDK proxies (achieved through #EnableAsync's default proxyTargetClass of false)
#Configuration
#EnableAsync
public class Example {
public static void main(String[] args) throws Exception {
AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(Example.class);
System.out.println(ctx.getBean(HttpClientImpl.class).getClass());
}
}
interface HttpClient {
void doGetAsync();
}
#Component
class HttpClientImpl implements HttpClient {
#Async
public void doGetAsync() {
System.out.println(Thread.currentThread());
}
}
Here, Spring attempts to find a bean of type HttpClientImpl which we expect to find because the type is clearly annotated with #Component. However, instead, we get an exception
Exception in thread "main" org.springframework.beans.factory.NoSuchBeanDefinitionException:
No qualifying bean of type [com.example.HttpClientImpl] is defined
Spring wrapped the HttpClientImpl bean and exposed it through a Proxy object that only implements HttpClient. So you could retrieve it with
ctx.getBean(HttpClient.class) // returns a dynamic class: com.example.$Proxy33
// or
#Autowired private HttpClient httpClient;
It's always recommended to program to interfaces. When you can't, you can tell Spring to use CGLIB proxies. For example, with #EnableAsync, you can set proxyTargetClass to true. Similar annotations (EnableTransactionManagement, etc.) have similar attributes. XML will also have equivalent configuration options.
ApplicationContext Hierarchies - Spring MVC
Spring lets you build ApplicationContext instances with other ApplicationContext instances as parents, using ConfigurableApplicationContext#setParent(ApplicationContext). A child context will have access to beans in the parent context, but the opposite is not true. This post goes into detail about when this is useful, particularly in Spring MVC.
In a typical Spring MVC application, you define two contexts: one for the entire application (the root) and one specifically for the DispatcherServlet (routing, handler methods, controllers). You can get more details here:
Difference between applicationContext.xml and spring-servlet.xml in Spring Framework
It's also very well explained in the official documentation, here.
A common error in Spring MVC configurations is to declare the WebMVC configuration in the root context with #EnableWebMvc annotated #Configuration classes or <mvc:annotation-driven /> in XML, but the #Controller beans in the servlet context. Since the root context cannot reach into the servlet context to find any beans, no handlers are registered and all requests fail with 404s. You won't see a NoSuchBeanDefinitionException, but the effect is the same.
Make sure your beans are registered in the appropriate context, ie. where they can be found by the beans registered for WebMVC (HandlerMapping, HandlerAdapter, ViewResolver, ExceptionResolver, etc.). The best solution is to properly isolate beans. The DispatcherServlet is responsible for routing and handling requests so all related beans should go into its context. The ContextLoaderListener, which loads the root context, should initialize any beans the rest of your application needs: services, repositories, etc.
Arrays, collections, and maps
Beans of some known types are handled in special ways by Spring. For example, if you tried to inject an array of MovieCatalog into a field
#Autowired
private MovieCatalog[] movieCatalogs;
Spring will find all beans of type MovieCatalog, wrap them in an array, and inject that array. This is described in the Spring documentation discussing #Autowired. Similar behavior applies to Set, List, and Collection injection targets.
For a Map injection target, Spring will also behave this way if the key type is String. For example, if you have
#Autowired
private Map<String, MovieCatalog> movies;
Spring will find all beans of type MovieCatalog and add them as values to a Map, where the corresponding key will be their bean name.
As described previously, if no beans of the requested type are available, Spring will throw a NoSuchBeanDefinitionException. Sometimes, however, you just want to declare a bean of these collection types like
#Bean
public List<Foo> fooList() {
return Arrays.asList(new Foo());
}
and inject them
#Autowired
private List<Foo> foos;
In this example, Spring would fail with a NoSuchBeanDefinitionException because there are no Foo beans in your context. But you didn't want a Foo bean, you wanted a List<Foo> bean. Before Spring 4.3, you'd have to use #Resource
For beans that are themselves defined as a collection/map or array
type, #Resource is a fine solution, referring to the specific
collection or array bean by unique name. That said, as of 4.3,
collection/map and array types can be matched through Spring’s
#Autowired type matching algorithm as well, as long as the element
type information is preserved in #Bean return type signatures or
collection inheritance hierarchies. In this case, qualifier values can
be used to select among same-typed collections, as outlined in the
previous paragraph.
This works for constructor, setter, and field injection.
#Resource
private List<Foo> foos;
// or since 4.3
public Example(#Autowired List<Foo> foos) {}
However, it will fail for #Bean methods, ie.
#Bean
public Bar other(List<Foo> foos) {
new Bar(foos);
}
Here, Spring ignores any #Resource or #Autowired annotating the method, because it's a #Bean method, and therefore can't apply the behavior described in the documentation. However, you can use Spring Expression Language (SpEL) to refer to beans by their name. In the example above, you could use
#Bean
public Bar other(#Value("#{fooList}") List<Foo> foos) {
new Bar(foos);
}
to refer to the bean named fooList and inject that.