I am building a basic program of "hello world" in SpringBoot
Code
MyController.java
package controllers;
import org.springframework.stereotype.Controller;
#Controller
public class MyController {
public String hello() {
System.out.println("Hello World");
return "foo";
}
}
DemoApplication.java
package di.prac;
import java.util.Arrays;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContext;
import controllers.MyController;
#SpringBootApplication
public class DemoApplication {
public static void main(String[] args) {
ApplicationContext ctx=SpringApplication.run(DemoApplication.class, args);
MyController m = (MyController)ctx.getBean("myController");
m.hello();
System.out.println("*******"+Arrays.asList(ctx.getBeanDefinitionNames()));
}
}
I am using eclipse and created this project from http://start.spring.io/ without any dependencies.
I learned that Spring create the bean of MyController class with name myController ,but Spring is not able to find myController bean
ERROR
Exception in thread "main"
org.springframework.beans.factory.NoSuchBeanDefinitionException: No
bean named 'myController' available at
org.springframework.beans.factory.support.DefaultListableBeanFactory.getBeanDefinition(DefaultListableBeanFactory.java:686)
at
org.springframework.beans.factory.support.AbstractBeanFactory.getMergedLocalBeanDefinition(AbstractBeanFactory.java:1210)
at
org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:291)
at
org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:199)
at
org.springframework.context.support.AbstractApplicationContext.getBean(AbstractApplicationContext.java:1089)
at di.prac.DemoApplication.main(DemoApplication.java:16)
Please find and explain the error in the Project
Place your controller under sub package of di.prac like di.prac.controllers or use #ComponentScan on your controller. By default, Spring scans the current and sub packages where your main application is present. If you want to scan other packages too, then you can specify the packages in #SpringBootApplication as an argument like.
#SpringBootApplication(scanBasePackages = {"com.xyz.controllers", "com.abc.models""})
We should avoid putting the #Configuration class in the default package (i.e. by not specifying the package at all). In this case, Spring scans all the classes in all jars in a classpath. That causes errors and the application probably doesn't start.
For your controller to be available in the context of Spring, you need to define that it is managed by the Spring container. Only the #Controller annotation is not enough, it indicates only the stereotype of your bean, as well as the annotations #Repository and #Service.
In cases where the beans have these annotations and are managed by Spring, it is because their packages that the spring is scanning to search for them has been specified programmatically or per xml. In your case, you should annotate your DemoApplication class with 2 other annotations:
#Configuration - Allows access to spring context
#ComponentScan - Packages to be scanned by Spring
#Configuration
#ComponentScan (basePackages = {"controllers"})
public class DemoApplication {
public static void main(String[] args) {
ApplicationContext ctx=SpringApplication.run(DemoApplication.class, args);
MyController m = (MyController)ctx.getBean("myController");
m.hello();
System.out.println(Arrays.asList(ctx.getBeanDefinitionNames()));
}
}
Just encountered same problem, solution is simple.You just (me also) created package "controllers" on the wrong place. It should be created not in java folder but under folder with name of your project. Simple but deadly mistake. Your code is written perfectly fine.
Related
I have following:
#SpringBootApplication(scanBasePackages = {"com.my.package","com.my.package.mylibrary"})
#EnableAsync
#EnableSwagger2
#ServletComponentScan
#EnableAutoConfiguration(exclude = {DataSourceAutoConfiguration.class, DataSourceTransactionManagerAutoConfiguration.class,
HibernateJpaAutoConfiguration.class})
public class MySpringBootApplication {....}
This application has package com.my.package, and it also has a library dependency containing spring beans I want to autowire in this application, and those beans are in package com.my.package.mylibrary inside library.
So I have put both for scanBasePackages. But Spring is not able to find beans from the library?
Edit:
From library, I have:
package com.my.package.mylibrary.repository;
....
public interface MyRepository extends JpaRepository<..., ....> {....}
In application, I have:
package com.my.package.controller;
....
#RestController
public class MyController {....}
MySpringBootApplication resides in com.my.package.
Error:
Exception in thread "main" java.lang.NoClassDefFoundError: com/my/package/mylibrary/repository/MyRepository
at com.my.package.MySpringBootApplication.main(MySpringBootApplication.java:32)
Caused by: java.lang.ClassNotFoundException: com.my.package.mylibrary.repository.MyRepository
at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:602)
at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:178)
at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:522)
I added #EnableJpaRepositories for repository package. Now I see error related to entity MyEntity which MyRepository is based upon.
"java.lang.TypeNotPresentException: Type com.my.package.mylibrary.domain.MyEntity not present
So I added #EntityScan for "com.my.package.mylibrary.domain", but that makes application stuck infinitely.
First of all, you don't need to add scanBasePackages attribute in #SpringBootApplication as the base package is com.my.package.
If package is totally different, then you could have added it.
Spring Boot will automatically pick up the bean if the base package is same.
There is something called as separation of concerns that you should follow when you are writing code.
Update your MySpringBootApplication class to this :
#SpringBootApplication
#ServletComponentScan
public class MySpringBootApplication {....}
Create a separate config for asynchronous method execution.
#Configuration
#EnableAsync
public class AsynchronousConfig {.....}
Create a separate config class for Swagger 2.
#Configuration
#EnableSwagger2
public class SwaggerConfiguration {....}
Create separate config to exclude configuration.
#Configuration
#EnableAutoConfiguration(exclude = {DataSourceAutoConfiguration.class,
DataSourceTransactionManagerAutoConfiguration.class,
HibernateJpaAutoConfiguration.class})
public class ExcludeConfigurationFile {....}
Note: Spring boot auto configuration will automatically pick up these #Configuration files
This should work.
You might want to scan the packages seperately and change your JpaRepository to CrudRepository. The configuration to seperate the layer is as follow.
#SpringBootApplication(scanBasePackages = {"com.my.package.controller"})
#EnableJpaRepositories(basePackages = {"com.my.package.mylibrary.repository"})
#EntityScan(basePackages = {"com.my.package.mylibrary.domain"})
public class MySpringBootApplication {
public static void main(String[] args) {
MySpringBootApplication.run(MySpringBootApplication.class, args);
}
}
This question already has answers here:
How can I #Autowire a spring bean that was created from an external jar?
(5 answers)
Closed 3 years ago.
I have a Spring Boot project and I can't get components from an external jar to be autowired. When I try to, I got a org.springframework.beans.factory.NoSuchBeanDefinitionException saying that can't find a bean with that name available.
I tried some solutions found in similar questions, like these ones:
How to autowire #service from external Jar in Spring
Spring Boot #autowired does not work, classes in different package
How can I #Autowire a spring bean that was created from an external jar?
..but still can't managed it to work.
Here is an example of what I'm trying to accomplish:
Here is boot class in the Spring Boot project spring-project-example
package com.springdi.example;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ConfigurableApplicationContext;
import org.springframework.context.annotation.ComponentScan;
import com.dependency.example.DependencyBasePackageClass;
import com.dependency.example.somepackage.SomeBean;
#SpringBootApplication
#ComponentScan(basePackages = {"com.springdi.example"}, basePackageClasses = DependencyBasePackageClass.class)
public class SpringProjectExampleApplication {
public static void main(String[] args) {
ConfigurableApplicationContext context = SpringApplication.run(SpringProjectExampleApplication.class, args);
String beanName = SomeBean.class.getName();
System.out.printf("%s can be autowired: %s\n", beanName, String.valueOf(context.containsBean(beanName)).toUpperCase());
}
}
It's just a simple Spring Boot project checking if it is possible to autowire a component present in the dependency jar.
Here is the component in the jar (dependency-example-1.0.0.jar)
package com.dependency.example.somepackage;
import org.springframework.stereotype.Component;
#Component
public class SomeBean {
public void someMethod() {
System.out.println("Some process...");
}
}
And here is the base package class of this same jar
package com.dependency.example;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
/**
* Just a class to serve as the root for component
* scanning in "com.dependency.example" and its sub-packages
*/
#Configuration
#ComponentScan
public class DependencyBasePackageClass {
}
I've already tried #Import(DependencyBasePackageClass.class) in SpringProjectExampleApplication and #ComponentScan with basePackages and basePackageClasses, but no success.
I also tried using #SpringBootApplication(scanBasePackageClasses = {SpringProjectExampleApplication.class, DependencyBasePackageClass.class})
and the not type safe #SpringBootApplication(scanBasePackages = {"com.springdi.example", "com.dependency.example"}).
#Configuration #ComponentScan({"com.dependency.example"}) also fails, context.containsBean("com.dependency.example.somepackage.SomeBean") still returns false.
This jar is included in classpath and in the pom.xml as a dependency
<dependencies>
<!-- other dependencies -->
<dependency>
<groupId>com.rbaggio</groupId>
<artifactId>dependency-example</artifactId>
<version>1.0.0</version>
<scope>system</scope>
<systemPath>${basedir}/lib/dependency-example-1.0.0.jar</systemPath>
</dependency>
</dependencies>
Could it be the location of the jar, the way it is included or some extra configuration needed?
I'd appreciate any help! Thanks in advance.
Okey some basic things, you have mixed up your packages a bit.
#SpringBootApplication will scan all classes in packages below the class this is annotated on. This annotation is an alias for #EnableAutoConfiguration, #Configuration and #ComponentScan means that #ComponentScan(basePackages = {"com.springdi.example"}, basePackageClasses = DependencyBasePackageClass.class) is not needed.
com.springdi.example // class with #SpringBootApplication annotation
|
|
|
com.springdi.example.* // Will find all #Service, #Component, #Configuration
// in subpackages below the #SpringBootApplication
// annotation
You can read more about the annotation here SpringBootApplication
Since your other annotated classes are NOT in the same package structure as the #SpringBootApplication you need to define all the places you want to scan for annotations.
#SpringBootApplication(scanBasePackages = {"com.springdi.example", "com.dependency.example"})
will probably include all the packages that you want to scan through.
I am working with spring boot tutorial from javabrains and everything was clear until putting CrudRepository inside project. Below you can find my main class:
package pl.springBootStarter.app;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class CourseApiDataApplication
{
public static void main(String args[])
{
SpringApplication.run(CourseApiDataApplication.class,args);
}
}
Service class:
package pl.springBootStarter.app.topic;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
#Service
public class TopicService
{
#Autowired
private TopicRepository topicRepository;
private List<Topic> topics = new ArrayList<>(Arrays.asList(
new Topic("spring","spring framework", "spring framework dectription"),
new Topic("sprin","spring framework", "spring framework dectription"),
new Topic("spri","spring framework", "spring framework dectription")));
public List<Topic> getAllTopics()
{
// return topics;
List<Topic> t = new ArrayList<Topic>();
topicRepository.findAll().forEach(t::add);
return t;
}
public Topic getTopic (String id)
{
return topics.stream().filter( t -> t.getId().equals(id)).findFirst().get();
}
public void addTopic(Topic topic) {
topicRepository.save(topic);
}
public void updateTopic(Topic topic, String id)
{
topics.set(topics.indexOf(topics.stream().filter(t-> t.getId().equals(id)).findFirst().get()), topic);
}
public void deleteTopic(String id)
{
topics.remove(topics.stream().filter(t -> t.getId().equals(id)).findFirst().get());
}
}
And Repository interface:
package pl.springBootStarter.app.topic;
import org.springframework.data.repository.CrudRepository;
public interface TopicRepository extends CrudRepository<Topic,String>
{
}
When I run the app there is a problem with injection of TopicRepository into topicRepository field in TopicService class. I get following error:
Error starting ApplicationContext. To display the conditions report re- run your application with 'debug' enabled.
2019-05-01 10:33:52.206 ERROR 6972 --- [ main] o.s.b.d.LoggingFailureAnalysisReporter :
***************************
APPLICATION FAILED TO START
***************************
Description:
Field topicRepository in pl.springBootStarter.app.topic.TopicService required a bean of type 'pl.springBootStarter.app.topic.TopicRepository' that could not be found.
The injection point has the following annotations:
- #org.springframework.beans.factory.annotation.Autowired(required=true)
What could be the reason that Spring cannot do the autowiring?
Be sure the class is scanned by spring!
(this may help if that's the problem:
Intellij Springboot problems on startup).
Optionally you may want to annotate TopicRepository as a #Repository.
#Repository
public interface TopicRepository extends CrudRepository<Topic,String>
{
}
See a demo code here: https://github.com/lealceldeiro/repository-demo
Spring cannot inject bean because it has not been created.
You have to instruct Spring to generate implementation of declared repository interfaces by using #EnableJpaRepositories(basePackages={"pl.springBootStarter.app"}) annotation on any of your configuration classes or class annotated with #SpringBootApplication. That should fix your problem.
I got a similar message and I was missing the #Service annotation in the Service class. Simple mistake, posting in case it helps anyone else.
For anybody who was brought here by googling the generic bean error message, but who is actually trying to add a feign client to their Spring Boot application via the #FeignClient annotation on your client interface, none of the above solutions will work for you.
To fix the problem, you need to add the #EnableFeignClients annotation to your Application class, like so:
#SpringBootApplication
// ... (other pre-existing annotations) ...
#EnableFeignClients // <------- THE IMPORTANT ONE
public class Application {
I got a similar message.
the thing was my main package was com.example
and the package for other classes was com.xyz
so when I Changed the name of the package of other class to com.example.topic
i.e.
finally
The main package was com.example
and the package for the other class was com.example.topic
A simple mistake, posting in case it helps anyone else.
In my cases, the necessary configuration from org.springframework.boot.autoconfigure.jdbc. has been excluded at SpringBootApplication, causing relevant bean not added properly. Check your main application java file and see if you can find following configuration in the exclusion list
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;
import org.springframework.boot.autoconfigure.jdbc.DataSourceTransactionManagerAutoConfiguration;
#SpringBootApplication(
exclude = {
DataSourceAutoConfiguration.class, // REMOVE THIS
DataSourceTransactionManagerAutoConfiguration.class, // REMOVE THIS
}
)
and remove them from exclusion list.
in service class
do:
#Autowired(required=false)
I have packaged my entire entities of the application and the repository interfaces into one jar. The repositories are written with #Repository annotation:
#Repository
public interface InternalUserRepository extends JpaRepository<InternalUser, Long>{
}
I have included this jar file inside my spring boot application and trying to autowire the interface like this from a controller:
#RestController
public class AuthenticationController {
#Autowired
AuthenticationService authenticationService;
#Autowired
InternalUserRepository internalUserRepository;
#GetMapping("/")
public String home() {
return "Hello World!";
}
}
My Main app class is written like:
#SpringBootApplication
#EnableJpaRepositories
#ComponentScan("com.cdac.dao.cdacdao.*")
public class CdacAuthenticationMgntApplication {
public static void main(String[] args) {
SpringApplication.run(CdacAuthenticationMgntApplication.class, args);
}
}
The repository is not getting autowired. When I am firing up the Spring boor application I am getting the following error:
***************************
APPLICATION FAILED TO START
***************************
Description:
Field internalUserRepository in
com.cdac.user.cdacauthenticationmgnt.controller.AuthenticationController required a bean of type 'com.cdac.dao.cdacdao.repository.InternalUserRepository' that could not be found.
Action:
Consider defining a bean of type 'com.cdac.dao.cdacdao.repository.InternalUserRepository' in your configuration.
Have anyone tried similar architecture like this?
If your JPA repositories are in a different package than your Spring Boot application class, you have to specify that package on the EnableJpaRepositories annotation, not Component:
#EnableJpaRepositories("com.cdac.dao.cdacdao")
The package you specified on ComponentScan is for detecting classes as regular Spring beans, not repository interfaces.
As I remember, #ComponentScan should take a complete path to a package, so I think that your package.* does not work.
Try to use type-safe component scan instead:
// You refer to your packages of your base project and your module here.
// Choose the class so that their package is cover all child package
#SpringBootApplication(scanBasePackageClasses = {xxx. InternalUserRepository.class, xxx.CdacAuthenticationMgntApplication.class})
#EnableJpaRepositories
// No need to explicit #ComponentScan
public class CdacAuthenticationMgntApplication {
Or you can try #EnableJpaRepositories("com.cdac.dao.cdacdao")
Either way, you should pick the class in the most outer package (Spring will aslo try to find bean in sub package of those component scan packages)
Annotation #SpringBootApplication has supported all function
So we don't need config manually
#Retention(RetentionPolicy.RUNTIME)
#Documented
#Inherited
#SpringBootConfiguration
#EnableAutoConfiguration
#ComponentScan(excludeFilters = {
#Filter(type = FilterType.CUSTOM, classes = TypeExcludeFilter.class),
#Filter(type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) })
I am pretty new to Spring Boot Application. I wanted to understand how does a spring Boot Application create beans without #Configuration class . I had a look at a sample project where there was neither #Bean definitions nor a component scan yet #Autowired provided the dependency to the class. Please have a look at the snippet below:
#RestController
public class RestController{
**#Autowired
public CertificationService certificationService;**
.
.
.
.
}
//Interface
public interface CertificationService{
public List<Certification> findAll();
}
//Implementation Class
#Transactional
#Service
public class CertificationServiceImpl{
public List<Certification> findAll(){
.
.
}
}
My limited knowledge of springs tells me that when there is a #Service annotation over a class, there has to be a #ComponentScan somewhere to create the bean. But without a component scan, how does the CertificationServiceImpl bean gets created and thereby how does the autowiring of CertificationService in RestController works here?
As said in documentation:
... The #SpringBootApplication annotation is equivalent to using
#Configuration, #EnableAutoConfiguration and #ComponentScan...
Let say you have Spring Boot app class something like:
package com.mypackage;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
#SpringBootApplication
public class SpringBootApplication {
public static void main(String[] args) {
SpringApplication.run(SpringBootApplication.class, args);
}
}
Then all packages below of package com.mypackage will be scanned by default for Spring components. By the way, you can specify packages to scan right in #SpringBootApplication annotation, without usage of #ComponentScan. More details here.