How to get bean using application context in spring boot

Question

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.

Answer 1

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) 

Answer 2

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().