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list of all beans Spring boot application

list of all beans Spring boot application

In a Spring Boot application, you may sometimes need to retrieve and inspect the list of all beans managed by the Spring container. This can be useful for debugging, testing, or understanding the application’s context. You can achieve this using the `ApplicationContext` which holds all the bean definitions and their instances.

Key Methods to Get Beans:

  • Using `ApplicationContext.getBeansOfType(Class<T> type)`: Retrieves all beans of a specific type.
  • Using `ApplicationContext.getBeanDefinitionNames()`: Lists all bean names defined in the application context.

beans Spring boot application

”1.
Example:

To get all beans of a specific type, such as `MyService`, you can use `ApplicationContext.getBeansOfType()`.

Define a Service Class:
```java
package com.example.demo.service;

import org.springframework.stereotype.Service;

@Service
public class MyService {
    public String getName() {
        return "MyService";
    }
}
```

Define Another Service Class:
```java
package com.example.demo.service;

import org.springframework.stereotype.Service;

@Service
public class AnotherService {
    public String getName() {
        return "AnotherService";
    }
}
```

Access Beans in a Component:
```java
package com.example.demo.component;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;

@Component
public class BeanLister {

    @Autowired
    private ApplicationContext applicationContext;

    @PostConstruct
    public void listBeans() {
        // Get all beans of type MyService
        Map<String, MyService> beans = applicationContext.getBeansOfType(MyService.class);
        beans.forEach((name, bean) -> {
            System.out.println("Bean name: " + name + ", Bean: " + bean.getName());
        });
    }
}
```

Explanation

  • @Autowired: Injects the ApplicationContext into the component.
  • applicationContext.getBeansOfType(MyService.class): Retrieves all beans of type MyService and prints their names.

2. Using ApplicationContext.getBeanDefinitionNames()

Example:

To list all bean names defined in the application context:

Access Beans in a Component:
```java
package com.example.demo.component;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;

@Component
public class BeanLister {

    @Autowired
    private ApplicationContext applicationContext;

    @PostConstruct
    public void listAllBeanNames() {
        // Get all bean names
        String[] beanNames = applicationContext.getBeanDefinitionNames();
        for (String beanName : beanNames) {
            System.out.println("Bean name: " + beanName);
        }
    }
}
```

Explanation:

  • applicationContext.getBeanDefinitionNames(): Retrieves all bean names and prints them.

Conclusion list of all beans Spring boot application

  • Get Beans of a Specific Type:
    • Method: Use applicationContext.getBeansOfType(Class<T> type).
    • Example: Retrieves and lists all beans of type MyService.

  • List All Bean Names:
    • Method: Use applicationContext.getBeanDefinitionNames().
    • Example: Lists all bean names defined in the application context.

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