如何获取所有 Spring 管理的 Bean

1. Overview

In this article, we’ll explore different techniques for displaying all Spring-managed beans withing the container.

2. The IoC Container

A bean is the foundation of a Spring-managed application; all beans reside withing the IOC container, which is responsible for managing their life cycle.

We can get a list of all beans within this container in two ways:

1. Using a ListableBeanFactory interface
2. Using a Spring Boot Actuator

3. Using ListableBeanFactory Interface

The ListableBeanFactory interface provides getBeanDefinitionNames() method which returns the names of all the beans defined in this factory. This interface is implemented by all the bean factories that pre-loads their bean definitions to enumerate all their bean instances.

You can find the list of all known subinterfaces and its implementing classes in the official documentation.

For this example, we’ll be using a Spring Boot Application.

First, we’ll create some Spring beans. Let’s create a simple Spring Controller FooController:

@Controller
public class FooController {

    @Autowired
    private FooService fooService;
    
    @RequestMapping(value="/displayallbeans") 
    public String getHeaderAndBody(Map model){
        model.put("header", fooService.getHeader());
        model.put("message", fooService.getBody());
        return "displayallbeans";
    }
}

This Controller is dependent on another Spring bean FooService:

@Service
public class FooService {
    
    public String getHeader() {
        return "Display All Beans";
    }
    
    public String getBody() {
        return "This is a sample application that displays all beans "
          + "in Spring IoC container using ListableBeanFactory interface "
          + "and Spring Boot Actuators.";
    }
}

Note that we’ve created two different beans here:

1. fooController
2. fooService

While executing this application, we’ll use applicationContext object and call its getBeanDefinitionNames() method, which will return all the beans in our applicationContext container:

@SpringBootApplication
public class Application {
    private static ApplicationContext applicationContext;

    public static void main(String[] args) {
        applicationContext = SpringApplication.run(Application.class, args);
        displayAllBeans();
    }
    
    public static void displayAllBeans() {
        String[] allBeanNames = applicationContext.getBeanDefinitionNames();
        for(String beanName : allBeanNames) {
            System.out.println(beanName);
        }
    }
}

This will print all the beans from applicationContext container:

fooController
fooService
//other beans

Note that along with beans defined by us, it will also log all other beans that are in this container. For the sake of clarity, we’ve omitted them here because there are quite a lot of them.

4. Using Spring Boot Actuator

The Spring Boot Actuator functionality provides endpoints which are used for monitoring our application’s statistics.

It includes many built-in endpoints, including /beans. This displays a complete list of all the Spring managed beans in our application. You can find the full list of existing endpoints over on the official docs.

Now, we’ll just hit the URL http://

[
    {
        "context": "application:8080",
        "parent": null,
        "beans": [
            {
                "bean": "fooController",
                "aliases": [],
                "scope": "singleton",
                "type": "com.baeldung.displayallbeans.controller.FooController",
                "resource": "file [E:/Workspace/tutorials-master/spring-boot/target
                  /classes/com/baeldung/displayallbeans/controller/FooController.class]",
                "dependencies": [
                    "fooService"
                ]
            },
            {
                "bean": "fooService",
                "aliases": [],
                "scope": "singleton",
                "type": "com.baeldung.displayallbeans.service.FooService",
                "resource": "file [E:/Workspace/tutorials-master/spring-boot/target/
                  classes/com/baeldung/displayallbeans/service/FooService.class]",
                "dependencies": []
            },
            // ...other beans
        ]
    }
]