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Discover how to automatically invoke methods from all `-Bean` or `-Component` implementations of a specific interface in Spring Boot. Learn effective scanning techniques for your applications.
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How to Scan All -Bean or -Component of a Specific Type in Spring Boot

When working with Spring Boot, you may find yourself needing to automatically invoke methods from various implementations of an interface. This is particularly useful when developing libraries or applications where you have multiple implementations of a given interface. In this guide, we will explore how to scan for all beans of a specific type, specifically focusing on implementations of an interface annotated with -Bean or -Component.

The Problem: Accessing All Implementations

Suppose you have the following interface:

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You might also have several implementations of this interface, like so:

[[See Video to Reveal this Text or Code Snippet]]

Now, if you want to invoke the doSomething method of all the implementations when your Spring Boot application starts, you need an efficient way to access these beans.

The Solution: Techniques to Scan Beans

Spring Boot provides a few different ways to access all beans of a specific type. Let's break down the options you can use:

Option 1: Autowire a List of Dummy in a Spring Component

One straightforward approach is to autowire a list of the Dummy type into a Spring component. Here is a simple example:

[[See Video to Reveal this Text or Code Snippet]]

How it Works: Spring will automatically inject all beans of type Dummy into the listDummy variable, which you can then iterate over to call the doSomething method.

Option 2: Autowire a Map of Dummy in a Spring Component

If you want to keep track of the beans by name, you can autowire a Map instead. This is how you can do it:

[[See Video to Reveal this Text or Code Snippet]]

Benefit: Using a Map allows you to access specific beans by their names if needed, giving you more control over the implementations.

Option 3: Autowire ApplicationContext to Get All Beans

Another powerful option is to autowire the ApplicationContext directly. This method enables you to retrieve all beans of a specific type as follows:

[[See Video to Reveal this Text or Code Snippet]]

Flexibility: This approach gives you the most flexibility, as you can easily obtain and work with beans of any specified type using the ApplicationContext.

Conclusion

In this guide, we explored how to effectively scan for all -Bean or -Component implementations of a specific interface in Spring Boot. By utilizing one of the methods described above, you can easily invoke methods from all these implementations at application startup.

Now, you have the tools to automate the invocation of methods across multiple implementations, enhancing the modularity and reusability of your Spring Boot applications!