Understanding the @Order Annotation in Spring Boot

The @Order annotation in Spring Boot allows you to control the order in which components are loaded or executed within the application context. It is commonly used when you have multiple components of the same type and you want to specify the order in which they should be processed. Below is a tutorial that demonstrates the use of @Order in a Spring Boot application.

Step 1: Create a Spring Boot Project

Use Spring Initializer or your preferred method to create a new Spring Boot project.

Step 2: Define Components

Create multiple components that will be ordered. For this example, let’s create two components: FirstComponent and SecondComponent.

Step 3: Create a Runner Class

Create a runner class to demonstrate the order in which components are loaded.

Step 4: Run the Application

Run the Spring Boot application. You should see the components and the runner being initialized in the order specified by the @Order annotation.

Step 5: Observations

• Components and runners with lower order values are processed first.
• If two components have the same order value, their order is determined by the order in which they are discovered by the Spring container.
• The runner class implements CommandLineRunner to demonstrate that components are ordered even within the run method.

Conclusion:

In this tutorial, you learned how to use the @Order annotation in a Spring Boot application to control the order of component loading. This can be particularly useful when dealing with multiple components of the same type, ensuring they are processed in the desired order within the Spring context.