Using the ApplicationRunner or CommandLineRunner

If you need to run some specific code once the SpringApplication has started, you can implement the ApplicationRunner or CommandLineRunner interfaces. Both interfaces work in the same way and offer a single run method, which is called just before SpringApplication.run(…​) completes.

This contract is well suited for tasks that should run after application startup but before it starts accepting traffic.

The CommandLineRunner interfaces provides access to application arguments as a string array, whereas the ApplicationRunner uses the ApplicationArguments interface discussed earlier. The following example shows a CommandLineRunner with a run method:

  • Java

  • Kotlin

import org.springframework.boot.CommandLineRunner;
import org.springframework.stereotype.Component;

@Component
public class MyCommandLineRunner implements CommandLineRunner {

	@Override
	public void run(String... args) {
		// Do something...
	}

}
import org.springframework.boot.CommandLineRunner
import org.springframework.stereotype.Component

@Component
class MyCommandLineRunner : CommandLineRunner {

	override fun run(vararg args: String) {
		// Do something...
	}

}

If several CommandLineRunner or ApplicationRunner beans are defined that must be called in a specific order, you can additionally implement the org.springframework.core.Ordered interface or use the org.springframework.core.annotation.Order annotation.