Three ways to use applicationcontextinitializer

ApplicationContextInitializer Is in Springboot The boot process (refresh Before the method ) call ,ApplicationContextInitializer The realization mainly includes 3 In the way ：
First create a class implementation ApplicationContextInitializer This interface , Implement the corresponding method .

import org.springframework.context.ApplicationContextInitializer;
import org.springframework.context.ConfigurableApplicationContext;

public class TestContextInitializer implements ApplicationContextInitializer {
    
    @Override
    public void initialize(ConfigurableApplicationContext applicationContext) {
    
        System.out.println(" I loaded it ！！！！！！！！！！！");
    }
}

1、 Use spring.factories The way
stay resource Next new /META-INF/spring.factories file .

2、application.properties Add configuration mode ：
For this way is through DelegatingApplicationContextInitializer In this initialization class initialize Method to get application.properties in context.initializer.classes The corresponding class and execute the corresponding initialize Method . Just make it happen ApplicationContextInitializer Added to application.properties that will do . as follows :
3、 Modify the startup method in the startup class .

package com.llq.testdemo;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.context.ApplicationContextInitializer;

@SpringBootApplication
public class TestDemoApplication {
    

    public static void main(String[] args) {
    
// SpringApplication.run(TestDemoApplication.class, args);
        SpringApplication application = new SpringApplication(TestDemoApplication.class);
        application.addInitializers(new TestContextInitializer());
        application.run(args);
    }

}