1.static、construct、PostConstruct
package com.wlfy.www.teststartupsequence;

import org.springframework.stereotype.Component;

import javax.annotation.PostConstruct;

/**
 * @author wl
 * @description TestPostConstruct
 * @date 2022/4/8 21:01
 */
@Component
public class TestPostConstruct {
    static {
        System.out.println("static");
    }

    public TestPostConstruct() {
        System.out.println("construct");
    }

    @PostConstruct
    public void init() {
        System.out.println("PostConstruct");
    }

}

2.CommandLineRunner

package com.wlfy.www.teststartupsequence;

import org.springframework.boot.CommandLineRunner;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

/**
 * @author wl
 * @description TestCommandLineRunner
 * @date 2022/4/8 21:07
 */
@Order(2)
@Component
public class TestCommandLineRunner implements CommandLineRunner {
    @Override
    public void run(String... args) throws Exception {
        System.out.println("Order 2 : TestCommandLineRunner");
    }
}

3.ApplicationRunner

package com.wlfy.www.teststartupsequence;

import org.springframework.boot.ApplicationArguments;
import org.springframework.boot.ApplicationRunner;
import org.springframework.core.annotation.Order;
import org.springframework.stereotype.Component;

/**
 * @author wl
 * @description TestApplicationRunner
 * @date 2022/4/8 21:06
 */
@Component
@Order(1)
public class TestApplicationRunner implements ApplicationRunner {
    @Override
    public void run(ApplicationArguments args) throws Exception {
        System.out.println("order 1 : TestApplicationRunner");
    }
}

SpringBoot启动执行顺序：
static
construct
PostConstruct
order 1 : TestApplicationRunner
Order 2 : TestCommandLineRunner

总结
Spring应用启动过程中，肯定是要自动扫描有@Component注解的类，加载类并初始化对象进行自动注入。加载类时首先要执行static静态代码块中的代码，之后再初始化对象时会执行构造方法。最新 Spring Boot 面试题整理好了，点击Java面试库小程序在线刷题。

在对象注入完成后，调用带有@PostConstruct注解的方法。当容器启动成功后，再根据@Order注解的顺序调用CommandLineRunner和ApplicationRunner接口类中的run方法。

因此，加载顺序为static>constructer>@PostConstruct>CommandLineRunner和ApplicationRunner.