SpringBoot启动执行顺序

1.static、construct、PostConstructpackagecom.wlfy.www.teststartupsequence;importorg.springframework.stereotype.Component;importjavax.annotation.PostConstruct;/**
 * @author wl
 * @description TestPostConstruct
 * @date 2022/4/8 21:01
 */@ComponentpublicclassTestPostConstruct{static{System.out.println("static");}publicTestPostConstruct(){System.out.println("construct");}@PostConstructpublicvoidinit(){System.out.println("PostConstruct");}}

2.CommandLineRunner

packagecom.wlfy.www.teststartupsequence;importorg.springframework.boot.CommandLineRunner;importorg.springframework.core.annotation.Order;importorg.springframework.stereotype.Component;/**
 * @author wl
 * @description TestCommandLineRunner
 * @date 2022/4/8 21:07
 */@Order(2)@ComponentpublicclassTestCommandLineRunnerimplementsCommandLineRunner{@Overridepublicvoidrun(String... args)throwsException{System.out.println("Order 2 : TestCommandLineRunner");}}

3.ApplicationRunner

packagecom.wlfy.www.teststartupsequence;importorg.springframework.boot.ApplicationArguments;importorg.springframework.boot.ApplicationRunner;importorg.springframework.core.annotation.Order;importorg.springframework.stereotype.Component;/**
 * @author wl
 * @description TestApplicationRunner
 * @date 2022/4/8 21:06
 */@Component@Order(1)publicclassTestApplicationRunnerimplementsApplicationRunner{@Overridepublicvoidrun(ApplicationArguments args)throwsException{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.