Spring boot With Embedded Tomcat

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Spring boot with Embedded Timcat 동작 원리

Jar 파일 boot 구조

• 일반적으로 Execuexecutable jar 는 META-INF의 MANIFEST.MF의 Main-Class를 실행

Jar / root

META-INF

MANIFEST.MF

Manifest-Version: 1.0
Created-By: Maven Jar Plugin 3.2.0
Build-Jdk-Spec: 11
Implementation-Title: xxxx-xxx-xxx
Implementation-Version: 0.0.1-SNAPSHOT
Main-Class: org.springframework.boot.loader.JarLauncher
Start-Class: com.xx.yyy.xxx.XxxxxWebfluxApplication
Spring-Boot-Version: 2.4.3
Spring-Boot-Classes: BOOT-INF/classes/
Spring-Boot-Lib: BOOT-INF/lib/
Spring-Boot-Classpath-Index: BOOT-INF/classpath.idx
Spring-Boot-Layers-Index: BOOT-INF/layers.idx

MANIFEST를 확인해보면 main 클래스를 org.springframework.boot.loader.JarLauncher 로 잡고있다.

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JarLauncher

• Launcher를 최종 구현한 클래스
• 이 Launcher를 통해서 context를 구성한다

Launcher Class

protected void launch(String[] args) throws Exception {
    JarFile.registerUrlProtocolHandler();
    ClassLoader classLoader = createClassLoader(getClassPathArchives());
    launch(args, getMainClass(), classLoader);
}

createClassLoader()

• 해당 메서드를 통해 LaunchedURLClassLoader를 생성하며 URLClassLoader를 상속 받으며, parent로 SystemClassLoader (AppClassLoader)를 갖는다