SpringBean生命周期及類加載器簡述

Spring bean 從jvm加載class初使化至程序結束bean消亡全局流程大緻如下，同步的相關的簡單驗證

public class TestBean implements InitializingBean, DisposableBean {     public TestBean() {         System.out.println("1: constructor ----> 構造方法");     }     @PostConstruct     public void postConstruct()     {         System.out.println("3: @PostConstruct/postConstruct ");     @PreDestroy     public void PreDestroy()         System.out.println("7: @PreDestroy/PreDestroy ");     public void initMethod() {         System.out.println("5: initMethod指定的initMethod方法");     public void destroyMethod() {         System.out.println("9: destroyMethod指定的destroyMethod方法");     @Override     public void destroy() throws Exception {         System.out.println("8: DisposableBean/destroy");     public void afterPropertiesSet() throws Exception {         System.out.println("4: InitializingBean/afterPropertiesSet......"); } public class TestBeanPostPorcesser implements BeanPostProcessor {     @Override     public Object postProcessBeforeInitialization(Object bean, String beanName)         throws BeansException {         if(beanName.equals("testBean")) {             System.out.println("2: BeanPostProcessor/postProcessBeforeInitialization: " + beanName);         }         return bean;     }     @Override     public Object postProcessAfterInitialization(Object bean, String beanName)         throws BeansException {         if(beanName.equals("testBean")) {             System.out.println("6: BeanPostProcessor/postProcessAfterInitialization: " + beanName);         }         return bean;     } } @Configuration public class TestConfig {     @Bean(initMethod = "initMethod",destroyMethod = "destroyMethod")     public TestBean testBean() {         return new TestBean();     }     @Bean     public TestBeanPostPorcesser testBeanPostPorcesser() {         return new TestBeanPostPorcesser();     } } ******************************************************************** 1: constructor ----> 構造方法 2: BeanPostProcessor/postProcessBeforeInitialization: testBean 3: @PostConstruct/postConstruct 4: InitializingBean/afterPropertiesSet...... 5: initMethod指定的initMethod方法 6: BeanPostProcessor/postProcessAfterInitialization: testBean 2021-03-20 22:53:18.404  INFO 7492 --- [           main] o.s.s.concurrent.ThreadPoolTaskExecutor  : Shutting down ExecutorService 7: @PreDestroy/PreDestroy 8: DisposableBean/destroy 9: destroyMethod指定的destroyMethod方法 Process finished with exit code 130

類加載器

Ø  類加載器用來加載其他類,類加載器本身無需加載,嵌套在虛拟機上即 BootStrap

Ø  類加載器将類的位元組碼檔案從硬碟加載進記憶體

Ø  系統預設三個主要類加載器,每個類負責加載特定位置:  BootStrap, ExtClassLoader,AppClassLoade(SystemCLassLoade) 

Springboot Aware接口