SpringBoot 钩子接口的实现代码

@Component
@ToString
public class TestService  implements BeanNameAware, BeanClassLoaderAware {
    private String beanName;
    private ClassLoader classLoader;

    @Override
    public void setBeanClassLoader(ClassLoader classLoader) {
        this.classLoader = classLoader;
    }

    @Override
    public void setBeanName(String name) {
        this.beanName= name;
    }

}

@Component
public class TestBean implements InitializingBean, DisposableBean {

    // bean 设置完属性之后调用
    @Override
    public void afterPropertiesSet() throws Exception {
        // 初始化操作
        System.out.println("TestBean init");
    }

    // 销毁之后调用
    @Override
    public void destroy() throws Exception {
        // 释放资源
        System.out.println("TestBean destroy");
    }
}

@Component
public class TestPostProcessor implements BeanPostProcessor {

    @Override
    public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("Bean 初始化前");
        return bean;
    }

    @Override
    public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
        System.out.println("Bean 初始化后");
        return bean;
    }
}

@Component
public class TestFactoryPostProcessor implements BeanFactoryPostProcessor {
    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        System.out.println("所有 BeanDefinition 已被加载，但还未实例化 Bean");
        
        // 动态添加 BeanDefinition
        //转换为子类 DefaultListableBeanFactory
        DefaultListableBeanFactory defaultBeanFactory = 
            (DefaultListableBeanFactory) beanFactory;
        //new 一个 beanDefinition对象
        GenericBeanDefinition b = new GenericBeanDefinition();
        b.setBeanClass(Testbean.class);
        //添加一个 beanDefinition 对象
        defaultBeanFactory.registerBeanDefinition("testBean", b);
        
        // 动态获取 BeanDefinition
  Object o = defaultBeanFactory.getBean("testBean")
    }
}

public class TestImportSelector implements ImportSelector {
    @Override
    public String[] selectImports(AnnotationMetadata importingClassMetadata) {
        
        // AnnotationMetadata 存储注解元数据信息
        // 可以动态的返回需要被容器管理的类名称
        if (importingClassMetadata.hasAnnotation("")) {
            // 判断是否包含某个注解
        }
        
        // TestBean 加入到 Spring 容器中
        return new String[]{"com.example.pojo.TestBean"};
    }
}

@Configuration
@Import(TestImportSelector.class)
public class TestConfig {
}

public class TestRegistrar implements ImportBeanDefinitionRegistrar {
    @Override
    public void registerBeanDefinitions(AnnotationMetadata importingClassMetadata,
                                        BeanDefinitionRegistry registry) {
        GenericBeanDefinition b = new GenericBeanDefinition();
        b.setBeanClass(NotScanBean.class);
        b.setLazyInit(true);
        // 注册到容器中
        registry.registerBeanDefinition(NotScanBean.class.getName(), b);
    }
}

@Component
public class TestFactoryBean implements FactoryBean<TestBean> {
    @Override
    public TestBean getObject() throws Exception {

        // 对 Bean 进行配置
        // 如代理、修饰等

        return new TestBean();
    }

    @Override
    public Class<?> getObjectType() {
        return null;
    }
}

public class TestApplicationEvent extends ApplicationEvent {

    public TestApplicationEvent(Object source) {
        super(source);
    }

    public void hello(){
        System.out.println("Hello Word!");
    }
}

@Component
public class TestApplicationListener implements ApplicationListener {

    @Override
    public void onApplicationEvent(ApplicationEvent event) {
        if (event instanceof TestApplicationEvent) {
            TestApplicationEvent testApplicationEvent = (TestApplicationEvent) event;
            testApplicationEvent.hello();
        }
    }
}

@SpringBootTest
class DemoApplicationTests {

    @Autowired
    ApplicationContext applicationContext;

    @Test
    public void test() {
        applicationContext.publishEvent(new TestApplicationEvent(new DemoApplication()));
    }
}
// Hello Word!

@Component
public class MyApplicationRunner implements ApplicationRunner {

    @Override
    public void run(ApplicationArguments args) throws Exception {
        System.out.println("原始参数：" + Arrays.asList(args.getSourceArgs()));
        Set<String> keys = args.getOptionNames();
        for (String key : keys) {
            System.out.println("解析后的 key: [" + key + "]  value: " + args.getOptionValues(key));
        }
        System.out.println("无 OptionName 的参数： " + args.getNonOptionArgs());
    }
}
// 例：启动参数 --a=1 --b c
// 打印 =>
// 原始参数：[--a=1, --b, c]
// 解析后的 key: [a]  value: [1]
// 解析后的 key: [b]  value: []
// 无 OptionName 的参数： [c]