自定义 start 组件

方式一：Spring SPI

META-INF\spring.factories

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
  com.example.boot.serve.starter.AppConfig

方式二：

利用 @Import 注解，导入一个实现了 ImportSelector 接口的类，然后由这个类，完成 Configuration 的注册

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Import(SwitchLoggerImport.class)
public @interface EnableSwitchLogger {
}
public class SwitchLoggerImport implements ImportSelector {
    @Override
    public String[] selectImports(AnnotationMetadata annotationMetadata) {
        return new String[]{SwitchLoggerConfig.class.getName()};
    }
}

自动配置类

@Configuration
@Import({Heartbeat.class})
@ConditionalOnBean({ServeMarker.class})
@EnableConfigurationProperties({ServeProperties.class})
public class AppConfig {
    @Bean
    public ServeController serveController() {
        return new ServeController();
    }
    @Bean
    public ServletRegistrationBean<Servlet> servletRegistrationBean() {
        ServletRegistrationBean<Servlet> registrationBean = new ServletRegistrationBean();
        registrationBean.setServlet(new DispatcherRegisterServlet());
        registrationBean.addUrlMappings(new String[]{"*.do"});
        registrationBean.setLoadOnStartup(1);
        return registrationBean;
    }
}