Spring学习 - 自定义Spring 的 bean扫描器

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Component
public @interface MyAnno {

    @AliasFor(annotation = Component.class)
    String value() default "empty name";
}

public class CustomScanner extends ClassPathBeanDefinitionScanner {

    private Class<? extends Annotation> annoType;

    public CustomScanner(BeanDefinitionRegistry registry, Class<? extends Annotation> annoType) {
        super(registry);
        this.annoType = annoType;

        super.addIncludeFilter(new AnnotationTypeFilter(annoType));
    }

    @Override
    public int scan(String... basePackages) {
        return super.scan(basePackages);
    }
}

package cn.followtry.boot.java.service;

@MyAnno(value = "my_first_test_scanner_service")
public class MyService {
}

package cn.followtry.boot.java.test;

public class ScannerTest {

    /**  */
    private static final String BASE_PACKAGE = "cn.followtry.boot.java.service";

    /**
     * main.
     */
    public static void main(String[] args) {

        GenericApplicationContext applicationContext = new AnnotationConfigApplicationContext();

        CustomScanner scanner = new CustomScanner(applicationContext, MyAnno.class);
        int scanCount = scanner.scan(BASE_PACKAGE);
        System.out.println("1扫描的数量"+scanCount);
        applicationContext.refresh();
        String[] beanDefinitionNames = applicationContext.getBeanDefinitionNames();
        for (String beanDefinitionName : beanDefinitionNames) {
            System.out.println("bean name : " + beanDefinitionName);
        }

    }
}

public class ScannerConfiguration implements BeanDefinitionRegistryPostProcessor, InitializingBean, ApplicationContextAware, BeanNameAware {

    private static final Logger log = LoggerFactory.getLogger(ScannerConfiguration.class);

    private String basePackage;

    /**  */
    private String beanName;

    private ApplicationContext applicationContext;

    @Override
    public void afterPropertiesSet() throws Exception {
        log.info("======初始化自定义的配置:{},basePackage : {}", this.getClass().getCanonicalName(), this.basePackage);
    }

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

    @Override
    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
        log.info("=====开始启动自定义的扫描器扫描自定义的注解====");
        CustomScanner customScanner = new CustomScanner(registry, MyAnno.class);
        customScanner.scan(StringUtils.tokenizeToStringArray(this.basePackage, ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS));
        log.info("=====完成启动自定义的扫描器扫描自定义的注解====");
    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
        // left intentionally blank
    }

    @Override
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext = applicationContext;
    }

    public ApplicationContext getApplicationContext() {
        return applicationContext;
    }

    public String getBasePackage() {
        return basePackage;
    }

    public void setBasePackage(String basePackage) {
        this.basePackage = basePackage;
    }

    public String getBeanName() {
        return beanName;
    }
}

public class ScannerPostProcessor implements BeanDefinitionRegistryPostProcessor, EnvironmentAware, BeanFactoryAware {

    private static final Logger log = LoggerFactory.getLogger(ScannerPostProcessor.class);
    private ConfigurableEnvironment environment;
    private ConfigurableBeanFactory beanFactory;

    @Override
    public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
        this.beanFactory = (ConfigurableBeanFactory)beanFactory;
    }

    @Override
    public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException {
        //将配置的 kv 绑定到指定的对象上
        MyBootScanProperties scanProperties = Binder.get(this.environment).bind("my-scanner", Bindable.of(MyBootScanProperties.class)).orElse(new MyBootScanProperties());
        BeanDefinition beanDefinition = this.buildScannerConfigurerBeanDefinition(scanProperties);
        //注册对象
        registry.registerBeanDefinition("scannerConfiguration",beanDefinition);

    }

    @Override
    public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
    }

    @Override
    public void setEnvironment(Environment environment) {
        this.environment = (ConfigurableEnvironment)environment;
    }

    private BeanDefinition buildScannerConfigurerBeanDefinition(MyBootScanProperties myBootScanProperties) {
        BeanDefinitionBuilder scannerConfigurerBuilder = BeanDefinitionBuilder.genericBeanDefinition(ScannerConfiguration.class);
        scannerConfigurerBuilder.addPropertyValue("basePackage", myBootScanProperties.getBasePackage());
        return scannerConfigurerBuilder.getBeanDefinition();
    }
}

@Configuration
@ConditionalOnProperty(
        name = {"mdp.zebra.enabled"},
        matchIfMissing = true
)
public class ScanAutoConfiguration {

    @Bean
    public ScannerPostProcessor myScannerPostProcessor(){
        return new ScannerPostProcessor();
    }
}

@ConfigurationProperties(
        prefix = "my-scanner"
)
public class MyBootScanProperties {
    public static final String MY_BOOT_PREFIX = "my-scanner";

    /**  */
    private String basePackage = ".";

    public String getBasePackage() {
        return basePackage;
    }

    public void setBasePackage(String basePackage) {
        this.basePackage = basePackage;
    }
}