基于@ComponentScan注解的使用详解

@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
@Documented
@Repeatable(ComponentScans.class)
public @interface ComponentScan {
   
   @AliasFor("basePackages")
   String[] value() default {};
   
   @AliasFor("value")
   String[] basePackages() default {};
   
   Class<?>[] basePackageClasses() default {};
   
   Class<? extends BeanNameGenerator> nameGenerator() default BeanNameGenerator.class;
   
   Class<? extends ScopeMetadataResolver> scopeResolver() default AnnotationScopeMetadataResolver.class;
   
   ScopedProxyMode scopedProxy() default ScopedProxyMode.DEFAULT;
   *.class"
    * 使用  includeFilters 和 excludeFilters 会更灵活
    */
   String resourcePattern() default ClassPathScanninGCandidateComponentProvider.DEFAULT_RESOURCE_PATTERN;
   
   boolean useDefaultFilters() default true;
   
   Filter[] includeFilters() default {};
   
   Filter[] excludeFilters() default {};
   
   boolean lazyInit() default false;
   
   @Retention(RetentionPolicy.RUNTIME)
   @Target({})
   @interface Filter {
      
      FilterType type() default FilterType.ANNOTATION;
      
      @AliasFor("classes")
      Class<?>[] value() default {};
      
      @AliasFor("value")
      Class<?>[] classes() default {};
      
      String[] pattern() default {};
   }
}

  <dependencies>
    <!-- https://mvnrepository.com/artifact/org.springframework/spring-context -->
		<dependency>
		    <groupId>org.springframework</groupId>
		    <artifactId>spring-context</artifactId>
		    <version>4.3.26.RELEASE</version>
		</dependency>
		<!-- Https://mvnrepository.com/artifact/junit/junit -->
		<dependency>
		  <groupId>junit</groupId>
			<artifactId>junit</artifactId>
			<version>4.12</version>
			<scope>test</scope>
		</dependency>	
  </dependencies>

public class iocTest {
	@Test
	public void test01() {
		//获取Spring的IOC容器
		ApplicationContext applicationContext=new AnnotationConfigApplicationContext(SpringConfig.class);
		//从容器中获取bean
	    String[] names= applicationContext.getBeanDefinitionNames();	
	       for(String i:names) {
	    	   System.out.println(i);
	       }
	}
}

@Configuration
@ComponentScan(basePackages = "com.learn",excludeFilters = {
  @Filter(type = FilterType.ANNOTATION,classes = {Controller.class,Service.class})
})
public class SpringConfig {
}

@Configuration
@ComponentScan(basePackages = "com.learn",includeFilters = {
  @Filter(type = FilterType.ANNOTATION,classes = {Controller.class,Service.class})
},useDefaultFilters = false)
public class SpringConfig {
}

public class MyTypeFilter implements TypeFilter {
    
	@Override
	public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory)
			throws IOException {
		// TODO Auto-generated method stub
	     //获取当前类注解的信息
        AnnotationMetadata annotationMetadata = metadataReader.getAnnotationMetadata();
        //获取当前正在扫描的类的类信息
        ClaSSMetadata classMetadata = metadataReader.getClassMetadata();
        //获取当前类资源（类的路径）
        Resource resource = metadataReader.getResource();
        String className = classMetadata.getClassName();
        if(className.contains("controller")){
            return true;
        }
        return false;
	}
}

@Configuration
@ComponentScan(basePackages = "com.learn",includeFilters = {
		@Filter(type = FilterType.ASSIGNABLE_TYPE,classes = {Person.class}),
		@Filter(type = FilterType.CUSTOM,classes = {MyTypeFilter.class}),
},useDefaultFilters = false)
public class SpringConfig {
}

//@Configuration
public class ProfileConfig {
    @Component("class1")
    private static class Class1 {
        @Bean
        public Class3 class3() {
            return new Class3();
        }
    }
    @Component("class2")
    static class Class2 {
    }
    //@Component("class3")
    protected static class Class3 {
    }
//    @Component("class4") //出错
//    protected class Class4 {
//
//    }
}
--------------------------------------------------------
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
//@Bean
public @interface MyBean {
    public static final int age1=3; //常量可以
    int age=2;
    public abstract String value() default "qwer"; //属性可以
    //内部类可以
    @Component
    @DependsOn("myBean.EventZ") //依赖事件bean的创建，保证该bean在事件bean之后创建
        //细节：因为是内部类，所以默认bean的id是类名首字母小写，不是eventZ而是myBean.EventZ
    class EventSource {
        public EventSource(){
            System.out.println("事件源创建了...");
        }
    }
    @Component//("eventZ")
    public static class EventZ {
        public EventZ(){
            System.out.println("事件创建了...");
        }
    }
}