我怎样才能找到具有自定义注解@foo所有豆？ [英] How can I find all beans with the custom annotation @Foo?

问题描述

我有这个春天的配置：

@Lazy
@Configuration
public class MyAppConfig {
    @Foo @Bean
    public IFooService service1() { return new SpecialFooServiceImpl(); }
}

我怎样才能被标注了 @foo ？

请注意： @foo 是我定义的自定义注释。这不是官春注解之一。

Note: @Foo is a custom annotation defined by me. It's not one of the "official" Spring annotations.

以下阿维纳什T的建议，我写了这个测试用例：

Following the suggestions of Avinash T., I wrote this test case:

import static org.junit.Assert.*;
import java.lang.annotation.ElementType;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import java.lang.annotation.Retention;
import java.lang.reflect.Method;
import java.util.Map;
import org.junit.Test;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.Lazy;

public class CustomAnnotationsTest {

    @Test
    public void testFindByAnnotation() throws Exception {

        AnnotationConfigApplicationContext appContext = new AnnotationConfigApplicationContext( CustomAnnotationsSpringCfg.class );

        Method m = CustomAnnotationsSpringCfg.class.getMethod( "a" );
        assertNotNull( m );
        assertNotNull( m.getAnnotation( Foo.class ) );

        BeanDefinition bdf = appContext.getBeanFactory().getBeanDefinition( "a" );
        // Is there a way to list all annotations of bdf?

        Map<String, Object> beans = appContext.getBeansWithAnnotation( Foo.class );
        assertEquals( "[a]", beans.keySet().toString() );
    }


    @Retention( RetentionPolicy.RUNTIME )
    @Target( ElementType.METHOD )
    public static @interface Foo {

    }

    public static class Named {
        private final String name;

        public Named( String name ) {
            this.name = name;
        }

        @Override
        public String toString() {
            return name;
        }
    }

    @Lazy
    @Configuration
    public static class CustomAnnotationsSpringCfg {

        @Foo @Bean public Named a() { return new Named( "a" ); }
             @Bean public Named b() { return new Named( "b" ); }
    }
}

但它失败， org.junit.ComparisonFailure：预期：其中，[A]]＆GT;但：其中，[[]]＆GT; 。为什么呢？

推荐答案

一对夫妇春天专家的帮助下，我找到了一个解决方案：源的属性的BeanDefinition 可 StandardMethodMetadata 。这个类有一个方法 getAnnotationAttributes（），我可以用它来获取bean方法的注释：

With the help of a couple of Spring experts, I found a solution: The source property of a BeanDefinition can be StandardMethodMetadata. This class has a method getAnnotationAttributes() which I can use to get the annotations of a bean method:

public List<String> getBeansWithAnnotation( Class<? extends Annotation> type, Predicate<Map<String, Object>> attributeFilter ) {

    List<String> result = Lists.newArrayList();

    ConfigurableListableBeanFactory factory = applicationContext.getBeanFactory();
    for( String name : factory.getBeanDefinitionNames() ) {
        BeanDefinition bd = factory.getBeanDefinition( name );

        if( bd.getSource() instanceof StandardMethodMetadata ) {
            StandardMethodMetadata metadata = (StandardMethodMetadata) bd.getSource();

            Map<String, Object> attributes = metadata.getAnnotationAttributes( type.getName() );
            if( null == attributes ) {
                continue;
            }

            if( attributeFilter.apply( attributes ) ) {
                result.add( name );
            }
        }
    }

    return result;
}

依据与辅助类和测试用例的全部code

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