Spring - @CompentScan全解

小小工匠

发布于 2021-08-17 17:00:54

4580

基本使用

在配置类上写@CompentScan注解来进行包扫描

@Configuration
@ComponentScan(basePackages = {"com.artisan"})
public class MainConfig {

}

excludeFilters

@Configuration
@ComponentScan(basePackages = {"com.artisan"},excludeFilters = {
        @ComponentScan.Filter(type = FilterType.ANNOTATION,value = {Controller.class}),
        @ComponentScan.Filter(type = FilterType.ASSIGNABLE_TYPE,value = {ArtisanService.class})
})
public class MainConfig {
}

这里会排除标注了@Controller注解和特定的ArtisanService ,不会被加载到IOC容器中。

includeFilters

若使用包含的用法，需要把useDefaultFilters属性设置为false（true表示扫描全部的）

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

@ComponentScan.Filter

4种类型

自定义FilterType

import org.springframework.core.io.Resource;
import org.springframework.core.type.AnnotationMetadata;
import org.springframework.core.type.ClassMetadata;
import org.springframework.core.type.classreading.MetadataReader;
import org.springframework.core.type.classreading.MetadataReaderFactory;
import org.springframework.core.type.filter.TypeFilter;

import java.io.IOException;

 
public class ArtisanFilterType implements TypeFilter {

    @Override
    public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory) throws IOException {
        //获取当前类的注解源信息
        AnnotationMetadata annotationMetadata = metadataReader.getAnnotationMetadata();

        //获取当前类的class的源信息
        ClassMetadata classMetadata = metadataReader.getClassMetadata();
        //获取当前类的资源信息
        Resource resource =  metadataReader.getResource();
        System.out.println("类的路径:"+classMetadata.getClassName());
        if(classMetadata.getClassName().contains("dao")) {
            return true;
        }
        return false;
    }
}

引用自定义类型的Filter

@ComponentScan(basePackages = {"com.tuling.testcompentscan"},excludeFilters = { 
        @ComponentScan.Filter(type = FilterType.CUSTOM,value = ArtisanFilterType.class)
},includeFilters = {
        @ComponentScan.Filter(type = FilterType.ANNOTATION,value = Repository.class)
})

测试的话，打印下beanDefinition 即可

public class MainClass {

    public static void main(String[] args) {
        AnnotationConfigApplicationContext ctx = new AnnotationConfigApplicationContext(MainConfig.class);
        String[] beanDefinationNames = ctx.getBeanDefinitionNames();
        for (String name:beanDefinationNames) {
            System.out.println("bean的定义信息:"+name);
        }

    }
}

本文参与腾讯云自媒体同步曝光计划，分享自作者个人站点/博客。

原始发表：2021/04/03 ，如有侵权请联系 cloudcommunity@tencent.com 删除

容器