《读spring源码》6注解@ComponentScan的FilterType.CUSTOM 讲解 自定义过滤器

在@ComponentScan 注解FilterType.CUSTOM 如何使用：

package com.enjoy.cap2.MainConfiguer;


import com.enjoy.cap1.Person;
import com.enjoy.cap2.controller.OderController;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.context.annotation.FilterType;
import org.springframework.stereotype.Controller;
import org.springframework.stereotype.Service;

@Configuration
@ComponentScan(value = "com.enjoy.cap2",includeFilters  = {
            @ComponentScan.Filter(type = FilterType.CUSTOM,classes = {MYTyperFilter.class})
    },useDefaultFilters = false)//扫描组件
public class MainConfig {
    @Bean
    public Person person1(){
        return new Person("张三",22);
    }
}

package com.enjoy.cap2.MainConfiguer;

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 MYTyperFilter implements TypeFilter {
    private ClassMetadata classMetadata;
    /**
     *
     * MetadataReader 读取到当前正在扫描类的信息
     * MetadataReaderFactory 可以获取到其他任何类信息
     *
     * @param metadataReader
     * @param metadataReaderFactory
     * @return
     * @throws IOException
     */
    @Override
    public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory) throws IOException {
        //获取当前类注解的信息
        AnnotationMetadata annotationMetadata = metadataReader.getAnnotationMetadata();
        //获取当前正在扫描的类信息
        this.classMetadata = metadataReader.getClassMetadata();
        //获取当前类资源（类的路径）
        Resource resource = metadataReader.getResource();

        String className = classMetadata.getClassName();
        System.out.println("===============>"+className);

        return false;
    }
}

打印结果

修改代码加上 if满足条件返回true的情况打印结果如下：

package com.enjoy.cap2.MainConfiguer;

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 MYTyperFilter implements TypeFilter {
    private ClassMetadata classMetadata;
    /**
     *
     * MetadataReader 读取到当前正在扫描类的信息
     * MetadataReaderFactory 可以获取到其他任何类信息
     *
     * @param metadataReader
     * @param metadataReaderFactory
     * @return
     * @throws IOException
     */
    @Override
    public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory) throws IOException {
        //获取当前类注解的信息
        AnnotationMetadata annotationMetadata = metadataReader.getAnnotationMetadata();
        //获取当前正在扫描的类信息
        this.classMetadata = metadataReader.getClassMetadata();
        //获取当前类资源（类的路径）
        Resource resource = metadataReader.getResource();

        String className = classMetadata.getClassName();
        System.out.println("===============>"+className);
        if(className.contains("er")){
            return true;
        }
        return false;
    }
}

对容器中的对象加载做了一个过滤的操作