复用代码系列：类扫描（基于Spring）

迷南。 2022-05-26 13:27 142阅读 0赞

[复用代码系列目录][Link 1]

package com.spring.custom_scanner;
    
    import java.io.IOException;
    import java.lang.annotation.Annotation;
    import java.util.HashSet;
    import java.util.LinkedList;
    import java.util.List;
    import java.util.Set;
    
    import org.springframework.beans.factory.BeanDefinitionStoreException;
    import org.springframework.context.ResourceLoaderAware;
    import org.springframework.core.io.Resource;
    import org.springframework.core.io.ResourceLoader;
    import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
    import org.springframework.core.io.support.ResourcePatternResolver;
    import org.springframework.core.io.support.ResourcePatternUtils;
    import org.springframework.core.type.classreading.CachingMetadataReaderFactory;
    import org.springframework.core.type.classreading.MetadataReader;
    import org.springframework.core.type.classreading.MetadataReaderFactory;
    import org.springframework.core.type.filter.AnnotationTypeFilter;
    import org.springframework.core.type.filter.TypeFilter;
    import org.springframework.util.SystemPropertyUtils;
    
    public class ClassScaner implements ResourceLoaderAware {
    
        private ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
    
        private final List<TypeFilter> includeFilters = new LinkedList<TypeFilter>();
    
        private final List<TypeFilter> excludeFilters = new LinkedList<TypeFilter>();
    
        private MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(this.resourcePatternResolver);
    
        public ClassScaner() {
    
        }
    
        public void setResourceLoader(ResourceLoader resourceLoader) {
            this.resourcePatternResolver = ResourcePatternUtils.getResourcePatternResolver(resourceLoader);
            this.metadataReaderFactory = new CachingMetadataReaderFactory( resourceLoader);
        }
    
        public final ResourceLoader getResourceLoader() {
            return this.resourcePatternResolver;
        }
    
        public void addIncludeFilter(TypeFilter includeFilter) {
            this.includeFilters.add(includeFilter);
        }
    
        public void addExcludeFilter(TypeFilter excludeFilter) {
            this.excludeFilters.add(0, excludeFilter);
        }
    
        public void resetFilters(boolean useDefaultFilters) {
            this.includeFilters.clear();
            this.excludeFilters.clear();
        }
    
        public static Set<Class> scan(String basePackage, Class<? extends Annotation>... annotations) {
            ClassScaner cs = new ClassScaner();
            for (Class anno : annotations)
                cs.addIncludeFilter(new AnnotationTypeFilter(anno));
            return cs.doScan(basePackage);
        }
    
        public static Set<Class> scan(String[] basePackages, Class<? extends Annotation>... annotations) {
            ClassScaner cs = new ClassScaner();
            for (Class anno : annotations)
                cs.addIncludeFilter(new AnnotationTypeFilter(anno));
            Set<Class> classes = new HashSet<Class>();
            for (String s : basePackages)
                classes.addAll(cs.doScan(s));
            return classes;
        }
    
        public Set<Class> doScan(String basePackage) {
            Set<Class> classes = new HashSet<Class>();
            try {
                String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX
                        + org.springframework.util.ClassUtils
                        .convertClassNameToResourcePath(SystemPropertyUtils
                                .resolvePlaceholders(basePackage))
                        + "/**/*.class";
                Resource[] resources = this.resourcePatternResolver.getResources(packageSearchPath);
    
                for (int i = 0; i < resources.length; i++) {
                    Resource resource = resources[i];
                    if (resource.isReadable()) {
                        MetadataReader metadataReader = this.metadataReaderFactory.getMetadataReader(resource);
                        if ((includeFilters.size() == 0 && excludeFilters.size() == 0)
                                || matches(metadataReader)) {
                            try {
                                classes.add(Class.forName(metadataReader.getClassMetadata().getClassName()));
                            } catch (ClassNotFoundException e) {
                                e.printStackTrace();
                            }
    
                        }
                    }
                }
            } catch (IOException ex) {
                throw new BeanDefinitionStoreException(
                        "I/O failure during classpath scanning", ex);
            }
            return classes;
        }
    
        protected boolean matches(MetadataReader metadataReader) throws IOException {
            for (TypeFilter tf : this.excludeFilters) {
                if (tf.match(metadataReader, this.metadataReaderFactory)) {
                    return false;
                }
            }
            for (TypeFilter tf : this.includeFilters) {
                if (tf.match(metadataReader, this.metadataReaderFactory)) {
                    return true;
                }
            }
            return false;
        }
    
    }

[Link 1]: https://blog.csdn.net/sunct/article/details/80175458