利用spring-core掃描指定包下面的類

import org.springframework.core.io.Resource;
import org.springframework.core.io.support.PathMatchingResourcePatternResolver;
import org.springframework.core.io.support.ResourcePatternResolver;
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.classreading.SimpleMetadataReaderFactory;
import org.springframework.util.ClassUtils;
import org.springframework.util.SystemPropertyUtils;

import java.util.HashSet;
import java.util.Set;
import java.util.stream.Collectors;

public class ScanUtils {

    private static final ResourcePatternResolver RESOLVER = new PathMatchingResourcePatternResolver();
    private static final MetadataReaderFactory METADATA_READER_FACTORY = new SimpleMetadataReaderFactory();

    /**
     * 掃描指定路徑下的所有類
     *
     * @param scanPath     掃描路徑
     * @param mustConcrete 掃描的類是否是具體的類，即非接口、非抽象類
     * @return 掃描到的類
     */
    public static Set<Class<?>> scanClass(String scanPath, boolean mustConcrete) {
        String path = ClassUtils.convertClassNameToResourcePath(SystemPropertyUtils.resolvePlaceholders(scanPath));
        String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX + path + "/**/*.class";

        Set<Class<?>> classes = new HashSet<>();
        try {
            Resource[] resources = RESOLVER.getResources(packageSearchPath);
            for (Resource resource : resources) {
                if (resource.isReadable()) {
                    MetadataReader metadataReader = METADATA_READER_FACTORY.getMetadataReader(resource);
                    ClassMetadata classMetadata = metadataReader.getClassMetadata();
                    if (!mustConcrete || classMetadata.isConcrete()) {
                        classes.add(Class.forName(classMetadata.getClassName()));
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
        return classes;
    }

    /**
     * 掃描指定路徑下指定超類的所有子類
     *
     * @param scanPath     掃描路徑
     * @param superclass   掃描的類的父類
     * @param mustConcrete 掃描的類是否是具體的類，即非接口、非抽象類
     * @return 掃描到的類
     */
    public static Set<Class<?>> scanSubclass(String scanPath, Class<?> superclass, boolean mustConcrete) {
        Set<Class<?>> scanClass = scanClass(scanPath, mustConcrete);
        return scanClass.stream().filter(superclass::isAssignableFrom).collect(Collectors.toSet());
    }

}