谷歌反射，如果你也想发现接口。

Spring ClassPathScanningCandidateComponentProvider没有发现接口。

You can find classes with any given annotation with ClassGraph, as well as searching for other criteria of interest, e.g. classes that implement a given interface. (Disclaimer, I am the author of ClassGraph.) ClassGraph can build an abstract representation of the entire class graph (all classes, annotations, methods, method parameters, and fields) in memory, for all classes on the classpath, or for classes in whitelisted packages, and you can query that class graph however you want. ClassGraph supports more classpath specification mechanisms and classloaders than any other scanner, and also works seamlessly with the new JPMS module system, so if you base your code on ClassGraph, your code will be maximally portable. See the API here.

如果你正在寻找一个替代反射，我想推荐Panda Utilities - AnnotationsScanner。这是一个基于反射库源代码的无Guava (Guava有~3MB, Panda Utilities有~200kb)扫描仪。

它还专门用于基于未来的搜索。如果你想扫描多次包含的源，或者甚至提供一个API，允许某人扫描当前的类路径，AnnotationsScannerProcess会缓存所有获取的类文件，所以它真的很快。

AnnotationsScanner使用的简单示例:

AnnotationsScanner scanner = AnnotationsScanner.createScanner()
        .includeSources(ExampleApplication.class)
        .build();

AnnotationsScannerProcess process = scanner.createWorker()
        .addDefaultProjectFilters("net.dzikoysk")
        .fetch();

Set<Class<?>> classes = process.createSelector()
        .selectTypesAnnotatedWith(AnnotationTest.class);

Spring有一个AnnotatedTypeScanner类。 这个类内部使用

ClassPathScanningCandidateComponentProvider

该类具有实际扫描类路径资源的代码。它通过使用运行时可用的类元数据来实现这一点。

可以简单地扩展这个类或使用相同的类进行扫描。下面是构造函数定义。

/**
     * Creates a new {@link AnnotatedTypeScanner} for the given annotation types.
     * 
     * @param considerInterfaces whether to consider interfaces as well.
     * @param annotationTypes the annotations to scan for.
     */
    public AnnotatedTypeScanner(boolean considerInterfaces, Class<? extends Annotation>... annotationTypes) {

        this.annotationTypess = Arrays.asList(annotationTypes);
        this.considerInterfaces = considerInterfaces;
    }

在Spring中，您还可以使用AnnotationUtils类编写以下代码。例如:

Class<?> clazz = AnnotationUtils.findAnnotationDeclaringClass(Target.class, null);

要了解更多细节和所有不同的方法，请查看官方文档: https://docs.spring.io/spring/docs/current/javadoc-api/org/springframework/core/annotation/AnnotationUtils.html

Classloader API没有“枚举”方法，因为类加载是一个“按需”活动——在类路径中通常有数千个类，其中只有一小部分是需要的(目前仅rt.jar就有48MB !)

因此，即使您可以枚举所有的类，这也会非常耗费时间和内存。

简单的方法是在设置文件(xml或任何适合你的文件)中列出相关的类;如果您希望自动执行此操作，请将自己限制在一个JAR或一个类目录中。