如何从类路径中读取Java包中的所有类? [英] How do I read all classes from a Java package in the classpath?
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问题描述
我需要读取Java包中包含的类。这些类在classpath中。我需要直接从Java程序执行此任务。你知道一个简单的方法吗?
I need to read classes contained in a Java package. Those classes are in classpath. I need to do this task from a Java program directly. Do you know a simple way to do?
List<Class> classes = readClassesFrom("my.package")
推荐答案
如果您在类路径中有 Spring ,然后以下内容将会执行此操作。
If you have Spring in you classpath then the following will do it.
查找使用XmlRootElement注释的包中的所有类:
Find all classes in a package that are annotated with XmlRootElement:
private List<Class> findMyTypes(String basePackage) throws IOException, ClassNotFoundException
{
ResourcePatternResolver resourcePatternResolver = new PathMatchingResourcePatternResolver();
MetadataReaderFactory metadataReaderFactory = new CachingMetadataReaderFactory(resourcePatternResolver);
List<Class> candidates = new ArrayList<Class>();
String packageSearchPath = ResourcePatternResolver.CLASSPATH_ALL_URL_PREFIX +
resolveBasePackage(basePackage) + "/" + "**/*.class";
Resource[] resources = resourcePatternResolver.getResources(packageSearchPath);
for (Resource resource : resources) {
if (resource.isReadable()) {
MetadataReader metadataReader = metadataReaderFactory.getMetadataReader(resource);
if (isCandidate(metadataReader)) {
candidates.add(Class.forName(metadataReader.getClassMetadata().getClassName()));
}
}
}
return candidates;
}
private String resolveBasePackage(String basePackage) {
return ClassUtils.convertClassNameToResourcePath(SystemPropertyUtils.resolvePlaceholders(basePackage));
}
private boolean isCandidate(MetadataReader metadataReader) throws ClassNotFoundException
{
try {
Class c = Class.forName(metadataReader.getClassMetadata().getClassName());
if (c.getAnnotation(XmlRootElement.class) != null) {
return true;
}
}
catch(Throwable e){
}
return false;
}
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