反射机制——查找类接口

/**
 * 
 * @author king
 *
 * 查找类接口
 */
public class ClassUtils {

	public static List<Class> getAllClassByInterface(Class c) {//按照接口字母顺序查找

		List<Class> returnClassList = new ArrayList<Class>();

		if (c.isInterface()) {
			String packageName = c.getPackage().getName();
			try {
				try {
					List<Class> allClass = getClasses(packageName);

					for (int i = 0, len = allClass.size(); i < len; i++) {
						if (c.isAssignableFrom(allClass.get(i))) {
							if (!c.equals(allClass.get(i))) {
								returnClassList.add(allClass.get(i));
							}
						}
					}
				} catch (ClassNotFoundException e) {
					// TODO Auto-generated catch block
					e.printStackTrace();
				}
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		return returnClassList;

	}

	private static List<Class> getClasses(String packageName)
			throws IOException, ClassNotFoundException {

		ClassLoader classLoader = Thread.currentThread()
				.getContextClassLoader();
		String path = packageName.replace('.', '/');
		Enumeration<URL> resources = classLoader.getResources(path);
		List<File> dirs = new ArrayList<File>();

		while (resources.hasMoreElements()) {
			URL resource = resources.nextElement();
			dirs.add(new File(resource.getFile()));
		}
		ArrayList<Class> classes = new ArrayList<Class>();
		for (File directory : dirs) {
			classes.addAll(findClasses(directory, packageName));
		}
		return classes;
	}

	private static List<Class> findClasses(File directory, String packageName)
			throws ClassNotFoundException {
		List<Class> classes = new ArrayList<Class>();
		if (!directory.exists()) {
			return classes;

		}
		File[] files = directory.listFiles();
		for (File file : files) {
			if (file.isDirectory()) {
				assert !file.getName().contains(".");
				classes.addAll(findClasses(file,
						packageName + "." + file.getName()));

			} else if (file.getName().endsWith(".class")) {
				classes.add(Class.forName(packageName
						+ '.'
						+ file.getName().substring(0,
								file.getName().length() - 6)));
			}
		}
		return classes;
	}
}