扫描给定包及子包内的所有类

import java.io.File;
import java.io.IOException;
import java.net.URL;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;

/**
 * 
 * <p>
 * Title: PackageUtils.java
 * </p>
 * <p>
 * E-Mail: [e-mail]
 * </p>
 * <p>
 * QQ: 176291935
 * </p>
 * <p>
 * Http: iaiai.iteye.com
 * </p>
 * <p>
 * Create time: 2011-8-2
 * </p>
 * 
 * @author 丸子
 * @version 0.0.1
 */
public class PackageUtils {

	/**
	 * 扫描给定包及子包内的所有类
	 * 
	 * @param packageName
	 *            给定的包名
	 * @return The classes
	 * @throws ClassNotFoundException
	 * @throws IOException
	 */
	private static Class[] getClasses(String packageName)
			throws ClassNotFoundException, IOException {
		Class cla = PackageUtils.class;
		String path = packageName.replace('.', '/');
		Enumeration<URL> resources = cla.getClassLoader().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.toArray(new Class[classes.size()]);
	}

	/**
	 * 找到制定包内的所有class文件
	 * 
	 * @param directory
	 *            目录名称
	 * @param packageName
	 *            包名称
	 * @return The classes
	 * @throws ClassNotFoundException
	 */
	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()) {
				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;
	}

	/**
	 * @throws IOException
	 * @throws ClassNotFoundException
	 * 
	 */
	public static void main(String[] args) throws Exception {
		Class[] clas = PackageUtils.getClasses("org");
		for (Class cla : clas) {
			System.out.println(cla.getName());
		}
	}

}