public class ClassUtils {

    private static final Logger LOGGER  = LoggerFactory.getLogger(ClassUtils.class);

    /**

     * 返回某个父类底下所有的实现类

     */public static List<Class> getSubClassesByParentClass(Class parentClass) {

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

        String packageName = parentClass.getPackage().getName();

        try {

            List<Class> allClass = getClassesByPackageName(packageName);

            for (int i = 0; i < allClass.size(); i++) {

                if (parentClass.isAssignableFrom(allClass.get(i))) {

                    if (!parentClass.equals(allClass.get(i))) {

                        returnClassList.add(allClass.get(i));

                    }

                }

            }

        } catch (Exception e) {

            LOGGER.error(e.getMessage(), e);

        }

        return returnClassList;

    }

    /**

     * 从一个包中查找出所有类,在jar包中不能查找

     *

     * @param packageName

     * @return

     * @throws IOException

     * @throws ClassNotFoundException

     */

    public static List<Class> getClassesByPackageName(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;

    }

    /**

     *

     * @param directory

     * @param packageName

     * @return

     * @throws ClassNotFoundException

     */

    public 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;

    }

    /**

     * 对Map类型数据按Key排序

     *

     * @param map

     */public static List sort(Map map) {

        List list = new ArrayList(map.keySet());

        Collections.sort(list, new Comparator() {

            public int compare(Object a, Object b) {

                return a.toString().toLowerCase().compareTo(

                        b.toString().toLowerCase());

            }

        });

        return list;

    }

}