遞歸刪除目錄下的所有文件及子目錄下所有文件

/**
     * 遞歸刪除目錄下的所有文件及子目錄下所有文件
     * @param dir 將要刪除的文件目錄
     * @return boolean Returns "true" if all deletions were successful.
     *                 If a deletion fails, the method stops attempting to
     *                 delete and returns "false".
     */
    public static boolean deleteDir(File dir) {
        if (dir.isDirectory()) {
            String[] children = dir.list();
            //遞歸刪除目錄中的子目錄下
            for (int i=0; i<children.length; i++) {
                boolean success = deleteDir(new File(dir, children[i]));
                if (!success) {
                    return false;
                }
            }
        }
      
        return dir.delete();
    }