核心程式碼：

    /***
     * 刪除指定資料夾下所有檔案
     *
     * @param path
     *            資料夾相對路徑
     * @return
     */
    public static boolean delAllFile(String path) {
        boolean flag = false;
        File file = new File(path);
        if (!file.exists()) {
            return flag;
        }
        if (!file.isDirectory()) {
            return flag;
        }
        String[] tempList = file.list();
        File temp = null;
        for (int i = 0; i < tempList.length; i++) {
            if (path.endsWith(File.separator)) {
                temp = new File(path + tempList[i]);
            } else {
                temp = new File(path + File.separator + tempList[i]);
            }
            if (temp.isFile()) {
                temp.delete();
            }
            if (temp.isDirectory()) {
                delAllFile(path + File.separator + tempList[i]);// 先刪除資料夾裡面的檔案
                delFolder(path + File.separator + tempList[i]);// 再刪除空資料夾
                flag = true;
            }
        }
        return flag;
    }

     /***
     * 刪除資料夾
     *
     * @param folderPath資料夾相對路徑
     */
    public static void delFolder(String folderPath) {
        try {
            delAllFile(folderPath); // 刪除完裡面所有內容
            String filePath = folderPath;
            filePath = filePath.toString();
            File myFilePath = new File(filePath);
            myFilePath.delete(); // 刪除空資料夾
        } catch (Exception e) {
            e.printStackTrace();
        }
    }