*
     * @param buf
     *            追加先の文字列
     * @param i
     *            数値
     */
    public static void appendHex(final StringBuilder buf, final int i) {
        buf.append(Integer.toHexString(i >> 24 & 0xff));
        buf.append(Integer.toHexString(i >> 16 & 0xff));
        buf.append(Integer.toHexString(i >> 8 & 0xff));
        buf.append(Integer.toHexString(i & 0xff));
    }

    /**