public static String fastUnicode(String str) {
		byte[] bytes = str.getBytes(Charsets.UTF_16);// 转为UTF-16字节数组
		int length = bytes.length;
		if (length > 2) {
			int i = 2;
			char[] chars = new char[(length - i) * 3];
			int index = 0;
			boolean isOdd = false;
			for (; i < length; i++) {
				if (isOdd = !isOdd) {
					chars[index++] = '\\';
					chars[index++] = 'u';
				}
				chars[index++] = digits[bytes[i] >> 4 & 0xf];
				chars[index++] = digits[bytes[i] & 0xf];
			}
			return new String(chars);
		} else {
			return "";
		}
	}