UTF-16系列文件的文件头信息，及相关去头处理

在带文件头的UTF-16系列文件中：(文件前三个字节是文件头)

UTF-16       0xfe   0xff   0xfe
UTF-16LE    0xff   0xfe  0x2d
UTF-16BE    0xfe  0xff   0x4e

对于带有UTF-16系列文件头的字符串去除文件头的处理方法如下：

    public static String removeUTFSignature(String strKey, String encoding) throws IOException {
        String resultKey = strKey;
        int index = 0;
        int[] utfHeader = new int[3];
        switch (encoding) {
        case "UTF-16LE":
            utfHeader[0] = 0xff;
            utfHeader[1] = 0xfe;
            utfHeader[2] = 0x2d;
            break;
        case "UTF-16BE":
            utfHeader[0] = 0xfe;
            utfHeader[1] = 0xff;
            utfHeader[2] = 0x4e;            
            break;
        case "UTF-16":
            utfHeader[0] = 0xfe;
            utfHeader[1] = 0xff;
            utfHeader[2] = 0xfe;
            break;
        default:
            // UTF-8
            utfHeader[0] = 0xef;
            utfHeader[1] = 0xbb;
            utfHeader[2] = 0xbf;            
            break;
        }
        DataInputStream dis = new DataInputStream(new ByteArrayInputStream(strKey.getBytes()));
        while (true) {
            int bb1 = dis.read();
            int bb2 = dis.read();
            int bb3 = dis.read();
            if (bb1 == utfHeader[0] && bb2 == utfHeader[1] && bb3 == utfHeader[2]) {
                index += 3;
            } else {
                break;
            }
        }

        resultKey = new String(strKey.getBytes(), index, strKey.getBytes().length - index);
        return resultKey;
    }