// 声明：此乃原创，转载注明author

//author：胡名海

//// 从字节数组到十六进制字符串转换
 public static String Bytes2HexString(byte[] b) {
  if(b==null){
   return null;
  }
  byte[] buff = new byte[2 * b.length];//[2 * b.length]
  for (int i = 0; i < b.length; i++) {
   buff[2 * i] = hex[(b[i] >> 4) & 0x0f];
   buff[2 * i + 1] = hex[b[i] & 0x0f];
  }
  return new String(buff);
 }

// 从十六进制字符串到字节数组转换
 public static byte[] HexString2Bytes(String hexstr) {
  byte[] b = new byte[hexstr.length() / 2];
  int j = 0;
  for (int i = 0; i < b.length; i++) {
   char c0 = hexstr.charAt(j++);
   char c1 = hexstr.charAt(j++);
   b[i] = (byte) ((parse(c0) << 4) | parse(c1));
  }
  return b;
 }