code: public static char[] long2char(long x)
      {
          char[] c = new char[4];
          c[0] = (char) (x >> 48);
          c[1] = (char) (x >> 32);
          c[2] = (char) (x >> 16);
          c[3] = (char) (x);
          return c;
      }
docs: 转换long型为char数组
  
  @param x