20.int16_t 转NSData(占四位) //bigEndian 传no +(NSData *) bytesFromInt16:(int)val bigEndian:(BOOL)bigEndian { char myByteArray[] = {0,0}; myByteArray[0]=val & 0xff; myByteArray[1]=(val>>8) & 0xff; if(bigEndian) { myByteArray[1]=val & 0xff; myByteArray[0]=(val...