// 第一种

NSString *connID = ((Collector *)weakSelf.globalMutableArray[i]).orignalConnID;

                    const uint8_t a = [[connID substringToIndex:] intValue];

                    NSRange bRange = {, };

                    const uint8_t b = [[connID substringWithRange:bRange] intValue];

                    NSRange cRange = {, };

                    const uint8_t c = [[connID substringWithRange:cRange] intValue];

                    const uint8_t d = [[connID substringFromIndex:] intValue];

   //第二种

                    NSString *str = @"AA21f0c1762a3abc299c013abe7dbcc50001DD";

                    NSData* bytes = [str dataUsingEncoding:NSUTF8StringEncoding];

                    Byte * myByte = (Byte *)[bytes bytes];

                    NSLog(@"myByte = %hhu",myByte[]);

                    NSMutableData* data = [NSMutableData data];

                    NSScanner* scanner = [NSScanner scannerWithString:@"AA"];

                    unsigned intValue;

                    [scanner scanHexInt:&intValue];

                    [data appendBytes:&intValue length:];

                    Byte * yte = (Byte *)[data bytes];

                    // 拿到的数据

                    const uint8_t senddata[] = {0xEB, 0x90, 0x00, 0x05, 0x06, a, b, c, d, 0x87};