NSData与Byte

[NSData bytes]返回的是Byte类型的，Byte是unsigned char,Byte可以是个数组，打印Byte需要遍历打印

Byte *byte = (Byte *)[cipher bytes];    for (int i = 0; i < [cipher length]; i ++) {        NSLog(@"data转字节byte = %d", byte[i]);    }

OC创建字节数组的方式

1.只读

［data bytes］；

2.需要编辑，并且关于data

NSUInteger length = [data length]; unsigned char *bytes = malloc( length * sizeof(unsigned char) ); ／／ 使用malloc创建字节数组[data getBytes:bytes length:length];／／ 将data中数据copy到字节数组中

或者

- (NSArray*) arrayOfBytesFromData:(NSData*) data {  

if (data.length > 0)      

  {   

<span style="white-space:pre"></span>NSMutableArray *array = [NSMutableArray arrayWithCapacity:data.length];   <span style="white-space:pre"></span>NSUInteger i = 0;   

<span style="white-space:pre"></span>for (i = 0; i < data.length; i++)   <span style="white-space:pre"></span>{

<span style="white-space:pre"></span>unsigned char byteFromArray = data.bytes[i];    <span style="white-space:pre"></span>[array addObject:[NSValue valueWithBytes:&byteFromArrayobjCType:@encode(unsigned char)]];  

 <span style="white-space:pre"></span>}   <span style="white-space:pre"></span>return [NSArray arrayWithArray:array];  

  }  return nil; 

}