objective-c NSData,Int互转

将int转成NSData

    NSString *temp=@"test";        NSData *datatemp =[temp dataUsingEncoding:NSUTF8StringEncoding];        int datatemplength =CFSwapInt32BigToHost((uint32_t)datatemp.length);  //大小端不一样，需要转化        NSData *data = [NSData dataWithBytes: &datatemplength length: sizeof(datatemplength)];        NSMutableData *result=[[NSMutableData alloc]init];        [result appendData:data];    [result appendData:datatemp];

将NSData转成int

    int datalength;        [result getBytes: &datalength length: sizeof(datalength)];        int length=CFSwapInt32BigToHost(datalength);        NSData *databack = [result subdataWithRange:NSMakeRange(4, length)];