iOS中NSString和NSData的相互转化

NSString 转换成NSData 对象 

NSData* xmlData = [@"testdata" dataUsingEncoding:NSUTF8StringEncoding]; 

NSData 转换成NSString对象 

NSData * data; NSString *result = [[NSString alloc] initWithData:data  encoding:NSUTF8StringEncoding]; 

NSData 转换成char* 

NSData *data; char *test=[data bytes]; 

char* 转换成NSData对象 

byte* data = malloc(sizeof(byte)*16); NSData *content=[NSData dataWithBytes:data length:16];