1. NSString转化为UNICODE String:(NSString*)fname = @“Test”; char fnameStr[10];memcpy(fnameStr, [fname cStringUsingEncoding:NSUnicodeStringEncoding], 2*([fname length]));2. NSString转化为char(NSString*)fname = @“Test”;char fnameStr[10];fnameStr =[fname UTF8String];3. char -> NSData: 方法一: char * postData = "TEST"; NSData *data = [NSData dataWithBytes:postData length:strlen(postData)]; 方法二: 转换为NSString: - (id)initWithUTF8String:(const char *)bytes 然后用NSString的 - (NSData *)dataUsingEncoding:(NSStringEncoding)encoding4. NSData ->char NSData returnData ; char* bu=[returnData bytes];5. NSData->NSString NSString* aStr; aStr = [NSString alloc] initWithData:aData encoding:NSASCIIStringEncoding];6. NSString->NSData NSData* aData; aData = [aStr dataUsingEncoding: NSASCIIStringEncoding];