GBK,UTF8

GBK格式

NSStringEncodingenc =CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);

NSString*before =@"aaaaaaaaaa";

NSData* beforeData = [beforedataUsingEncoding:enc];

UTF8

NSData*pinUTF8Data=[@"aaaa"dataUsingEncoding:NSUTF8StringEncoding];