self.twoDimString = symbol.data;
    //编解码问题
    if ([self.twoDimString canBeConvertedToEncoding:NSShiftJISStringEncoding])
    {
        self.twoDimString = [NSString stringWithCString:[self.twoDimString cStringUsingEncoding: NSShiftJISStringEncoding] encoding:NSUTF8StringEncoding];
    }