一、json解析出错误？
1. 编码问题。

2. 如果data是有数据的，但是arr是nil，找到error:The operation couldn't be completed. (Cocoa error 3840.)NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:urlString]];NSError *error = nil;NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);NSString *dataString = [[NSString alloc] initWithData:data encoding:enc];NSData *utf8Data = [dataString dataUsingEncoding:NSUTF8StringEncoding];NSArray *arr = [NSJSONSerialization JSONObjectWithData:utf8Data options:NSJSONReadingMutableContainers error:&error];

3. json非标准格式：（比如json数据存在\\n \

\ 等制表符）

NSData *data = [NSData dataWithContentsOfURL:[NSURL URLWithString:urlString]];

NSError *error = nil;NSStringEncoding enc = CFStringConvertEncodingToNSStringEncoding(kCFStringEncodingGB_18030_2000);NSString *dataString = [[NSString alloc] initWithData:data encoding:enc];//json数据当中没有 \\n \

\ 等制表符，当后台给出有问题时，我们需要对json数据过滤 dataString = [dataString stringByReplacingOccurrencesOfString:@\"\

\\n\" withString:@\"\"]; dataString = [dataString stringByReplacingOccurrencesOfString:@\"\\n\" withString:@\"\"]; dataString = [dataString stringByReplacingOccurrencesOfString:@\"\ \" withString:@\"\"]; NSData *utf8Data = [dataString dataUsingEncoding:NSUTF8StringEncoding];NSArray *arr = [NSJSONSerialization JSONObjectWithData:utf8Data options:NS

二、CF里他们总说0什么意啊？
ns应该是NICESHOT的简写，就是漂亮，打得好的意思