字典转son

NSError *error;
NSData *jsonData = [NSJSONSerialization dataWithJSONObject:data options:NSJSONWritingPrettyPrinted error:&error];//此处data参数是我上面提到的key为"data"的数组
NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];