iOS的复杂JSON响应

Question

我正在使用twitter api的某些部分，并使用ASIHTTPREQUEST获取一些JSON响应。下面是JSON表示的样子：

(
    { 
     contributors = "<null>"; 
     coordinates = "<null>"; 
     "created_at" = "Tue Nov 29 15:48:35 +0000 2011"; 
     entities =   { 
      hashtags =    (
      ); 
      media =    (
           { 
        "display_url" = "pic.twitter.com/650E1WRY"; 
        "expanded_url" = "http://twitter.com/ashu1702/status/141544088850796545/photo/1"; 
        id = 141544088854990848; 
        "id_str" = 141544088854990848; 
        indices =      (
         22, 
         42 
        ); 
        "media_url" = "http://p.twimg.com/AfbdmVBCEAAPJvT.jpg"; 
        "media_url_https" = "https://p.twimg.com/AfbdmVBCEAAPJvT.jpg"; 
        sizes =      { 
         large =       { 
          h = 279; 
          resize = fit; 
          w = 215; 
         }; 
         medium =       { 
          h = 279; 
          resize = fit; 
          w = 215; 
         }; 
         small =       { 
          h = 279; 
          resize = fit; 
          w = 215; 
         }; 
         thumb =       { 
          h = 150; 
          resize = crop; 
          w = 150; 
         }; 
        }; 
        type = photo; 
        url = "http://t.co/650E1WRY"; 
       } 
      ); 
      urls =    (
      ); 
      "user_mentions" =    (
      ); 
     }; 
     favorited = 0; 
     geo = "<null>"; 
     id = 141544088850796545; 
     "id_str" = 141544088850796545; 
     "in_reply_to_screen_name" = "<null>"; 
     "in_reply_to_status_id" = "<null>"; 
     "in_reply_to_status_id_str" = "<null>"; 
     "in_reply_to_user_id" = "<null>"; 
     "in_reply_to_user_id_str" = "<null>"; 
     place = "<null>"; 
     "possibly_sensitive" = 0; 
     "retweet_count" = 0; 
     retweeted = 0; 
     source = "<a href=\"http://www.apple.com\" rel=\"nofollow\">iOS</a>"; 
     text = "I am in Syria @(null) http://t.co/650E1WRY"; 
     truncated = 0; 
     user =   { 
      "contributors_enabled" = 0; 
      "created_at" = "Sun May 01 15:20:52 +0000 2011"; 
      "default_profile" = 1; 
      "default_profile_image" = 1; 
      description = "<null>"; 
      "favourites_count" = 0; 
      "follow_request_sent" = "<null>"; 
      "followers_count" = 0; 
      following = "<null>"; 
      "friends_count" = 5; 
      "geo_enabled" = 0; 
      id = 291164338; 
      "id_str" = 291164338; 
      "is_translator" = 0; 
      lang = en; 
      "listed_count" = 0; 
      location = "<null>"; 
      name = "Ashutosh Tiwari"; 
      notifications = "<null>"; 
      "profile_background_color" = C0DEED; 
      "profile_background_image_url" = "http://a0.twimg.com/images/themes/theme1/bg.png"; 
      "profile_background_image_url_https" = "https://si0.twimg.com/images/themes/theme1/bg.png"; 
      "profile_background_tile" = 0; 
      "profile_image_url" = "http://a2.twimg.com/sticky/default_profile_images/default_profile_3_normal.png"; 
      "profile_image_url_https" = "https://si0.twimg.com/sticky/default_profile_images/default_profile_3_normal.png"; 
      "profile_link_color" = 0084B4; 
      "profile_sidebar_border_color" = C0DEED; 
      "profile_sidebar_fill_color" = DDEEF6; 
      "profile_text_color" = 333333; 
      "profile_use_background_image" = 1; 
      protected = 0; 
      "screen_name" = ashu1702; 
      "show_all_inline_media" = 0; 
      "statuses_count" = 62; 
      "time_zone" = "<null>"; 
      url = "<null>"; 
      "utc_offset" = "<null>"; 
      verified = 0; 
     }; 
    } 
) 

我这里是关心，其实之前设定的全部内容以数据模型，有没有设置参数，以空字符串任何具体的方法是什么？

就像有两个实体一样“time_zone”=“”;和“utc_offset”=“”;无论如何要迭代json响应并设置@“”空字符串。我不想在每个关键点都验证NSNULL功能，并且它可能会导致我的应用程序在某个点出现一些循环漏洞，因此我只想弄清楚如何遍历这些复杂的json来检查每个实体并为NSNull类型类设置空字符串。我曾尝试过递归方式，但它只给出了上层关键字列表，而不是字典中的实体。

谢谢

Answer 1

"<null>"值看起来是字符串，而不是NSNull。如果你想用""替换字符串，你可以使用stringByReplacingOccurrencesOfstring:withString:将它们转换成大量的（作为转换你不想要的东西的一些风险）。

（但要肯定的，如果你提出了一些原始的JSON的，在VS的NSArray/NSDictionary的对象这显然是你展示什么样的Objective-C的description这将是一件好事。）

Answer 2

不，你将不得不手动。根据[NSNull null]进行测试是最好的选择。