iphone - iOS 的复杂 JSON 响应

Question

我正在使用 twitter api 的一部分，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;
        };
    }
)

这里我关心的是，在真正将整个内容设置为数据模型之前，有没有具体的方法可以将参数设置为空字符串？

就像有两个实体一样 "time_zone"= "";和“utc_offset”=“”；无论如何要遍历 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，它可能会导致我的应用程序在某些时候出现一些循环漏洞而崩溃，因此我只想弄清楚如何遍历如此复杂的 json 来检查每个实体并为 NSNull 类型类设置空字符串。我确实尝试过递归方式，但它只给出了上层键的列表，而不是字典中的实体。

谢谢

Answer 1

"<null>"值似乎是字符串，而不是 NSNulls。如果要将字符串替换为"" , 你可以使用 stringByReplacingOccurrencesOfstring:withString:大量转换它们(因为存在转换您不打算转换的内容的风险)。

(但可以肯定的是，如果您提供一些原始 JSON，与 NSArray/NSDictionary 对象的 Objective-C description 相比，这显然是您正在展示的内容，那将会很好。)