我想在这个帖子里面总结两个问题:一个是通过ReST获取Json的语句,这个比较简单
另一个是如何将Json包一层一层转存为字典,并最终通过keyword: String获得所需内容的方法
废话不说,来看代码
首先是服务器返回的Json形式,这里以youtube API为例,因为google做的Json包很规范(都是 String: String 或者 String: Int)
youtube API 的 请求 URL 形式(我这里仅获取关键字搜索视频列表)是
https://www.googleapis.com/youtube/v3/search?part=snippet&q=视频关键字&type=video&key=你的API Key
其中,视频关键字比如 minecraft
API Key 形如 AIzaSyDDqTGpVR7jxeozoOEjH6SLaRdw0YY-HPQ
其返回的Json包形式为
{ "kind": "youtube#searchListResponse", "etag": ""uQc-MPTsstrHkQcRXL3IWLmeNsM/dJyYeiv8CbvQiayof_7MqRQOSi8"", "nextPageToken": "CAUQAA", "regionCode": "AU", "pageInfo": { "totalResults": 1000000, "resultsPerPage": 5 }, "items": [ { "kind": "youtube#searchResult", "etag": ""uQc-MPTsstrHkQcRXL3IWLmeNsM/ey6kUbVRRdmcLIPpklkbtxDp_-o"", "id": { "kind": "youtube#video", "videoId": "XgdgO5UzdR4" }, "snippet": { "publishedAt": "2016-11-27T12:00:01.000Z", "channelId": "UCUVa51UA_690sEKyRbHb-5A", "title": "5 Werewolves Caught on Camera & Spotted In Real Life!", "description": "5 Werewolves Caught on Tape & Spotted In Real Life! Description: Myths and stories of humans with the ability to transform into animals exist across all human ...", "thumbnails": { "default": { "url": "https://i.ytimg.com/vi/XgdgO5UzdR4/default.jpg", "width": 120, "height": 90 }, "medium": { "url": "https://i.ytimg.com/vi/XgdgO5UzdR4/mqdefault.jpg", "width": 320, "height": 180 }, "high": { "url": "https://i.ytimg.com/vi/XgdgO5UzdR4/hqdefault.jpg", "width": 480, "height": 360 } }, "channelTitle": "Top 5s Finest", "liveBroadcastContent": "none" } }, { "kind": "youtube#searchResult", "etag": ""uQc-MPTsstrHkQcRXL3IWLmeNsM/LKJrjJEelN2h1v58M533Dwv_fjs"", "id": { "kind": "youtube#video", "videoId": "KUS0454UUDM" }, "snippet": { "publishedAt": "2016-08-03T10:16:33.000Z", "channelId": "UC0rzsIrAxF4kCsALP6J2EsA", "title": "MAIN-MAIN: WEREWOLF", "description": "Yang mau liat tutorial cara mainnya, klik di sini: https://youtu.be/ShGULqRjLMk.", "thumbnails": { "default": { "url": "https://i.ytimg.com/vi/KUS0454UUDM/default.jpg", "width": 120, "height": 90 }, "medium": { "url": "https://i.ytimg.com/vi/KUS0454UUDM/mqdefault.jpg", "width": 320, "height": 180 }, "high": { "url": "https://i.ytimg.com/vi/KUS0454UUDM/hqdefault.jpg", "width": 480, "height": 360 } }, "channelTitle": "Raditya Dika", "liveBroadcastContent": "none" } }, { "kind": "youtube#searchResult", "etag": ""uQc-MPTsstrHkQcRXL3IWLmeNsM/8qIl76CAeB__wn-Sd_g4pik1XT0"", "id": { "kind": "youtube#video", "videoId": "fScsIQ8wgNo" }, "snippet": { "publishedAt": "2016-10-02T22:21:35.000Z", "channelId": "UCNUohh38MTkgY4xKpFeVGmQ", "title": "Werewolf Scenes - My Favorite Transformation HD", "description": "Werewolf Scenes - My Favorite Transformation HD.", "thumbnails": { "default": { "url": "https://i.ytimg.com/vi/fScsIQ8wgNo/default.jpg", "width": 120, "height": 90 }, "medium": { "url": "https://i.ytimg.com/vi/fScsIQ8wgNo/mqdefault.jpg", "width": 320, "height": 180 }, "high": { "url": "https://i.ytimg.com/vi/fScsIQ8wgNo/hqdefault.jpg", "width": 480, "height": 360 } }, "channelTitle": "ENJOY PLEASE", "liveBroadcastContent": "none" } }, { "kind": "youtube#searchResult", "etag": ""uQc-MPTsstrHkQcRXL3IWLmeNsM/SByO_v4iInfFZ5GUe2xJUYXIWh4"", "id": { "kind": "youtube#video", "videoId": "ShGULqRjLMk" }, "snippet": { "publishedAt": "2016-08-03T10:13:33.000Z", "channelId": "UC0rzsIrAxF4kCsALP6J2EsA", "title": "TUTORIAL: MAIN WEREWOLF", "description": "Ini adalah video tutorial untuk main werewolf. Untuk melihat video permainannya, bisa klik di sini: https://youtu.be/KUS0454UUDM.", "thumbnails": { "default": { "url": "https://i.ytimg.com/vi/ShGULqRjLMk/default.jpg", "width": 120, "height": 90 }, "medium": { "url": "https://i.ytimg.com/vi/ShGULqRjLMk/mqdefault.jpg", "width": 320, "height": 180 }, "high": { "url": "https://i.ytimg.com/vi/ShGULqRjLMk/hqdefault.jpg", "width": 480, "height": 360 } }, "channelTitle": "Raditya Dika", "liveBroadcastContent": "none" } }, { "kind": "youtube#searchResult", "etag": ""uQc-MPTsstrHkQcRXL3IWLmeNsM/NjscIZ4D3C-FDPsnBKe-j5tslrE"", "id": { "kind": "youtube#video", "videoId": "MI1Yi2AUVAc" }, "snippet": { "publishedAt": "2016-09-09T07:27:23.000Z", "channelId": "UCNUohh38MTkgY4xKpFeVGmQ", "title": "Vampire vs Werewolf Fight Scene HD - Van Helsing - Vampire vs Lycan Wolf", "description": "Vampire vs Werewolf Fight Scene HD - Van Helsing - Vampire vs Lycan Wolf.", "thumbnails": { "default": { "url": "https://i.ytimg.com/vi/MI1Yi2AUVAc/default.jpg", "width": 120, "height": 90 }, "medium": { "url": "https://i.ytimg.com/vi/MI1Yi2AUVAc/mqdefault.jpg", "width": 320, "height": 180 }, "high": { "url": "https://i.ytimg.com/vi/MI1Yi2AUVAc/hqdefault.jpg", "width": 480, "height": 360 } }, "channelTitle": "ENJOY PLEASE", "liveBroadcastContent": "none" } } ] }
---------------------------------------------------------------------------------------------------------------------
第 0 层
{ }
第一层
{
"kind":"youtube#searchListResponse",
"etag":""uQc-MPTsstrHkQcRXL3IWLmeNsM/g4lxZZLl2WXJPiISOtol-Vf33d8"",
"nextPageToken":"CAUQAA",
"regionCode":"US",
"pageInfo":{ },
"items":[ ]
}
第二层
对于 pageInfo
{
"totalResults":1000000,
"resultsPerPage":5
}
对于 items (注意那个中括号)
[ [
{
"kind":"youtube#searchResult",
"etag":""uQc-MPTsstrHkQcRXL3IWLmeNsM/ey6kUbVRRdmcLIPpklkbtxDp_-o"",
"id":{ },
"snippet":{ }
},
{
"kind":"youtube#searchResult",
"etag":""uQc-MPTsstrHkQcRXL3IWLmeNsM/LKJrjJEelN2h1v58M533Dwv_fjs"",
"id":{ },
"snippet":{ }
},
{
"kind":"youtube#searchResult",
"etag":""uQc-MPTsstrHkQcRXL3IWLmeNsM/8qIl76CAeB__wn-Sd_g4pik1XT0"",
"id":{ },
"snippet":{ }
},
{
"kind":"youtube#searchResult",
"etag":""uQc-MPTsstrHkQcRXL3IWLmeNsM/SByO_v4iInfFZ5GUe2xJUYXIWh4"",
"id":{ },
"snippet":{ }
},
{
"kind":"youtube#searchResult",
"etag":""uQc-MPTsstrHkQcRXL3IWLmeNsM/NjscIZ4D3C-FDPsnBKe-j5tslrE"",
"id":{ },
"snippet":{ }
}
]
这就是说,中括号里面的内容实际上是一个数组,这个数组有五个元素。
第三层
以其中一个元素为例
对于 id
{
"kind":"youtube#video",
"videoId":"XgdgO5UzdR4"
}
对于 snippet
{
"publishedAt":"2016-11-27T12:00:01.000Z",
"channelId":"UCUVa51UA_690sEKyRbHb-5A",
"title":"5 Werewolves Caught on Camera & Spotted In Real Life!",
"description":"5 Werewolves Caught on Tape & Spotted In Real Life! Description: Myths and stories of humans with the ability to transform into animals exist across all human ...",
"thumbnails":{ },
"channelTitle":"Top 5s Finest",
"liveBroadcastContent":"none"
}
第四层
对于 thumbnails
{
"default":{ },
"medium":{ },
"high":{ }
}
第五层
对于 default
{
"url":"https://i.ytimg.com/vi/XgdgO5UzdR4/default.jpg",
"width":120,
"height":90
}
其它两个类似
至此Json 包解析完毕。
然后附上代码。首先是ReST请求部分
然后是Json解析部分
只解释Json解析部分。
我现在的目的是取出四个key值:视频的title、description、thumbnail default url 还有 videoId
过程是这样:
根据我上面的分析,从第一层开始(第 0 层不算)每层都建立[String: AnyObject]字典或数组(根据Json那一层的结构而定)。在最后一层只有String内容的时候,也可以建立[String: String]字典(也就是idDict也可以建成[String: String]的,别的不可以。)
第一层 - resultDict 这个不能建成[String: String],因为pageInfo和items关键字对应的不是String,而是一个或多个子字典。
第二层 - 因为pageInfo里面的内容我不需要(如需要建字典),所以只有items对应的数组 -- itemsArray (建数组因为items本身是五个元素组成的数组,在前面已经说明。)
第三层 - 对于 id -- idDict字典,这个可以建[String: AnyObject]也可以建[String: String](因为内容只有String,建AnyObject的话,就需要cast一下(as! String)。)
对于 snippet -- snippetDict字典,这个必须[String: AnyObject]
第四层 - thumbnailDict
第五层 - defaultDict,其它两个Key里面的信息不需要,如果需要,也可以建相应字典提取出来。
然后我建了一个每个元素都是[String: AnyObject]字典的Array,形如[[String: AnyObject]],用来储存我提取出来的四个keyword对应的信息。当然,这个数组建成[[String: String]]也是可以的。当时对这个代码理解还不深,属于半迷糊状态。
然后就大功告成。
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