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我正在使用 NSURLSession 委托方式发出 http get 请求以从服务器获取 json 数据。我最终将在我的 NSURLSessionDataDelegate 中收到的 NSData 传递给模型对象以更新数组，如下所示：

func URLSession(session: NSURLSession, dataTask: NSURLSessionDataTask, didReceiveData data: NSData) {
    networkDelegate?.updateGameList(data)
    dataTask.resume()
}

一旦数据进入 updateGameList 函数，如果我尝试使用 NSJSONSerialization.JSONObjectWithData，就会发生奇怪的事情。如果我不尝试使用 NSJSONSerialization，而只是将 NSData 转换为字符串，那么它看起来就像我期望的正确响应，如下所示：

Optional([{"id":"a19610e4-675e-40b3-8335-085b61bfb0e3","name":"tttt","status":"PLAYING"},
{"id":"3be2e411-0086-46fd-8fc9-38d11831d0fb","name":"LWP TEST","status":"PLAYING"},
{"id":"b5d97d73-1ce2-4e5b-8b38-805835e2a21d","name":"asd","status":"PLAYING"},
{"id":"8a15575c-4c2c-4b46-ad5b-51b4b2680416","name":"MsGame","status":"WAITING"},
{"id":"b54531b8-5323-4630-929c-6eb2cfebde63","name":"423","status":"PLAYING"},
{"id":"5a7cfaa0-e2a4-41f6-bda2-a854a2d00a57","name":"4234","status":"PLAYING"}])

但是，一旦我尝试将 NSData 与 NSJSONSerialization.JSONObjectWithData 一起使用来创建 NSArray，它就会开始抛出错误，因为数据似乎在开始或结束时被截断，如下所示：

Optional([{"id":"a19610e4-675e-40b3-8335-085b61bfb0e3","name":"tttt","status":"PLAYING"},{"id":"3be2e411-0086-46fd-8fc9-38d11831d0fb","name":"LWP TEST","status":"PLAYING"},      
{"id":"6d4e9731-61be-4191-bb9a-a30b6395a4a2","name":"RANDOMBOT","status":"PLAYING"},{"id":"c31b363c-f565-4f4a-a6f1-1ac219425f40","name":"Testament ","status":"PLAYING"},
{"id":"af14d8bc-37a0-4ec3-88de-ee364344d720","name":"Testament ","status":"PLAYING"},
{"id":"29439dd9-357d-445b-856c-39862e19c2fc","name":"Testament ","status":"PLAYING"},{"id":"cc29046f-4e80-422d-a103-5be175e799c9","name":"matt7","status":"PLAYING"},
{"id":"ff75c546-0e9b-4560-8efb-d0fa5be61cde","name":"u","status":"DONE"},{"id":"3d88df55-6f84-469c-a18e-27e463dc30eb","name":"test","status":"PLAYING"},{"id":"40eb1b13-21c3-4c8d-a379-e6b85329374b","name":"test","status":"PLAYING"}, 
{"id":"4e7519dd-79d3-4229-8d0e-47ca112dc08f","name":"test","status":"PLAYING"},{"id":"32ce49cc-17aa-47ca-8b9f-1c35dbdb78e6","name":"test","status":"PLAYING"},
{"id":"f5d5c961-17eb-421d-86b1-fbbadfb795da","name":"test","status":"PLAYING")

update game list error Error Domain=NSCocoaErrorDomain Code=3840 
"Unexpected end of file while parsing object." 
UserInfo={NSDebugDescription=Unexpected end of file while parsing object.}

这是 updateGameList 函数，当我注释掉带有 JSONSerialization 代码的 do-catch 块时，dataString 会打印出正确的响应，当我取消注释它时，它会运行多次，几乎就像它正在尝试处理数据一样一次块而不是一次全部。如果我取出 .AllowFragments 选项，它会告诉我将其放入，当我放入时，它会导致 json 数据未正确开始或结束的真正错误。

func updateGameList(gameListData:NSData) {
    let dataString = NSString(data: gameListData, encoding: NSUTF8StringEncoding)
    print(dataString)

    do {
        let gameList:NSArray = try NSJSONSerialization.JSONObjectWithData(gameListData, options: [.AllowFragments]) as! NSArray
    }
    catch {
        print("update game list error \(error)")
    }

}
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1 回答 1

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从文档中引用：

此委托方法可能会被多次调用，并且每次调用仅提供自上次调用以来接收到的数据。如果需要，应用程序负责积累这些数据。

因此，您观察到的是一个特征：数据以块的形式接收（很可能是因为原始服务器使用Transfer-Encoding: chunked），因此您不能期望能够单独解析每个块 - 您必须将所有块累积到 from一个响应，然后您可以尝试对其进行解析。

于 2018-01-06T09:55:46.673 回答