将10 MB JSON响应转换为NSDictionary的最有效方法是什么？ [英] What's the most efficient way of converting a 10 MB JSON response into an NSDictionary?

问题描述

我们的应用必须以最小的远程http请求显示大量数据，因此我们在后端添加了一个端点，它将所有必要的数据作为单个json响应提供。这导致~1.5MB（压缩）或大约8 MB的未压缩json格式文本。

Our app must display a big chunk of data with minimal remote http requests, so we have added an endpoint to our backend that provides all the necessary data as a single json response. This results in ~1.5MB (compressed) or roughly 8 MBs of uncompressed json-formatted text.

没有太大的问题，它下载10 - 30秒我们'使用ASIHTTPRequest将整个响应写入磁盘。

Not much of a problem, it downloads in 10 - 30 seconds and we're using ASIHTTPRequest to write the whole response to disk.

现在有趣的部分 - 在将未压缩文件读入内存映射字符串后，我们使用stig的 json-framework 将其转换为NSDictionary。这对我们的应用程序的其余部分以及其他API端点的典型2 KB json响应非常有效。但是，将这8 MB的数据反序列化需要几秒钟（模拟器）到几分钟（3G和第二代iPod Touch）。

Now comes the fun part - after reading the uncompressed file into a memory mapped string, we use stig's json-framework to convert it into an NSDictionary. This has worked very well for the rest of our app and the typical 2 KB json response for the rest of our API endpoints. However, deserializing these 8 MBs of data takes from a couple of seconds (simulator) to minutes (3G and 2nd gen iPod Touch).

我正在研究读取所有这些数据的最佳方法。

我很想使用直接来自后端的二进制plist，但我们正在使用Java和我的避风港找不到符合我们要求的合适的图书馆，并且在如此紧迫的截止日期前，写下我们自己可能不是最好的想法。

I would love to use binary plists served straight from the backend, but we are using Java and I haven't found a proper library that fits our requirements, and with such a tight deadline, writing our own might not be the best idea.

如果它有任何帮助，我们正在解析的json字符串主要是一个X项的数组，如下所示：

If it helps in any way, the json string we are parsing is mostly an array of X items, like so:

{
    "items": [ { "key1": "value1", "key2": "value2" },
               { "key1": "value1", "key2": "value2" },
               { "key1": "value1", "key2": "value2" },
               { "key1": "value1", "key2": "value2" },
               { "key1": "value1", "key2": "value2" },
               { "key1": "value1", "key2": "value2" }
             ]
}

将此8 MB json格式化字符串读入的最有效方法是什么？内存中的NSDictionary？

推荐答案

看看 JSONKit 。它非常快，如果你的JSON有很多重复的键和值（这是常见的），它的最近实例化的对象缓存将大大减少用于最终<$ c $的内存量c> NSDictionary 。

Take a look at JSONKit. It's very fast, and if your JSON has a lot of keys and values that repeat themselves (as is common), its "recently instantiated object cache" will dramatically cut down on the amount of memory used for the "final" NSDictionary.

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