Name: ArduinoJson 7 的新功能 (What's new in ArduinoJson 7)
Uploaded: 2025-05-07T04:05:47.000Z
Duration: 14 min 56 s

情態副詞

The microcontroller landscape has significantly changed in the past five years.

在過去的五年裡，微控制器的格局發生了重大變化。

分詞構句

Previously monopolized by 8-bit microcontrollers, the market is now dominated by 32-bit microcontrollers.

以前，市場由 8 位微控制器壟斷，現在則由 32 位微控制器主導。

This hardware revolution required a redesign of Arduino JSON.

這場硬件革命要求重新設計 Arduino JSON。

Once a competitive advantage of Arduino JSON 6, fixed memory allocation progressively became irrelevant. Arduino JSON 7 redefines the memory management strategy to provide an elegant and straightforward API. In this video, I'll give you an overview of what's new in this release.

固定內存分配曾是 Arduino JSON 6 的競爭優勢，但後來逐漸變得無關緊要。Arduino JSON 7 重新定義了內存管理策略，提供了一個優雅而直接的 API。在本視頻中，我將為您介紹該版本的新功能。

Before we go into the good stuff, I must warn you that Arduino JSON 7 is significantly bigger than version 6. For example, on an Arduino Uno R3, the parser example is 41% bigger and the generator example is 45% bigger. Previously, all my design decisions were aimed at keeping the code small. Indeed, when I designed Arduino JSON 6, most users ran their programs on 8-bit microcontrollers. And that's why I focused so much on code size.

在進入精彩內容之前，我必須提醒您，Arduino JSON 7 比第 6 版大了很多。例如，在 Arduino Uno R3 上，解析器示例要大 41%，生成器示例要大 45%。以前，我所有的設計決定都是為了保持代碼的小巧。事實上，當我設計 Arduino JSON 6 時，大多數用戶都在 8 位微控制器上運行他們的程序。這也是我如此關注代碼大小的原因。

That's how Arduino JSON 6 came to implement a fixed memory allocation strategy. Not only does it reduce the code size, but it also eliminates heap fragmentation and allows stack-based allocations.

Arduino JSON 6 就是這樣實現固定內存分配策略的。它不僅減少了代碼大小，還消除了堆碎片，並允許基於堆棧的分配。

Fixed memory allocation is perfect when resources are scarce but requires more discipline from the programmer. During the past five years, we attended to the rise of 32-bit microcontrollers, first with the ESP8266, then with the ESP32 and all the ARM-based MCUs. 32-bit microcontrollers have much more memory but also a bigger runtime framework, so Arduino JSON now represents a small fraction of the executable. If we compare the parser example on the two versions of the Arduino Uno, we see that Arduino JSON 7 makes up about two-thirds of the executable on R3 but only 7% on R4. Because the proportion is much smaller, the difference between Arduino JSON 6 and 7 is neglectable on 32-bit microcontrollers. For example, on Arduino Uno R4 minima, the parser example only grew by 2.3% and the generator example by 1.7%. As you can see, the size of the library is not so important anymore. Arduino JSON 7 can run on 8-bit microcontrollers but if the memory is tight, it's probably better if you stick with version 6.

在資源稀缺的情況下，固定內存分配非常完美，但對程序員的要求更高。在過去五年中，我們注意到 32 位微控制器的興起，首先是 ESP8266，然後是 ESP32 和所有基於 ARM 的 MCU。32 位微控制器內存更大，但運行時框架也更大，是以 Arduino JSON 現在只佔可執行文件的一小部分。如果我們比較 Arduino Uno 兩個版本上的解析器示例，就會發現 Arduino JSON 7 在 R3 上約佔可執行文件的三分之二，而在 R4 上僅佔 7%。由於比例要小得多，是以在 32 位微控制器上，

Arduino JSON 7 includes stubs for every deprecated feature, so most existing programs should continue to work. The stubs produce informative warning messages that tell you how to upgrade the code.

Arduino JSON 7 包含每個已廢棄功能的存根，是以大多數現有程序都能繼續運行。這些存根會生成翔實的警告資訊，告訴你如何升級代碼。

Of course, since your programs continue to work, you don't have to upgrade right away, but you'll see that the process is very straightforward.

當然，由於您的程序仍在繼續運行，您不必立即升級，但您會發現升級過程非常簡單。

I already published a video explaining the changes in detail, so I'll only give an overview here.

我已經發布了一段視頻，詳細解釋了這些變化，是以在此僅作概述。

The biggest change concerns JSON documents. Arduino JSON 7 exclusively relies on dynamic memory allocation, and you no longer need to specify the capacity upon creation.

最大的變化與 JSON 文檔有關。Arduino JSON 7 完全依賴於動態內存分配，您不再需要在創建時指定容量。

Since we can no longer choose between stack and heap memory, I'll merge static JSON documents and dynamic JSON documents into a single JSON document class.

既然我們無法再在堆棧內存和堆內存之間做出選擇，我將把靜態 JSON 文檔和動態 JSON 文檔合併為一個 JSON 文檔類。

To maintain excellent performance, Arduino JSON 7 reduces heap fragmentation by allocating blocks of 1 kilobyte. String deduplication also reduces the number of allocations, and a short string optimization will soon reduce it even more. The impact on heap fragmentation should be very limited.

為了保持出色的性能，Arduino JSON 7 通過分配 1 千字節的塊來減少堆碎片。重複數據刪除也減少了分配次數，而短字符串優化將很快進一步減少分配次數。對堆碎片的影響應該非常有限。

In fact, the only function that should increase the fragmentation is deserialized JSON because it needs to reallocate blocks for strings. Because the capacity of the JSON document is now elastic, several functions related to memory management became irrelevant. JSON array size, JSON object size, JSON document capacity, and JSON object size are all limited.

事實上，唯一會增加碎片的功能是反序列化 JSON，因為它需要為字符串重新分配塊。由於 JSON 文檔的容量現在是彈性的，是以與內存管理相關的幾個函數變得無關緊要。JSON 數組大小、JSON 對象大小、JSON 文檔容量和 JSON 對象大小都是有限的。

JSON array size, JSON object size, JSON document capacity, JSON document memory usage, and JSON document garbage collect. JSON document shrink to fit, which releases the over-allocated memory, is still available on Arduino JSON 7, but it is automatically called by deserialized JSON, so you probably don't need to call it anymore.

JSON 數組大小、JSON 對象大小、JSON 文檔容量、JSON 文檔內存使用情況以及 JSON 文檔垃圾回收。在 Arduino JSON 7 中，JSON 文檔縮小到合適大小（釋放超量分配的內存）仍然可用，但它會被反序列化的 JSON 自動調用，所以你可能不再需要調用它了。

I changed how we customize the allocator. Instead of passing a template parameter, you must pass a pointer to a polymorphic allocator. This change, inspired by Stude PMR, allows all JSON documents to be compatible with each other, regardless of the allocator.

我改變了自定義分配器的方式。你必須傳遞一個指向多態分配器的指針，而不是傳遞一個模板參數。這一改變受到了 Stude PMR 的啟發，它允許所有 JSON 文檔相互兼容，而無需考慮分配器。

It also allowed me to get rid of the template class BasicJSONDocument.

它還讓我擺脫了模板類 BasicJSONDocument。

I managed to keep all the features of Arduino JSON 6 except one, Shallow Copy. Indeed, due to significant changes in the library, a slot can no longer point to a different document.

我設法保留了 Arduino JSON 6 的所有功能，但淺複製（Shallow Copy）功能除外。事實上，由於庫中的重大變化，槽不能再指向不同的文檔。

If your program calls Shallow Copy, Arduino JSON 7 will do a Deep Copy instead, which could break your program, so watch out.

如果您的程序調用 Shallow Copy（淺複製），Arduino JSON 7 將執行 Deep Copy（深複製），這可能會破壞您的程序，是以請注意。

On a different topic, I took the opportunity to remove one of the library's biggest words.

關於另一個話題，我藉此機會刪除了圖書館最大的一個詞。

CreateNestedArray and CreateNestedObject are a legacy of Arduino JSON 4, and they don't fit with the rest of the API. In Arduino JSON 7, I replaced them with addT and toT. Please see the upgrade guide for details.

創建嵌套數組（CreateNestedArray）和創建嵌套對象（CreateNestedObject）是 Arduino JSON 4 的遺留功能，它們與 API 的其他部分並不兼容。在 Arduino JSON 7 中，我用 addT 和 toT 取代了它們。詳情請參見升級指南。

Now let's see less important changes that should only affect a minority of users and probably don't require your attention.

現在，讓我們來看看不那麼重要的更改，這些更改隻影響少數用戶，可能不需要您的關注。

The first is the removal of the ZeroCopyMode. In version 6, the serialized JSON behaved differently depending on the input type. If the input was a char pointer, it used a ZeroCopyMode.

首先是刪除了 ZeroCopyMode。在第 6 版中，根據輸入類型的不同，序列化 JSON 的行為也不同。如果輸入是字元指針，則使用 ZeroCopyMode。

I was initially a big fan of this feature because it could save a lot of memory.

我最初非常喜歡這項功能，因為它可以節省大量內存。

Unfortunately, the ZeroCopyMode was misunderstood and caused many bugs, so I removed it from Arduino JSON 7.

不幸的是，ZeroCopyMode 被誤解並導致了許多錯誤，是以我從 Arduino JSON 7 中刪除了它。

The second is the removal of the ZeroCopyMode. In version 6, the serialized JSON behaved differently depending on the input type. If the input was a char pointer, it used a ZeroCopyMode.

其次是刪除了 ZeroCopyMode。在第 6 版中，根據輸入類型的不同，序列化 JSON 的行為也不同。如果輸入是字元指針，則使用 ZeroCopyMode。

I removed it from Arduino JSON 7. If your program relied on the ZeroCopyMode, you'll see a significant increase in memory consumption after the upgrade.

如果您的程序依賴於 ZeroCopyMode，升級後內存消耗將大幅增加。

Next, I fixed the weird behavior of serialized JSON with String classes.

接下來，我修正了串行化 JSON 與字符串類之間的奇怪行為。

Indeed, in Arduino JSON 6, serialized JSON treated String objects, such as String or StdString, as streams. So instead of replacing their content, it appended to the end. I fixed it with Arduino JSON 7. Serialized JSON now overwrites the content as one would expect. In theory, this is a breaking change, but I doubt it will break anything in practice. Finally, I changed the string copy policy of the serialized function.

事實上，在 Arduino JSON 6 中，序列化 JSON 將 String 對象（如 String 或 StdString）視為流。是以，它不是替換其內容，而是追加到末尾。我在 Arduino JSON 7 中修復了這一問題，現在序列化 JSON 會按照預期覆蓋內容。從理論上講，這是一個破壞性的改動，但我懷疑它在實踐中會破壞任何東西。最後，我修改了序列化函數的字符串複製策略。

In Arduino JSON 6, raw strings use the same policy as regular strings. All types were stored by copy, except const char pointers, which were stored by pointers.

在 Arduino JSON 6 中，原始字符串使用與普通字符串相同的策略。所有類型都通過複製存儲，但 const char 指針除外，它通過指針存儲。

In Arduino JSON 7, all raw strings are stored by copy.

在 Arduino JSON 7 中，所有原始字符串都是通過複製來存儲的。

I already published a new version of the Arduino JSON Assistant.

我已經發布了 Arduino JSON 助手的新版本。

As you'll see, it's slightly different from what you're used to.

正如你所看到的，它與你所習慣的略有不同。

First of all, the raison d'être of the Assistant changed. Before, the main goal was to help you compute the right capacity for the JSON document. Now, it is to validate that your JSON document can fit in the RAM of your microcontroller.

首先，該助手存在的理由發生了變化。以前，它的主要目標是幫助您計算 JSON 文檔的正確容量。而現在，它的目的是驗證 JSON 文檔是否適合微控制器的 RAM。

Consequently, step 3, which showed how much RAM you should reserve for your JSON document, was removed. The new Assistant still shows the memory consumption, but this was moved to step 2 and doesn't give as many details. In addition to showing the memory consumption, the new Assistant tells you what percentage of the RAM is used.

是以，顯示應為 JSON 文檔預留多少內存的第 3 步被刪除了。新版 "助手 "仍會顯示內存消耗情況，但這一步被移到了第 2 步，而且沒有提供那麼多細節。除了顯示內存消耗外，新版助手還會告訴你內存使用的百分比。

Of course, this requires knowing the amount of memory available on your board, and that's why the first step now asks you to enter the board instead of the processor architecture.

當然，這需要知道電路板上可用的內存量，這就是為什麼第一步要求您輸入電路板而不是處理器架構。

The new Assistant still allows you to design a filter for deserialized JSON, although this feature has changed a little. Instead of choosing deserialize and filter, you must now check enable input filter in the second step.

新版助手仍允許您為反序列化的 JSON 設計過濾器，不過這一功能有了些許變化。現在您必須在第二步中勾選啟用輸入過濾器，而不是選擇反序列化和過濾器。

The last step, which generates a sample program, remains roughly the same, except you can now customize the deserialization program.

最後一步是生成一個示例程序，該步驟大致相同，只是現在可以自定義反序列化程序。

Two settings are available. The first chooses the output for the OR messages, serial or std cout. The second chooses the output for the OR messages, serial or std cout. The second turns flash strings on or off.

有兩種設置可供選擇。第一個設置選擇 OR 資訊的輸出，串行或 std cout。第二個設置選擇 OR 資訊的輸出，串行或 std cout。第二個設置是打開或關閉閃存字符串。

As you probably already saw, all the documentation for Arduino JSON 7 is already there.

正如您可能已經看到的，Arduino JSON 7 的所有文檔都已經在這裡了。

You can select the version on the navigation bar at the top of the screen.

您可以在螢幕頂部的導航欄上選擇版本。

I also updated the troubleshooter to support Arduino JSON 7. You will see that it now starts by asking you which version you use, and I even included Arduino JSON 5 for completeness.

我還更新了故障排除程序以支持 Arduino JSON 7，你會看到它現在會詢問你使用的是哪個版本，為了完整起見，我甚至還包含了 Arduino JSON 5。

If you encounter any issue with the library, please try to self-diagnose your problem with the Arduino JSON troubleshooter. If it is unable to help, please open an issue on GitHub.

如果您在使用該庫時遇到任何問題，請嘗試使用 Arduino JSON 故障排除程序對問題進行自我診斷。如果無法解決問題，請在 GitHub 上提交問題。

Remember to include the troubleshooter report in the issue description. The report gives me the context and tells me what you already tried. It also allows me to continue improving the troubleshooter by adding more choices at the right locations.

記得在問題描述中包含故障排除報告。該報告將為我提供背景資訊，並告訴我您已經嘗試了哪些方法。它還能讓我繼續改進故障排除程序，在正確的位置添加更多選擇。

I published a new edition of my book Mastering Arduino JSON for version 7.

我出版了新版《精通 Arduino JSON》一書的第 7 版。

The overall structure remained the same. Chapter 1 briefly introduces Arduino JSON and what you can do with it. When updating the manuscript, I was amazed by the number of web APIs that had disappeared since the last edition. I included the list so that you realize how important it is to choose your service providers wisely. Chapter 2 teaches elementary

總體結構保持不變。第 1 章簡要介紹了 Arduino JSON 及其用途。在更新手稿時，我對自上一版以來消失的網絡 API 數量之多感到驚訝。我列出了這份清單，以便讓你意識到明智選擇服務提供商是多麼重要。第 2 章教授初級

C++ aspects that most Arduino users ignore. It's called the missing C++ course because it covers what is usually omitted by other courses. Chapters 3 and 4 are the deserialization and serialization tutorials. They are available for free on arduinojson.org. Chapter 5 covers advanced topics such as filtering, deserialization in chunks, JSON streaming, allocators, readers, writers, converters and other valuable techniques. Chapter 6 explains how the library works and how to navigate the code. I rewrote this chapter from scratch and this version is radically different from the previous one. Chapter 7 is a troubleshooting guide. It shows how things can go wrong and how to prevent bugs. Most of this chapter applies to any C++ program, whether it uses arduino json or not. Chapter 8 contains five case studies showing how to use arduino json in different scenarios. I invite you to purchase the book directly at arduinojson.org slash book. Not only will you learn essential things but you'll also support my work allowing me to continue investing a crazy amount of time in improving the library and helping the community.

大多數 Arduino 用戶都會忽略的 C++ 方面。之所以稱其為 "缺失的 C++ 課程"，是因為它涵蓋了其他課程通常忽略的內容。第 3 章和第 4 章是反序列化和序列化教程。這些內容可在 arduinojson.org 上免費獲取。第 5 章涉及高級主題，如過濾、分塊反序列化、JSON 流、分配器、讀取器、寫入器、轉換器和其他有價值的技術。第 6 章介紹了庫的工作原理以及如何瀏覽代碼。我從頭開始重寫了這一章，這個版本與之前的版本截然不同。第 7 章是故障排除指南。它說明了如何出錯以及如何防止出現 bu

As you might imagine, this release has required tremendous work so I might take a break before adding new features. If you've been following me, you know that I rarely announce what's coming in the next version. As usual, I won't make any promise about what's coming up but I can tell you what's on my mind at the moment. First, I want to implement short string optimization which will continue to reduce the number of allocations. Second, I hope I can rewrite the parser in a non-recursive way which will allow me to get rid of deserialization option nesting limit and deserialization error too deep. Next, I want to add a new parser for json 5 which will eliminate the need for arduino json enabled comments. Finally, I'll try to refactor the parsers to support incremental data which will be fantastic for scenarios where you receive the json document piece by piece like with esp async web server. Of course, I'm not making any commitment since my priority might change. All I can promise is that I'll continue working on arduino json as much as my time allows. This wraps up this video on arduino json 7. I hope it answered all the questions you had about this new release. Remember that I published another video explaining how to upgrade your code from arduino json 6 to 7 and I intend to create another one for arduino json 5. As usual,

正如你可能想象的那樣，這個版本需要大量的工作，所以在添加新功能之前，我可能會休息一段時間。如果你一直關注我，就會知道我很少公佈下一個版本的內容。像往常一樣，我不會對即將推出的功能做出任何承諾，但我可以告訴你我目前在想什麼。首先，我想實現短字符串優化，這將繼續減少分配的次數。其次，我希望能以非遞歸方式重寫解析器，這樣就能擺脫反序列化選項嵌套限制和反序列化錯誤過深的問題。接下來，我想為 json 5 添加一個新的解析器，這樣就不需要啟用 arduino json 註釋了。最後，我將嘗試重構解析器，使其支持增量

I turned off the comments to centralize all the supports to the github issues. You'll find the link in the video description. All right, that's all. Thank you for watching!

我關閉了評論，以便將所有支持集中到 github 問題。你可以在視頻描述中找到鏈接。好了，就這樣。感謝您的觀看！