一. 前言

FlatBuffers相对于ProBuffer的性能差异网上资料很多，这里暂时不做讨论。先用一个简单的例子来讨论简单的FlatBuffers的用法。

二. Schema (IDL, Interface Definition Language)

namespace MyGame; enum PhoneType : int { MOBILE = 0, HOME = 1, WORK = 2, } table PhoneNumber { number:string (required); type:int; } table People { name:string; age:int; phone:[PhoneNumber]; } table AddressBook { people:[People]; } root_type AddressBook;

上面是生成代码的描述文件，保存为Sample.fbs.

三. Generate Code

执行命令行： flatc.exe --csharp -o Resource/Sample Sample.fbs 则可以生成目标语言的代码。

–csharp指定了编译的目标语言。-o则用于指定输出文件路径，如果没有提供则将当前目录作为输出目录。最后是fbs文件名。

详细说明见官方文档。

四. 工程文件准备

新建一个win32的工程文件，引入对应语言的库文件（可以编译成dll文件放入工程，也可以直接拷贝git里面的源代码）。引入刚刚生成的文件。准备完毕。

五. Generate Binary 然后直接读取二进制

这一步的目标是生成需要的二进制文件，并读取生成的二进制然后显示是否正确。

Encode的代码如下：

static byte[] EncodeTest(string[] names) { FlatBufferBuilder fbBuilder = new FlatBufferBuilder(1); Offset<People>[] personOffsets = new Offset<People>[names.Length]; for (int i = 0; i < names.Length; i++) { var phoneOffsets = new Offset<PhoneNumber>[3]; for (int j = 0; j < 3; j++) { string formatPhoneNumber = string.Format("{0:D11}", 10000000000 + j + i * 3); var phoneNumber = fbBuilder.CreateString(formatPhoneNumber); var phoneOffset = PhoneNumber.CreatePhoneNumber(fbBuilder, phoneNumber, j); phoneOffsets[j] = phoneOffset; } var pOffset = People.CreatePhoneVector(fbBuilder, phoneOffsets); var name = fbBuilder.CreateString(names[i]); var peopleOffset = People.CreatePeople(fbBuilder, name, 100 + i, pOffset); personOffsets[i] = peopleOffset; } var offset = AddressBook.CreatePeopleVector(fbBuilder, personOffsets); AddressBook.StartAddressBook(fbBuilder); AddressBook.AddPeople(fbBuilder, offset); var eab = AddressBook.EndAddressBook(fbBuilder); AddressBook.FinishAddressBookBuffer(fbBuilder, eab); return fbBuilder.SizedByteArray(); }

Decode的代码如下：

static AddressBook DecodeTest(byte[] datas) { ByteBuffer byteBuffer = new ByteBuffer(datas); return AddressBook.GetRootAsAddressBook(byteBuffer); }

构造假数据并打印的代码如下：

static void Main(string[] args) { while (true) { ConsoleKey inputKey = Console.ReadKey().Key; if (inputKey == ConsoleKey.A) { Console.WriteLine("\n"); string[] names = new string[100]; for (int i = 0; i < 100; i++) { string formatName = string.Format("PeopleName{0:D9}", i + 1); Console.WriteLine(formatName); names[i] = formatName; } byte[] encodeBytes = EncodeTest(names); File.WriteAllBytes(@"AddressBook.ab", encodeBytes); } if (inputKey == ConsoleKey.B) { Console.WriteLine("\nFlatBuffers info:"); var bytes = File.ReadAllBytes(@"AddressBook.ab"); AddressBook addressBook = DecodeTest(bytes); int size = addressBook.PeopleLength; for (int j = 0; j < size; j++) { People? people = addressBook.People(j); if (people != null) { Console.WriteLine("Name:{0},Age:{1}", people.Value.Name, people.Value.Age); int pSize = people.Value.PhoneLength; for (int k = 0; k < pSize; k++) { PhoneNumber? phoneNumber = people.Value.Phone(k); if (phoneNumber != null) { Console.WriteLine("Phone Type,Number:{0},{1}", phoneNumber.Value.Type, phoneNumber.Value.Number); } } } } } } }

运行上面的代码即可构造生成一个二进制文件并打印出里面的内容。

六. 通过二进制文件生成Json文件，方便查看

利用命令行 flatc.exe --raw-binary -t Sample.fbs -- AddressBook.ab 可以生成一个名字叫AddressBook.json的文件，方面查看生成的二进制文件内容是否正确。

注意：AddressBook.ab前面有一个空格。

完毕！