使用protobuf(）

Protobuf的简介请看这里：http://blog.youkuaiyun.com/program_think/archive/2009/05/31/4229773.aspx

哪我们来讲一下该如何使用

1，首先去谷歌网站上下载（https://github.com/google/protobuf） 我下载的是 2.5版本的

2，编译好工程，如图所示(挨个编译，注： test工程不需要编译)，在编译protoc工程的时候， 可能报错，

1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall google::protobuf::compiler::CommandLineInterface::CommandLineInterface(void)" (??0CommandLineInterface@compiler@protobuf@google@@QAE@XZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall google::protobuf::compiler::CommandLineInterface::~CommandLineInterface(void)" (??1CommandLineInterface@compiler@protobuf@google@@QAE@XZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: void __thiscall google::protobuf::compiler::CommandLineInterface::RegisterGenerator(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,class google::protobuf::compiler::CodeGenerator *,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?RegisterGenerator@CommandLineInterface@compiler@protobuf@google@@QAEXABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@PAVCodeGenerator@234@0@Z) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: void __thiscall google::protobuf::compiler::CommandLineInterface::RegisterGenerator(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &,class google::protobuf::compiler::CodeGenerator *,class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?RegisterGenerator@CommandLineInterface@compiler@protobuf@google@@QAEXABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@0PAVCodeGenerator@234@0@Z) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: void __thiscall google::protobuf::compiler::CommandLineInterface::AllowPlugins(class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > const &)" (?AllowPlugins@CommandLineInterface@compiler@protobuf@google@@QAEXABV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@@Z) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: int __thiscall google::protobuf::compiler::CommandLineInterface::Run(int,char const * const * const)" (?Run@CommandLineInterface@compiler@protobuf@google@@QAEHHQBQBD@Z) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall google::protobuf::compiler::cpp::CppGenerator::CppGenerator(void)" (??0CppGenerator@cpp@compiler@protobuf@google@@QAE@XZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall google::protobuf::compiler::cpp::CppGenerator::~CppGenerator(void)" (??1CppGenerator@cpp@compiler@protobuf@google@@UAE@XZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall google::protobuf::compiler::python::Generator::Generator(void)" (??0Generator@python@compiler@protobuf@google@@QAE@XZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall google::protobuf::compiler::python::Generator::~Generator(void)" (??1Generator@python@compiler@protobuf@google@@UAE@XZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: __thiscall google::protobuf::compiler::java::JavaGenerator::JavaGenerator(void)" (??0JavaGenerator@java@compiler@protobuf@google@@QAE@XZ) referenced in function _main
1>main.obj : error LNK2019: unresolved external symbol "public: virtual __thiscall google::protobuf::compiler::java::JavaGenerator::~JavaGenerator(void)" (??1JavaGenerator@java@compiler@protobuf@google@@UAE@XZ) referenced in function _main

解决方案：只需要在protoc的工程main文件中添加如下两下：

#pragma comment(lib, "libprotobuf.lib")  
#pragma comment(lib, "libprotoc.lib")  

再设置lib的路径： 工程熟属性-》链接-》添加静态库库目录即可(也就是debug目录)
即可，

3，编译好之后，在工程libprotobuf中生成debug文件，libprotobuf.lib，protoc.exe三个文件

4，工程libprotobuf中目录下，运行extract_includes.bat，产生include文件夹

5，新建一个工程 testProtoBuf, 将libprotobuf.lib，protoc.exe，include文件夹，这三个文件复制到新建工程的跟目录下，如图所示

5，配置新项目环境，如图所示

6，配置好环境，我们需要在跟目录下创建如下两个文件

7，运行build.bat文件，在上层目录产生两个文件person.pb.h,person.pb.cc,然后将其放到

8，在工程中新建一个cpp文件，如图所示：

代码如下：

#include <iostream>
#include <fstream>
#include <string>
#include "person.pb.h"
#pragma comment (lib,"libprotobuf.lib")

using namespace std;
int main()
{
	Person person;
	person.set_id(6);
	person.set_email("adc");
	person.set_name("gan");

	/*
	文件序列化
	*/
	fstream out("person.xml", ios::out | ios::binary | ios::trunc);
	person.SerializeToOstream(&out);
	out.close();

	//从person.pb文件读取数据
	fstream in("person.xml", ios::in | ios::binary);
	if (!person.ParseFromIstream(&in)) {
		cerr << "Failed to parse person.xml." << endl;
		exit(1);
	}

	cout << "ID: " << person.id() << endl;
	cout << "name: " << person.name() << endl;
	if (person.has_email()) {
		cout << "e-mail: " << person.email() << endl;
	}


	return 0;
}

9，进行编译时，可能会出现一个错误

10.在工程属性中添加如下即可：_SCL_SECURE_NO_WARNINGS