protobuf的安装及使用

yifei_

发布于 2022-11-14 14:31:23

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发布于 2022-11-14 14:31:23

文章被收录于专栏：yifei的专栏

Linux下protobuf的安装过程&简单使用。 protobuf是google开发的一个灵活的、高效的用于序列化数据的协议。相比较XML和JSON格式，protobuf更小、更快、更便捷。

安装

下载链接：https://github.com/protocolbuffers/protobuf/releases ，我是用c++，所以下载protobuf-cpp就行了。

tar -xzvf protobuf-*.tar.gz

cd protobuf-*

./configure –prefix=/usr/local/protobuf

make (可能会等好一段时间)

make check

make install

vim /etc/profile

export PATH=$PATH:/usr/local/protobuf/bin/
export PKG_CONFIG_PATH=/usr/local/protobuf/lib/pkgconfig/

source /etc/profile

protoc –version #测试是否安装成功

使用方法

cd ~/test

vim address.proto

package tutorial;

message Persion {
    required string name = 1;
    required int32 age = 2;
}

message AddressBook {
    repeated Persion persion = 1;
}

protoc -I=. –cpp_out=. address.proto #在当前文件夹生成cpp的.h和.cc文件

vim write.cpp

#include <iostream>
#include <fstream>
#include <string>
#include "address.pb.h"

using namespace std;

void PromptForAddress(tutorial::Persion *persion) {
    cout << "Enter persion name:" << endl;
    string name;
    cin >> name;
    persion->set_name(name);

    int age;
    cin >> age;
    persion->set_age(age);
}

int main(int argc, char **argv) {
    //GOOGLE_PROTOBUF_VERIFY_VERSION;

    if (argc != 2) {
        cerr << "Usage: " << argv[0] << " ADDRESS_BOOL_FILE" << endl;
        return -1;
    }

    tutorial::AddressBook address_book;

    {
        fstream input(argv[1], ios::in | ios::binary);
        if (!input) {
            cout << argv[1] << ": File not found. Creating a new file." << endl;
        }
        else if (!address_book.ParseFromIstream(&input)) {
            cerr << "Filed to parse address book." << endl;
            return -1;
        }
    }

    // Add an address
    PromptForAddress(address_book.add_persion());

    {
        fstream output(argv[1], ios::out | ios::trunc | ios::binary);
        if (!address_book.SerializeToOstream(&output)) {
            cerr << "Failed to write address book." << endl;
            return -1;
        }
    }

    // Optional: Delete all global objects allocated by libprotobuf.
    //google::protobuf::ShutdownProtobufLibrary();

    return 0;
}

read.cpp

#include <iostream>
#include <fstream>
#include <string>
#include "address.pb.h"

using namespace std;

void ListPeople(const tutorial::AddressBook& address_book) {
    for (int i = 0; i < address_book.persion_size(); i++) {
        const tutorial::Persion& persion = address_book.persion(i);

        cout << persion.name() << " " << persion.age() << endl;
    }
}

int main(int argc, char **argv) {
    //GOOGLE_PROTOBUF_VERIFY_VERSION;

    if (argc != 2) {
        cerr << "Usage: " << argv[0] << " ADDRESS_BOOL_FILE" << endl;
        return -1;
    }

    tutorial::AddressBook address_book;

    {
        fstream input(argv[1], ios::in | ios::binary);
        if (!address_book.ParseFromIstream(&input)) {
            cerr << "Filed to parse address book." << endl;
            return -1;
        }
        input.close();
    }

    ListPeople(address_book);

    // Optional: Delete all global objects allocated by libprotobuf.
    //google::protobuf::ShutdownProtobufLibrary();

    return 0;
}

编译两个文件

g++ address.pb.cc write.cpp -o write `pkg-config --cflags --libs protobuf`
g++ address.pb.cc read.cpp -o read `pkg-config --cflags --libs protobuf`

运行

./write data.txt
aaa 999
./read data.txt
aaa 999

问题

运行write时，提示找不到动态链接库

添加安装路径下的lib路径
export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/usr/local/protobuf/lib

编码示例

package test
message hello {
   int32 id = 1;//id=300
   string str = 2;//str="hello"
}

key 1 >> 1000|0 >> 1000	>> 08
yield 300 >> ‭0010   010 1100‬ >> 010 1100   000 0010 >> 1010 1100   0000 0010 >> ac 02

key 2 >> 10000|10 >> 0001 0010 >> 12
yield hello 长度05
	>> 68 65 6c 6c 6f
	>> 01101000  01100101 01101100 01101100 01101111
	>> 
result: 08 ac 02 12 05 68 65 6c 6c 6f