ProtoBuffer 简单例子

最近学了一下protobuf，写了一个简单的例子，如下：

person.proto文件

message Person{
    required string name = 1;
    required int32 age = 2;
    optional string email = 3;
    enum PhoneType{
        MOBILE = 1;
        HOME = 2;
        WORK = 3;
    }
    message Phone{
        required int32 id = 1;
        optional PhoneType type = 2 [default = HOME];
    }
    repeated string phoneNum = 4;  //对应于cpp的vector
}

安装好protoc以后，执行protoc person.proto --cpp_out=. 生成 person.pb.h和person.pb.cpp

写文件(write_person.cpp)：

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

using namespace std;

int main(){
    string buffer;
    Person person;
    person.set_name("chemical");
    person.set_age(29);
    person.set_email("ygliang2009@gmail.com");
    person.add_phonenum("abc");
    person.add_phonenum("def");
    fstream output("myfile",ios::out|ios::binary);
    person.SerializeToString(&buffer); //用这个方法，通常不用SerializeToOstream
    output.write(buffer.c_str(),buffer.size());
    return 0;
}

编译时要把生成的cpp和源文件一起编译，如下：g++ write_person.cpp person.pb.cpp -o write_person -I your_proto_include_path -L your_proto_lib_path -lprotoc -lprotobuf运行时记得要加上LD_LIBRARY_PATH=your_proto_lib_path

读文件(read_person.cpp)：

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

using namespace std;

int main(){
    Person *person = new Person;
    char buffer[BUFSIZ];
    fstream input("myfile",ios::in|ios::binary);
    input.read(buffer,sizeof(Person));
    person->ParseFromString(buffer);  //用这个方法，通常不用ParseFromString
    cout << person->name() << person->phonenum(0) << endl;
    return 0;
}

编译运行方法同上：g++ read_person.cpp person.pb.cpp -o read_person -I your_proto_include_path -L your_proto_lib_path -lprotoc -lprotobuf

 

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