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
 #include "person.pb.h"
 #include
 #include

 using namespace std;

 int main(){
     string buffer;
     Person person;
     person.set_name("chemical");
     person.set_age(29);
     person.set_email("[email protected]");
     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
 #include "person.pb.h"
 #include
 #include

 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