protobuf的基本使用示例

protobuf的基本使用示例

1、编写msgtype文件

test.proto

syntax = "proto3";
package msgType;

enum EnumTest
{
	TEST0 = 0x00;
	TEST1 = 0x01;
	TEST2 = 0x02;
	TEST3 = 0x03;
}

message ProtoTestSub
{
	int32 test1 = 1;
	string test2 = 2;
}

message ProtoTest
{
	int32 int32_test = 1;
	string str_test = 2;
	repeated double dou_test = 3;
	repeated ProtoTestSub sub_test = 4;
	EnumTest eunm_test = 5;
	bytes bytes_test = 6;
}

2、生成对应的头文件以及源文件

root@root:/root/protobuf# protoc --cpp_out=./ ./test.proto.proto
root@root:/root/protobuf# ls
a.out  include  mybuild  protobuf_main.cpp  test.pb.cc  test.pb.h  test.proto

生成对应的*.pb.cc *.pb.h 文件 只需将这两个文件加到自己的工程目录中去

3、示例程序

protobuf_main.cpp

#include <iostream>
#include <vector>
#include <algorithm>
#include "test.pb.h"

void MyPrint(unsigned char temp)
{
     printf("%02x ",(temp)&0xFF);
}

int main(void )
{
	//1、序列化  protobuf的基本使用
	msgType:: ProtoTest cls_proto_test1;
    cls_proto_test1.set_int32_test(123);
    cls_proto_test1.set_str_test("FlyInCoding");
    //多个 repeated使用
    cls_proto_test1.add_dou_test(56.023);
    cls_proto_test1.add_dou_test(78.023);
    //嵌套类的使用
    msgType:: ProtoTestSub * pcls_temp = cls_proto_test1.add_sub_test();
    pcls_temp->set_test1(12);
    pcls_temp->set_test2("zxcvbnm");
    pcls_temp = cls_proto_test1.add_sub_test();
    pcls_temp->set_test1(34);
    pcls_temp->set_test2("asdfghjkl");
    cls_proto_test1.set_eunm_test(msgType::TEST0);
    //protobuf调试打印函数 打印成字符串
    cls_proto_test1.PrintDebugString();
    //序列化之后的大小
    int ilen = cls_proto_test1.ByteSize();
    //序列化成数组
    std::vector <unsigned char> vec_test1;
    vec_test1.resize(ilen);
    cls_proto_test1.SerializePartialToArray(vec_test1.data(),ilen);
    printf("cls_proto_test1 len is %d\n",ilen);
    //容器类遍历的通用办法
    printf("**************************************************\n");
    std::for_each(vec_test1.begin(),vec_test1.end(),MyPrint);
    printf("**************************************************\n");
    //序列化成字符串
    std::string str_temp;
    cls_proto_test1.SerializeToString(&str_temp);
    printf("**************************************************\n");
    std::for_each(str_temp.begin(),str_temp.end(),MyPrint);
    printf("**************************************************\n");
    /*********************************************************
        protobuf有个问题 如果里面数据都为整型 且都为0时 序列化之后的数据大小也为0
        整型为0的数据 不计入整个序列化的数据长度
        doubule float 空的字符串则没有此规律
    **********************************************************/
    msgType:: ProtoTest cls_proto_test2;
    cls_proto_test2.set_int32_test(0);
    //cls_proto_test2.set_str_test("");
    //cls_proto_test2.add_dou_test(0);
    //cls_proto_test2.add_dou_test(0);
    //msgType:: ProtoTestSub * pcls_temp2 = cls_proto_test2.add_sub_test();
    //pcls_temp2->set_test1(0);
    //pcls_temp2->set_test2("");
    //pcls_temp2 = cls_proto_test2.add_sub_test();
   // pcls_temp2->set_test1(0);
    //pcls_temp2->set_test2("");
    //cls_proto_test2.set_eunm_test(msgType::TEST0);
    //protobuf调试打印函数 打印成字符串
    cls_proto_test2.PrintDebugString();
    int ilen2 = cls_proto_test2.ByteSize();
    printf("cls_proto_test1 ilen2 is %d\n",ilen2);
    // 反序列化 从数组进行反序列化 
    msgType::ProtoTest cls_proto_test3;
    cls_proto_test3.ParseFromArray(vec_test1.data(),vec_test1.size());
    cls_proto_test3.PrintDebugString();
    printf("int32_test %d \n",cls_proto_test3.int32_test());
    printf("eunm_test %d \n",cls_proto_test3.eunm_test());
    printf("double count  %d \n",cls_proto_test3.dou_test_size());
    printf("double0   %f \n",cls_proto_test3.dou_test(0));
    printf("double1   %f \n",cls_proto_test3.dou_test(1));
    msgType:: ProtoTestSub cls_temp ;
    for(int i = 0;i < cls_proto_test3.sub_test_size();i++)
    {
        cls_temp = cls_proto_test3.sub_test(i);
        cls_temp.PrintDebugString();
    }


	return 0;
}

4、编译及运行

root@root:/root/protobuf# g++ protobuf_main.cpp test.pb.cc -lprotobuf
root@root:/root/protobuf# ./a.out 
int32_test: 123
str_test: "FlyInCoding"
dou_test: 56.023
dou_test: 78.023
sub_test {
  test1: 12
  test2: "zxcvbnm"
}
sub_test {
  test1: 34
  test2: "asdfghjkl"
}
cls_proto_test1 len is 61
**************************************************
08 7b 12 0b 77 61 6e 78 75 65 78 69 61 6e 67 1a 10 6d e7 fb a9 f1 02 4c 40 b6 f3 fd d4 78 81 53 40 22 0b 08 0c 12 07 7a 78 63 76 62 6e 6d 22 0d 08 22 12 09 61 73 64 66 67 68 6a 6b 6c **************************************************
**************************************************
08 7b 12 0b 77 61 6e 78 75 65 78 69 61 6e 67 1a 10 6d e7 fb a9 f1 02 4c 40 b6 f3 fd d4 78 81 53 40 22 0b 08 0c 12 07 7a 78 63 76 62 6e 6d 22 0d 08 22 12 09 61 73 64 66 67 68 6a 6b 6c **************************************************
cls_proto_test1 ilen2 is 0
int32_test: 123
str_test: "FlyInCoding"
dou_test: 56.023
dou_test: 78.023
sub_test {
  test1: 12
  test2: "zxcvbnm"
}
sub_test {
  test1: 34
  test2: "asdfghjkl"
}
int32_test 123 
eunm_test 0 
double count  2 
double0   56.023000 
double1   78.023000 
test1: 12
test2: "zxcvbnm"
test1: 34
test2: "asdfghjkl"
root@root:/root/protobuf#