在message_lite.h中定义了SerializeToString ，SerializeToArray ，SerializeToCodedStream ，SerializeToZeroCopyStream 其它序列化到IO流、序列化到文件等接口在它的子类message.h文件中提供。
另外，在util/json_util.h文件中定义了protobuf与json相互转换的接口(需要注意的是:当json字符串字段的值等于protobuf中字段的默认值,message->json则此字段不会出现在json中)。
#include#include #include #include #include #include #include #include #include #include #include "game.pb.h"void serializeToString(pt::rsp_login& rsp){ //序列化到字符串和从字符串解析数据 std::string str{}; rsp.SerializeToString(&str); std::cout << "serialize to string:" << str << std::endl; pt::rsp_login rsp2{}; rsp2.ParseFromString(str); std::cout << "parse from string size:" << rsp2.ByteSize() << std::endl; auto temp_str = rsp.SerializeAsString(); std::cout << "serialize as string:" << temp_str << std::endl;}void serializeToArray(pt::rsp_login& rsp){ //序列化到数组和从数组解析数据 std::vector buff; buff.resize(rsp.ByteSize()); rsp.SerializeToArray(buff.data(), buff.size()); pt::rsp_login rsp2{}; if (!rsp2.ParseFromArray(buff.data(), (int)buff.size())) { std::cout << "parse error\n"; } std::cout << "parse from array size:" << rsp2.ByteSize() << std::endl;}void serializeToCodeStream(pt::rsp_login& rsp){ using namespace google::protobuf::io; int fd1 = open("myfile", O_CREAT | O_RDWR); if (fd1 == -1) { return; } ZeroCopyOutputStream *raw_output = new FileOutputStream(fd1); google::protobuf::io::CodedOutputStream coded_output(raw_output); rsp.SerializeToCodedStream(&coded_output); delete raw_output; close(fd1); pt::rsp_login rsp2{}; int fd2 = open("myfile", O_RDONLY); if (fd2 == -1) { return; } ZeroCopyInputStream *raw_input = new FileInputStream(fd2); google::protobuf::io::CodedInputStream coded_input(raw_input); rsp2.ParseFromCodedStream(&coded_input); delete raw_input; close(fd2);}void serializeToStream(pt::rsp_login& rsp){ std::fstream fs1("stream.info", std::ios::out | std::ios::binary); rsp.SerializeToOstream(&fs1); fs1.close(); pt::rsp_login rsp2{}; std::fstream fs2("stream.info", std::ios::in | std::ios::binary); rsp2.ParseFromIstream(&fs2); fs2.close(); std::cout << "parse in stream:" << rsp2.ByteSize() << std::endl;}void serializeToFile(pt::rsp_login& rsp){ //序列化到文件 std::ofstream ofile; auto fd = open("game.info", O_CREAT | O_TRUNC | O_RDWR, 0644); if (fd <= 0) { std::cout << "open file error" << std::endl; return; } rsp.SerializeToFileDescriptor(fd); close(fd); pt::rsp_login rsp2{}; fd = open("game.info", O_RDONLY); if (fd <= 0) { std::cout << "serialize to file error" << std::endl; return; } rsp2.ParseFromFileDescriptor(fd); close(fd); std::cout << "parse from file rsp2.size:" << rsp2.ByteSize() << std::endl;}void jsonMessageConvent(pt::rsp_login& rsp){ //如果字段值=protobuf中的类型默认值,则此字段不会转换到Json字符串中 std::string json{}; google::protobuf::util::MessageToJsonString(rsp, &json); std::cout << "message to json:" << json << std::endl; //json字符串中字段的值=protobuf中字段类型默认值,则此json字段不会转换到protobuf消息中 pt::rsp_login rsp2{}; google::protobuf::util::JsonStringToMessage(json, &rsp2); std::cout << "json to message size:" << rsp2.ByteSize() << std::endl;}int main(){ pt::rsp_login rsp{}; rsp.set_ret(pt::rsp_login_RET_SUCCESS); auto user_info = rsp.mutable_user_info(); user_info->set_nickname("dsw"); user_info->set_icon("345DS55GF34D774S"); user_info->set_coin(2000); user_info->set_location("zh"); for (int i = 0; i < 5; i++) { auto record = rsp.add_record(); record->set_time("2017/4/13 12:22:11"); record->set_kill(i * 4); record->set_dead(i * 2); record->set_assist(i * 5); } serializeToString(rsp); serializeToArray(rsp); serializeToCodeStream(rsp); serializeToStream(rsp); serializeToFile(rsp); jsonMessageConvent(rsp); return 0;}