我正在使用一个客户端 – 服务器应用程序,它使用boost :: serialization库来满足它的序列化需求.
我需要对似乎不起作用的多态对象进行序列化和反序列化.文档确实表示它是受支持的,但没有相关示例显示我在这里做的工作.所以,我不太确定.我的问题是可以使用boost来序列化/反序列化多态对象吗？如果是,我在这里做错什么？
谢谢！
码：
using namespace std;
class base {
public:
int data1;
friend class boost::serialization::access;
void serialize(boost::archive::polymorphic_iarchive & ar,const unsigned int file_version) {
ar & data1;
}
void serialize(boost::archive::polymorphic_oarchive & ar,const unsigned int file_version){
ar & data1;
}
public:
base() {};
base(int _d) : data1(_d) {}
virtual void foo() const {std::cout << "base" << std::endl;}
};
class derived : public base {
public:
int data2;
friend class boost::serialization::access;
void serialize(boost::archive::polymorphic_iarchive & ar,const unsigned int file_version) {
ar & boost::serialization::base_object<base>(*this) & data2;
}
void serialize(boost::archive::polymorphic_oarchive & ar,const unsigned int file_version){
ar & boost::serialization::base_object<base>(*this) & data2;
}
public:
derived() {};
derived(int _b,int _d) : base(_b),data2(_d) {}
virtual void foo() const {std::cout << "derived" << std::endl;}
};
int main(int argc,char *argv[]) {
// client
const base *b1 = new derived(1,2);
std::ostringstream oss;
boost::archive::polymorphic_text_oarchive oa(oss);
oa << *b1;
// server
base *b2 = new derived(3,4);
std::istringstream iss(oss.str());
boost::archive::polymorphic_text_iarchive ia(iss);
ia >> *b2;
// prints 1,ok
cout << b2->data1 << endl;
// prints 4,why wasn't the derived class data written?
cout << (dynamic_cast<derived*>(b2))->data2 << endl;
return 0;
}
解决方法
找到一个决议.我不得不使用语句导出派生类：
BOOST_CLASS_EXPORT(derived);
发布一些适用于某些更正的内容.
using namespace std;
class base {
public:
int data1;
friend class boost::serialization::access;
template<typename Archive>
void serialize(Archive & ar,const unsigned int file_version) {
ar & data1;
}
public:
base() {};
base(int _d) : data1(_d) {}
virtual void foo() const {std::cout << "base" << std::endl;}
};
class derived : public base {
public:
int data2;
friend class boost::serialization::access;
template<typename Archive>
void serialize(Archive & ar,const unsigned int file_version) {
ar & boost::serialization::base_object<base>(*this);
ar & data2;
}
public:
derived() {};
derived(int _b,data2(_d) {}
virtual void foo() const {std::cout << "derived" << std::endl;}
};
BOOST_CLASS_EXPORT(derived);
int main(int argc,char *argv[]) {
// client
// Assign to base type
std::unique_ptr<const base> b1(new derived(1,2));
std::ostringstream oss;
boost::archive::text_oarchive oa(oss);
oa & b1.get();
// server
// Retrieve derived type from base
std::unique_ptr<base> b2;
std::istringstream iss(oss.str());
boost::archive::text_iarchive ia(iss);
{
base *temp;
ia & temp;
b2.reset(temp);
}
cout << b2->data1 << endl;
cout << (dynamic_cast<derived*>(b2.get()))->data2 << endl;
return 0;
}