一、整體程式碼

      01.cpp

#include <iostream>
using namespace std;
class DBHelper
{
public:
    DBHelper()
    {
        cout<<"DB ..."<<endl;
    }
    ~DBHelper()
    {
        cout<<"~DB ..."<<endl;
    }
    void Open()
    {
        cout<<"Open ..."<<endl;
    }
    void Close()
    {
        cout<<"Close ..."<<endl;
    }
    void Query()
    {
        cout<<"Query ..."<<endl;
    }
};
class DB
{
public:
    DB()
    {
        db_ = new DBHelper;
    }
    ~DB()
    {
        delete db_;
    }
    DBHelper* operator->()
    {
        return db_;
    }
private:
    DBHelper* db_;
};
int main(void)
{
    DB db;
    db->Open();//db operaot->().Open()
    db->Query();
    db->Close();
    return 0;
}