c++ 模拟java的反射，根据类名动态创建类

参考：

https://blog.csdn.net/jnu_simba/article/details/9318799

原先有静态变量依赖问题，

https://blog.csdn.net/anonymalias/article/details/38473985

参考这个，又做了改进：

https://blog.csdn.net/liulong1567/article/details/45273017

https://www.mimec.org/blog?page=2

classfactory.h文件

#ifndef CLASSFACTORY_H

#define CLASSFACTORY_H

#include <map>

#include <string>

using namespace std;

#include "boardbase.h"

typedef void* (*register_func)();

class Class

{

public:

    static void* newInstance(const string& class_name) {

        map<string, register_func>::iterator it = constructors().find(class_name);

        if (it == constructors().end())

            return NULL;

        else

            return it->second();

    }

    static void registerClass(const string& class_name, register_func func) {

        constructors()[class_name] = func;

    }

private:

    //避免static初始化顺序问题导致崩溃

    static map<string, register_func>& constructors()

    {

        /* key is class name and value is function to create instance of class */

        static map<string, register_func> m_register;

        return m_register;

    }

};

class ClassFactory

{

public:

    static BoardBase* createBoardBase(const string& bank_name) {

        return (BoardBase*)Class::newInstance(bank_name);

    }

};

class Register

{

public:

    Register(const string& class_name, register_func func) {

        Class::registerClass(class_name, func);

    }

};

//在cpp文件中使用

#define REGISTER_CLASS(class_name) \

    class class_name##Register { \

    public: \

    static void* newInstance() { \

    return new class_name; \

    } \

    private: \

    static Register reg; \

    };\

    Register class_name##Register::reg(#class_name,class_name##Register::newInstance);

#endif // CLASSFACTORY_H