public class Memento {

    //攻击力
    private int vit;
    //防御力
    private int def;
    public Memento(int vit, int def) {
        super();
        this.vit = vit;
        this.def = def;
    }
    public int getVit() {
        return vit;
    }
    public void setVit(int vit) {
        this.vit = vit;
    }
    public int getDef() {
        return def;
    }
    public void setDef(int def) {
        this.def = def;
    }
    
}

import java.util.ArrayList;
import java.util.HashMap;

//守护者对象, 保存游戏角色的状态
public class Caretaker {

    //如果只保存一次状态
    private Memento memento;
    //对GameRole 保存多次状态
    //private ArrayList<Memento> mementos;
    //对多个游戏角色保存多个状态
    //private HashMap<String, ArrayList<Memento>> rolesMementos;

    public Memento getMemento() {
        return memento;
    }

    public void setMemento(Memento memento) {
        this.memento = memento;
    }

}

public class GameRole {

    private int vit;
    private int def;

    //创建Memento ,即根据当前的状态得到Memento
    public Memento createMemento() {
        return new Memento(vit, def);
    }

    //从备忘录对象，恢复GameRole的状态
    public void recoverGameRoleFromMemento(Memento memento) {
        this.vit = memento.getVit();
        this.def = memento.getDef();
    }

    //显示当前游戏角色的状态
    public void display() {
        System.out.println("游戏角色当前的攻击力：" + this.vit + " 防御力: " + this.def);
    }

    public int getVit() {
        return vit;
    }

    public void setVit(int vit) {
        this.vit = vit;
    }

    public int getDef() {
        return def;
    }

    public void setDef(int def) {
        this.def = def;
    }

}

public class Client {

    public static void main(String[] args) {
        //创建游戏角色
        GameRole gameRole = new GameRole();
        gameRole.setVit(100);
        gameRole.setDef(100);

        System.out.println("和boss大战前的状态");
        gameRole.display();

        //把当前状态保存caretaker
        Caretaker caretaker = new Caretaker();
        caretaker.setMemento(gameRole.createMemento());

        System.out.println("和boss大战~~~");
        gameRole.setDef(30);
        gameRole.setVit(30);

        gameRole.display();

        System.out.println("大战后，使用备忘录对象恢复到站前");

        gameRole.recoverGameRoleFromMemento(caretaker.getMemento());
        System.out.println("恢复后的状态");
        gameRole.display();
    }

}