1、策略模式

理解：就是通过传不同的参数，调用不同的对象

代码实操

public interface IStrategy {
    void operate();
}

public class BackDoor implements IStrategy {
    public void operate() {
        System.out.println("找乔国老帮忙，让吴国太给孙权施加压力");
    }
}

public class GivenGreenLight implements IStrategy {
    public void operate() {
        System.out.println("求吴国太开个绿灯,放行！");
    }
}

public class Context {
    private IStrategy iStrategy;

    public Context(IStrategy iStrategy) {
        this.iStrategy = iStrategy;
    }
    public void operate(){
        this.iStrategy.operate();
    }
}


public class Zhaoyun {
    public static void main(String[] args) {
        Context context=new Context(new BackDoor());
        context.operate();
    }
}

2、代理模式

理解：就是代理类的构造方法设置成接口类型

代码演示：

public interface KindWomen {
    //这种类型的女人能做什么事情呢？
    public void makeEyesWithMan(); //抛媚眼


    public void happyWithMan(); //happy what? You know that!
}


public class PanJinLian implements KindWomen {
    public void happyWithMan() {
        System.out.println("潘金莲在和男人做那个.....");
    }

    public void makeEyesWithMan() {
        System.out.println("潘金莲抛媚眼");
    }
}


public class ProxyClass {
    private KindWomen kindWomen;

    public ProxyClass(KindWomen kindWomen) {
        this.kindWomen = kindWomen;
    }
    public ProxyClass() {
        this.kindWomen = new PanJinLian();
    }
    public void happyWithMan() {
        this.kindWomen.happyWithMan(); //自己老了，干不了，可以让年轻的代替
    }
    public void makeEyesWithMan() {
        this.kindWomen.makeEyesWithMan(); //王婆这么大年龄了，谁看她抛媚眼？！
    }
}


public class Ximenqing {
    public static void main(String[] args) {
        ProxyClass proxyClass=new ProxyClass();
        proxyClass.happyWithMan();

    }
}

3、单例模式

理解：私有化构造方法、提供一个对外的方法来创建对象

代码实现：

public class SingletonPattern {
    private static final SingletonPattern single=new SingletonPattern();

    public SingletonPattern() {
    }
    public synchronized static SingletonPattern getInstance(){
        return single;
    }
}