1.策略模式Strategy pattern

今天药忘吃喽~ 2023-01-17 10:55 75阅读 0赞

**1.场景：**  
三个妙计，一个锦囊，一个赵云，妙计是小亮同志给的，妙计是放置在锦囊里

**2.类图**  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70]  
**3.程序**

public interface IStrategy { 
    
        void operate();
    }
    
    public class BackDoor implements IStrategy{ 
        @Override
        public void operate() { 
            System.out.println("backdoor");
        }
    }
    
    public class BlockEnemy implements IStrategy { 
        @Override
        public void operate() { 
            System.out.println("BlockEnemy");
        }
    }
    
    public class GivenGreenLight implements IStrategy { 
        @Override
        public void operate() { 
            System.out.println("GivenGreenLight");
        }
    }
    
    public class Context { 
    
    
        //构造函数，使用哪个
        private IStrategy strategy;
    
    
        public Context(IStrategy strategy) { 
            this.strategy = strategy;
        }
        public void operate(){ 
            this.strategy.operate();
        }
    }
    
    
    public class Zhaoyun { 
    
        public static void main(String[] args) { 
    
            Context context;
    
            System.out.println("1");
            context = new Context(new BackDoor());
            context.operate();
            System.out.println();
    
            System.out.println("2");
            context = new Context(new GivenGreenLight());
            context.operate();
            System.out.println();
    
            System.out.println("3");
            context = new Context(new BlockEnemy());
            context.operate();
            System.out.println();
        }
    }

**4.策略模式的好处就是**：  
体现了高内聚低耦合的特性，扩展性，即 OCP 原则，策略类可以继续增加下去，只要修改 Context.java 就可以了

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3dlaXhpbl8zOTc5NTA0OQ_size_16_color_FFFFFF_t_70]: /images/20221021/191750097e234b3da3ae457661d817ca.png