【设计模式_2】AdapterPattern适配器

Myth丶恋晨 2022-10-05 13:00 151阅读 0赞

## 一、适配器模式简介 ##

“换个包装再度利用”，适配器的功能就是介入既有内容和需要的结果之间，作为沟通的桥梁。

Adapter Pattern又称Wrapper Pattern，Wrapper 意为“包装纸”，好像一件平平无奇的商品，经过包装纸一番装扮后，摇身一变成为送人的礼品。某物具有转换能力就意味着它做适配器、包装器。

## 二、样例1——继承 ##

程序利用类的适配器模式，输出（Hello）以及\*Hello\*  
**实体类Banner**

package AdapterExtends;
    
    public class Banner { 
        private String title;
        public Banner(String title){ 
            this.title = title;
        }
        public void showWithParen(){ 
            System.out.println("("+title+")");
        }
        public void showWithAster(){ 
            System.out.println("*"+title+"*");
        }
    }

**Print接口**

package AdapterExtends;
    
    public interface Print { 
        public abstract void printWeak();
        public abstract void printStrong();
    
    }

**PrintBanner实现类**

package AdapterExtends;
    
    public class PrintBanner extends Banner implements Print { 
        public PrintBanner(String title) { 
            super(title);
        }
    
        @Override
        public void printWeak() { 
            showWithParen();
        }
    
        @Override
        public void printStrong() { 
            showWithAster();
        }
    }

**测试类**

package AdapterExtends;
    
    public class TestAdapterExtends { 
        public static void main(String[] args) { 
            Print ad = new PrintBanner("Hello");
            ad.printStrong();
            ad.printWeak();
        }
    }

**结果**  
![在这里插入图片描述][20210609170155291.png]  
![参考书籍《设计模式在Java中的应用》][Java]

## 三、样例2——委托 ##

这回小改一番，将**Print接口改为抽象类**

package AdapterDelegation;
    
    public abstract class Print { 
        public abstract void printWeak();
        public abstract void printStrong();
    }

**PrintBanner实现类**

package AdapterDelegation;
    
    import AdapterExtends.Banner;
    
    /*Banner委托PrintBanner执行原来的方法*/
    public class PrintBanner extends Print{ 
        private Banner banner;
        public PrintBanner(String title){ 
            this.banner = new Banner(title);
        }
    
        @Override
        public void printWeak() { 
            banner.showWithParen();
        }
    
        @Override
        public void printStrong() { 
            banner.showWithAster();
        }
    }

**测试类**

package AdapterDelegation;
    /*通过PrintBanner的构造方法产生Banner对象，将数据存在banner字段内*/
    public class TestAdapterDelegation { 
        public static void main(String[] args) { 
            /*声明抽象类Print对象，实例化PrintBanner对象*/
            Print ad = new PrintBanner("HelloDelegation");
            ad.printStrong();
            ad.printWeak();
        }
    }

**结果**  
![在这里插入图片描述][20210609170123693.png]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FkaWRhczc0ODkxNDk2_size_16_color_FFFFFF_t_70]

[20210609170155291.png]: /images/20221005/3589bb78fbff4c29981bfccd52ff384d.png
[Java]: /images/20221005/dab54c9a765b48059a432b9f1eccd8d6.png
[20210609170123693.png]: /images/20221005/97cbbbb31fb64c999a47d4260c43a069.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2FkaWRhczc0ODkxNDk2_size_16_color_FFFFFF_t_70]: /images/20221005/b759f385f28c458c8eff0b87691c9991.png