装饰者模式

代码详解：【设计模式】Java 设计模式之装饰者模式（Decorator）_java 装饰者模式-CSDN博客

// 抽象构件角色
public interface Component {void operation();
}// 具体构件角色
public class ConcreteComponent implements Component {@Overridepublic void operation() {System.out.println("执行具体构件对象的操作");}
}// 装饰角色
public class Decorator implements Component {protected Component component;public Decorator(Component component) {this.component = component;}@Overridepublic void operation() {if (component != null) {component.operation();}}
}// 具体装饰角色A
public class ConcreteDecoratorA extends Decorator {public ConcreteDecoratorA(Component component) {super(component);}@Overridepublic void operation() {super.operation();addedFunctionA();}public void addedFunctionA() {System.out.println("为构件对象添加功能A");}
}// 具体装饰角色B
public class ConcreteDecoratorB extends Decorator {public ConcreteDecoratorB(Component component) {super(component);}@Overridepublic void operation() {super.operation();addedFunctionB();}public void addedFunctionB() {System.out.println("为构件对象添加功能B");}
}

 装者模式的应用：

-mybatis 里的缓存：