１．Java设计模式－－＞装饰者模式

　作为一个Java小白，面向对象编程的几个特性：封装＼继承＼多态，我一直真正了解的不多．这个模式却让我一下理解了多态的好处：它可以很方便的对系统进行解耦．废话不讲，上代码和注释
　
１．公共接口

public interface Appearance{    void draw();}

2.基本实现类和一个用作装饰别的Appearance子类的抽象类

//这里列出来两个基本实现类public class Circle implements Appearance{    @override    public void draw(){      System.out.println("画个圆形");    }}public class Rectangle implements Appearance{    @override    public void draw(){      System.out.println("画个矩形");}

//一个装饰Appearance子类的抽象类public abstract class AppearanceDecorator implements Appearance{    //声明为proteced可以被子类继承    protected Appearance decoratedAppearance;    public AppearanceDecorator(Appearance decoratedAppearance){      this.decoratedAppearance = decoratedrAppearance;    }    @override    public void draw(){      decoratedAppearance.draw();    }}

3.装饰的具体实现类

public class RedAppearanceDecorator extends AppearanceDecorator{    public RedAppearanceDecorator(Appearance decoratedAppearance){      super(decoratedAppearance);    }    private void setRedBorder(){      System.out.println("进行镶边");      System.out.println("done!红色镶边");    }    @override    public void draw(){      decoratedAppearance.draw();      setRedBorder();    }}

接下来：用测试类来测试一下即可：

public class Test{    public static void(String[] args){      Appearance circle = new Circle();      circle.draw();      Appearance rectangle = new Rectangle();      rectangle.draw();      Appearance redCircle = new RedAppearanceDecorator( new Circle() );      redCircle.draw();    }}

最后，简单一提，学习设计模式一方面是要加深对java体系的理解，另一方面也是增长自己的设计能力．
在Java的io操作中，
BufferedWirter \ OutputStreamWriter 是Writer的子类
其中BufferedWriter就是具体的装饰类．以后，会结合具体的Java或者Andoid源代码进行讲解．
源代码我现在阅读起来还有些费力气，但是最起码要有读源代码的意识，这是开发者必备的技能．