在Java编程语言中，嵌套了非常多设计模式的思想，比如IO流中的缓冲流就使用到以下要介绍的装饰者设计模式。

演示样例代码：

 * 抽象构件角色：定义一个抽象接口，来规范准备附加功能的类

 * @author Admin

 *

 */

public interface Drink {             //被装饰者的基类

	public String description();

	public int price();

}

/**

 * 详细构件角色：将要被附加功能的类，实现抽象构件角色接口

 * @author Admin

 *

 */

public class SoyaBeanMilk implements Drink{       //被装饰者的详细类

	public String description() {

		return "豆浆";

	}

	public int price() {

		return 2;

	}

}

/**

 * 抽象装饰者角色:持有对详细构件角色的引用(被装饰者)并实现抽象构件角色一致的接口

 * @author Admin

 *

 */

public class Decorator implements Drink{           //装饰者的基类

	private Drink drink;

	public Decorator(Drink drink) {

		this.drink = drink;

	}

	public String description() {

		return drink.description();

	}

	public int price() {

		return drink.price();

	}

}

/**

 * 详细装饰角色：实现抽象装饰者角色。负责为详细构件加入额外功能.

 * @author Admin

 *

 */

public class Sugar extends Decorator{       //装饰者详细类

	public Sugar(Drink drink) {

		super(drink);

	}

	public String description() {

		return super.description()+" 糖";

	}

	public int price() {

		return super.price()+1;

	}

}

/**

 * 详细装饰角色：实现抽象装饰者角色，负责为详细构件加入额外功能.

 * @author Admin

 *

 */

public class BlackBean extends Decorator{

	public BlackBean(Drink drink) {

		super(drink);

	}

	public String description() {

		return super.description()+" 黑豆";

	}

	public int price() {

		return super.price()+3;

	}

}

/**

 * 測试类（測试装饰者模式）

 * @author Admin

 *

 */

public class Test {

	public static void main(String[] args) {

		Drink drink = new SoyaBeanMilk();       //被装饰者(豆浆)

		System.out.println(drink.description()+"花费："+drink.price());

		Drink drink1 = new Sugar(drink);        //糖是装饰者类。用来装饰豆浆

		System.out.println(drink1.description()+"花费："+drink1.price());

		Drink drink2 = new BlackBean(drink);    //用黑豆来装饰豆浆

		System.out.println(drink2.description()+"花费："+drink2.price());

		Drink drink3 = new BlackBean(drink1);   //用黑豆来装饰糖豆浆

		System.out.println(drink3.description()+"花费："+drink3.price());

	}

}

实验结果：