设计模式＝＝装饰模式（Decorator）
/* * 装饰模式（Decorator） * * * 以对客户透明的方式来扩展对象的功能。 * 用户根据功能需求随意选取组成对象的成分，通过方法的链式调用来实现。 * 可以给对象动态的增加功能，比继承灵活性更大。 */package model;public class TestDecorator { public static void main(String[] args) { Teacher t1 = new SimpleTeacher(); Teacher t2 = new CppTeacher(t1); Teacher t3 = new JavaTeacher(t2); t3.teach(); // t.teach(); }}abstract class Teacher { public abstract void teach();}class SimpleTeacher extends Teacher { public void teach() { System.out.println("Good Good Study, Day Day Up"); }}class JavaTeacher extends Teacher { Teacher teacher; public JavaTeacher(Teacher t) { this.teacher = t; } public void teach() { teacher.teach(); System.out.println("Teach Java"); }}class CppTeacher extends Teacher { Teacher teacher; public CppTeacher(Teacher t) { this.teacher = t; } public void teach() { teacher.teach(); System.out.println("Teach C++"); }}?