设计模式＝＝装饰模式—ecorator）

/* * 装饰模式—ecorator） * *   *  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++");    }}