Java面向对象编程（封装/继承/多态）实例解析

本文主要介绍了面向对象的三大特征实例解析，下面看看具体内容。

封装

封装一个Teacher和Student类

package com.hz.test;
public class Teacher {
 private String name;
 private String majorDirection;
 private String teachCourse;
 private int teachAge;
 public Teacher() {
   super();
 }
 public Teacher(String name,String majorDirection,String teachCourse,int teachAge) {
   this.name = name;
   this.majorDirection = majorDirection;
   this.teachCourse = teachCourse;
   this.teachAge = teachAge;
 }
 public String getName() {
   return name;
 }
 public void setName(String name) {
   this.name = name;
 }
 public String getMajorDirection() {
   return majorDirection;
 }
 public void setMajorDirection(String majorDirection) {
   this.majorDirection = majorDirection;
 }
 public String getTeachCourse() {
   return teachCourse;
 }
 public void setTeachCourse(String teachCourse) {
   this.teachCourse = teachCourse;
 }
 public int getTeachAge() {
   return teachAge;
 }
 public void setTeachAge(int teachAge) {
   this.teachAge = teachAge;
 }

public String toString() {
   return "姓名=" + getName() + ", 专业方向=" + getMajorDirection()
       + ", 所教课程=" + getTeachCourse() + ", 教龄=" + getTeachAge();
 }
}

Student类

package com.hz.test;
import java.util.Arrays;
/**
* @author ztw
*
*/
public class Student {
 private String name;
 private int age;
 private String[] courses;
 private String interest;
 public Student() {
   super();
 }
 public Student(String name,int age,String[] courses,String interest) {
   this.name = name;
   this.age = age;
   this.courses = courses;
   this.interest = interest;
 }
 public void setName(String name){
   this.name = name;
 }
 public String getName(){
   return name;
 }
 public void setAge(int age){
   if(age<0){
     System.out.println("年龄不能为负值");
   }else{
     this.age = age;
   }
 }
 public int getAge(){
   return age;
 }
 public void setCourses(String[] courses){
   this.courses = courses;
 }
 public String getCourses(){
   return Arrays.toString(courses);
 }
 public void setInterest(String interest){
   this.interest = interest;
 }
 public String getInterest(){
   return interest;
 }
 public String toString() {
   return "姓名=" + getName() + ", 年龄=" + getAge() + ", 课程=" + getCourses()
       + ", 兴趣=" + getInterest();
 }  
}

测试类

package com.hz.test;
public class Test {
 public static void main(String[] args) {
   String arr[] = {"阿斯达","是的","大概","太诱惑"};
   Student stu = new Student("张三",21,arr,"打球");
   Teacher tea = new Teacher("王五","阿斯达","阿斯达",99);
   System.out.println(stu);
   System.out.println(tea);
 }
}

输出结果：

姓名=张三, 年龄=21, 课程=[阿斯达, 是的, 大概, 太诱惑], 兴趣=打球
姓名=王五, 专业方向=阿斯达, 所教课程=阿斯达, 教龄=99

继承

定义Play，TaoistPriest，Master，Warrior

public class Play {
 String main;
 public Play(String main) {
   this.main = main;
 }
 public void hitMonster() {
   System.out.println(main+"打怪");
 }
}

/**
* TaoistPriest:道士
* @author ztw
*
*/
public class TaoistPriest extends Play {
 {
   System.out.print("我是道士：");
 }
 public TaoistPriest(String main) {
   super(main);
 }
}

/**
* Master:法师
* @author ztw
*
*/
public class Master extends Play{
 {
   System.out.print("我是法师：");
 }
 public Master(String main) {
   super(main);
 }
}

/**
* Warrior:武士
* @author ztw
*
*/
public class Warrior extends Play{
 {
   System.out.print("我是武士：");
 }
 public Warrior(String main) {
   super(main);
 }
}

测试类

public class Test {
 public static void main(String[] args) {
   TaoistPriest tp = new TaoistPriest("灵魂火符");
   tp.hitMonster();
   Master m = new Master("雷电术");
   m.hitMonster();
   Warrior w = new Warrior("烈火术");
   w.hitMonster();
 }
}

输出结果：

我是道士：灵魂火符打怪
我是法师：雷电术打怪
我是武士：烈火术打怪

多态

服务器，客户端交互

LoginListener

public interface LoginListener {
 public void succeed(String msg);
 public void failed(String msg);
}

MyLoginListener

public class MyLoginListener implements LoginListener{
 public void succeed(String msg) {
   System.out.println(msg);
 }
 public void failed(String msg) {
   System.out.println(msg);
 }
}

Server

public class Server {
 public void login(String userName,String password,LoginListener listener) {
   System.out.print("loading");
   for (int i = 0; i < 10; i++) {
     try {
       Thread.sleep(100*i);
       System.out.print(".");
     } catch (InterruptedException e) {
       // TODO Auto-generated catch block
       e.printStackTrace();
     }
   }
   if(userName.equals("zhangsan") && password.equals("123")){
     if(listener!=null){
       listener.succeed("登录成功");
     }
   }else{
     if(listener!=null){
       listener.succeed("登录失败");
     }
   }
 }
}

测试类

public class LoginTest {
 public static void main(String[] args) {
   Scanner sc = new Scanner(System.in);
   System.out.println("请输入用户名：");
   String userName = sc.next();
   System.out.println("请输入用户密码：");
   String password = sc.next();
   Server server = new Server();
   server.login(userName, password, new MyLoginListener());
 }
}

输出结果

请输入用户名：
zhangsan
请输入用户密码：
123
loading……….登录成功

来源：http://blog.csdn.net/qq_33624284/article/details/53606306