|
|
|
|
|
/********* begin *********/
|
|
|
Cat a = new Cat();
|
|
|
a.setName("大花猫");
|
|
|
a.setAge(6);
|
|
|
a.voice();
|
|
|
a.eat();
|
|
|
a.show();
|
|
|
/********* end *********/
|
|
|
|
|
|
// 实例化一个Dog对象，设置属性name和age，调用voice()和eat()方法，再打印出名字和年龄信息
|
|
|
/********* begin *********/
|
|
|
Dog b = new Dog();
|
|
|
b.setName("大黑狗");
|
|
|
b.setAge(8);
|
|
|
b.voice();
|
|
|
b.eat();
|
|
|
b.show();
|
|
|
/********* end *********/
|
|
|
|
|
|
}
|
|
|
}
|
|
|
|
|
|
class Animal {
|
|
|
/********* begin *********/
|
|
|
private String name;
|
|
|
private int age;
|
|
|
|
|
|
public String getName() {
|
|
|
return name;
|
|
|
}
|
|
|
|
|
|
public void setName(String name) {
|
|
|
this.name = name;
|
|
|
}
|
|
|
|
|
|
public int getAge() {
|
|
|
return age;
|
|
|
}
|
|
|
|
|
|
public void setAge(int age) {
|
|
|
this.age = age;
|
|
|
}
|
|
|
|
|
|
public void show() {
|
|
|
System.out.println(name+age+"岁");
|
|
|
}
|
|
|
/********* end *********/
|
|
|
|
|
|
}
|
|
|
|
|
|
class Cat extends Animal {
|
|
|
// 定义Cat类的voice()和eat()方法
|
|
|
/********* begin *********/
|
|
|
|
|
|
public void voice() {
|
|
|
System.out.println(super.getName()+"喵喵叫");
|
|
|
}
|
|
|
|
|
|
public void eat() {
|
|
|
System.out.println(super.getName()+"吃鱼");
|
|
|
}
|
|
|
/********* end *********/
|
|
|
}
|
|
|
|
|
|
class Dog extends Animal {
|
|
|
// 定义Dog类的voice()和eat()方法
|
|
|
/********* begin *********/
|
|
|
public void voice() {
|
|
|
System.out.println(super.getName()+"汪汪叫");
|
|
|
}
|
|
|
|
|
|
public void eat() {
|
|
|
System.out.println(super.getName()+"吃骨头");
|
|
|
}
|
|
|
/********* end *********/
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
package case3;
|
|
|
|
|
|
public class superTest {
|
|
|
public static void main(String[] args) {
|
|
|
// 实例化一个Student类的对象s，为Student对象s中的school赋值，打印输出信息
|
|
|
/********* begin *********/
|
|
|
Student s=new Student("张三",18);
|
|
|
s.school="哈佛大学";
|
|
|
s.print();
|
|
|
/********* end *********/
|
|
|
}
|
|
|
}
|
|
|
class Person {
|
|
|
/********* begin *********/
|
|
|
String name;
|
|
|
int age;
|
|
|
Person(String name,int age){
|
|
|
this.name=name;
|
|
|
this.age=age;
|
|
|
}
|
|
|
/********* end *********/
|
|
|
}
|
|
|
class Student extends Person {
|
|
|
/********* begin *********/
|
|
|
Student(String name,int age){
|
|
|
super(name,age);
|
|
|
}
|
|
|
String school;
|
|
|
void print(){
|
|
|
System.out.println("姓名："+name+"，年龄："+age+"，学校："+school);
|
|
|
}
|
|
|
/********* end *********/
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
package case4;
|
|
|
|
|
|
public class overridingTest {
|
|
|
public static void main(String[] args) {
|
|
|
// 实例化子类对象s，调用talk()方法打印信息
|
|
|
/********* begin *********/
|
|
|
Student s=new Student("张三",18,"哈佛大学");
|
|
|
s.talk();
|
|
|
/********* end *********/
|
|
|
|
|
|
}
|
|
|
}
|
|
|
|
|
|
class Person {
|
|
|
/********* begin *********/
|
|
|
public String name;
|
|
|
public int age;
|
|
|
void talk(){
|
|
|
System.out.println("我是："+name+"，今年："+age+"岁");
|
|
|
}
|
|
|
/********* end *********/
|
|
|
}
|
|
|
|
|
|
class Student extends Person {
|
|
|
/********* begin *********/
|
|
|
String school;
|
|
|
Student(String name,int age,String school){
|
|
|
this.name=name;
|
|
|
this.age=age;
|
|
|
this.school=school;
|
|
|
}
|
|
|
void talk(){
|
|
|
System.out.println("我是："+name+"，今年："+age+"岁，我在"+school+"上学");
|
|
|
}
|
|
|
/********* end *********/
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
package case5;
|
|
|
|
|
|
public class abstractTest {
|
|
|
public static void main(String[] args) {
|
|
|
/********* begin *********/
|
|
|
// 分别实例化Student类与Worker类的对象，并调用各自构造方法初始化类属性。
|
|
|
Student s=new Student("张三",20,"学生");
|
|
|
Worker w=new Worker("李四",30,"工人");
|
|
|
s.talk();
|
|
|
w.talk();
|
|
|
// 分别调用各自类中被复写的talk()方法 打印信息。
|
|
|
/********* end *********/
|
|
|
}
|
|
|
}
|
|
|
|
|
|
// 声明一个名为Person的抽象类，在Person中声明了三个属性name age occupation和一个抽象方法——talk()。
|
|
|
abstract class Person {
|
|
|
/********* begin *********/
|
|
|
String name;
|
|
|
int age;
|
|
|
String occupation;
|
|
|
abstract void talk();
|
|
|
/********* end *********/
|
|
|
}
|
|
|
|
|
|
// Student类继承自Person类，添加带三个参数的构造方法，复写talk()方法 返回姓名、年龄和职业信息
|
|
|
class Student extends Person {
|
|
|
/********* begin *********/
|
|
|
Student(String name,int age,String occupation){
|
|
|
this.name=name;
|
|
|
this.age=age;
|
|
|
this.occupation=occupation;
|
|
|
}
|
|
|
void talk(){
|
|
|
System.out.println("学生——>姓名："+name+"，年龄："+age+"，职业："+occupation+"！");
|
|
|
}
|
|
|
/********* end *********/
|
|
|
}
|
|
|
|
|
|
// Worker类继承自Person类，添加带三个参数的构造方法，复写talk()方法 返回姓名、年龄和职业信息
|
|
|
class Worker extends Person {
|
|
|
/********* begin *********/
|
|
|
Worker(String name,int age,String occupation){
|
|
|
this.name=name;
|
|
|
this.age=age;
|
|
|
this.occupation=occupation;
|
|
|
}
|
|
|
void talk(){
|
|
|
System.out.println("工人——>姓名："+name+"，年龄："+age+"，职业："+occupation+"！");
|
|
|
}
|
|
|
/********* end *********/
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
package case6;
|
|
|
|
|
|
public class finalTest {
|
|
|
public static void main(String args[]) {
|
|
|
Bike1 obj = new Bike1();
|
|
|
obj.run();
|
|
|
|
|
|
Honda honda = new Honda();
|
|
|
honda.run();
|
|
|
|
|
|
Yamaha yamaha = new Yamaha();
|
|
|
yamaha.run();
|
|
|
}
|
|
|
}
|
|
|
//不可以修改 final 变量的值
|
|
|
// final方法,不可以重写
|
|
|
不可以扩展 final 类
|
|
|
class Bike1 {
|
|
|
int speedlimit = 90;
|
|
|
|
|
|
void run() {
|
|
|
speedlimit = 120;
|
|
|
System.out.println("speedlimit=120");
|
|
|
}
|
|
|
}
|
|
|
|
|
|
class Bike2 {
|
|
|
void run() {
|
|
|
System.out.println("running");
|
|
|
}
|
|
|
}
|
|
|
|
|
|
class Honda extends Bike2 {
|
|
|
void run() {
|
|
|
System.out.println("running safely with 100kmph");
|
|
|
}
|
|
|
}
|
|
|
|
|
|
class Bike3 {
|
|
|
}
|
|
|
|
|
|
class Yamaha extends Bike3 {
|
|
|
void run() {
|
|
|
System.out.println("running safely with 100kmph");
|
|
|
}
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
package case7;
|
|
|
|
|
|
public class interfaceTest {
|
|
|
public static void main(String[] args) {
|
|
|
// 实例化一Student的对象s，并调用talk()方法，打印信息
|
|
|
/********* begin *********/
|
|
|
Student s=new Student();
|
|
|
System.out.println(s.talk());
|
|
|
/********* end *********/
|
|
|
}
|
|
|
}
|
|
|
|
|
|
// 声明一个Person接口，并在里面声明三个常量：name、age和occupation，并分别赋值，声明一抽象方法talk()
|
|
|
interface Person {
|
|
|
/********* begin *********/
|
|
|
final String name="张三";
|
|
|
final int age=18;
|
|
|
final String occupation="学生";
|
|
|
public abstract String talk();
|
|
|
/********* end *********/
|
|
|
}
|
|
|
|
|
|
// Student类继承自Person类 复写talk()方法返回姓名、年龄和职业信息
|
|
|
class Student implements Person {
|
|
|
/********* begin *********/
|
|
|
public String talk() {
|
|
|
return "学生——>姓名：" + this.name + "，年龄：" + this.age + "，职业："
|
|
|
+ this.occupation + "！";
|
|
|
}
|
|
|
/********* end *********/
|
|
|
}
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
package case8;
|
|
|
|
|
|
public class TestPolymorphism {
|
|
|
public static void main(String[] args) {
|
|
|
// 以多态方式分别实例化子类对象并调用eat()方法
|
|
|
/********* begin *********/
|
|
|
Animal a=new Dog();
|
|
|
a.eat();
|
|
|
Animal b=new Cat();
|
|
|
b.eat();
|
|
|
Animal c=new Lion();
|
|
|
c.eat();
|
|
|
/********* end *********/
|
|
|
}
|
|
|
}
|
|
|
|
|
|
// Animal类中定义eat()方法
|
|
|
abstract class Animal {
|
|
|
/********* begin *********/
|
|
|
abstract void eat();
|
|
|
/********* end *********/
|
|
|
}
|
|
|
|
|
|
// Dog类继承Animal类 复写eat()方法
|
|
|
class Dog extends Animal {
|
|
|
/********* begin *********/
|
|
|
public void eat(){
|
|
|
System.out.println("eating bread...");
|
|
|
}
|
|
|
/********* end *********/
|
|
|
}
|
|
|
|
|
|
// Cat类继承Animal类 复写eat()方法
|
|
|
class Cat extends Animal {
|
|
|
/********* begin *********/
|
|
|
public void eat(){
|
|
|
System.out.println("eating rat...");
|
|
|
}
|
|
|
/********* end *********/
|
|
|
}
|
|
|
|
|
|
// Lion类继承Animal类 复写eat()方法
|
|
|
class Lion extends Animal {
|
|
|
/********* begin *********/
|
|
|
public void eat(){
|
|
|
System.out.println("eating meat...");
|
|
|
}
|
|
|
/********* end *********/
|
|
|
}
|
