代码验证03

Posted 2020-12-01 zl00

1、Zoo1

public class Zoo
{

public static void main(String args[])
{

Feeder f = new Feeder("小李");

// 饲养员小李喂养一只狮子

f.feedLion(new Lion());

// 饲养员小李喂养十只猴子

for (int i = 0; i < 10; i++)
{

f.feedMonkey(new Monkey());

}

// 饲养员小李喂养5只鸽子

for (int i = 0; i < 5; i++)
{

f.feedPigeon(new Pigeon());

}

}

}

class Feeder
{

public String name;

public Feeder(String name)
{

this.name = name;

}

public void feedLion(Lion l)
{

l.eat();

}

public void feedPigeon(Pigeon p)
{

p.eat();

}

public void feedMonkey(Monkey m)
{

m.eat();

}

}

class Lion
{

public void eat()
{

System.out.println("我不吃肉谁敢吃肉！");

}

}

class Monkey
{

public void eat()
{

System.out.println("我什么都吃，尤其喜欢香蕉。");

}

}

class Pigeon
{

public void eat()
{

System.out.println("我要减肥，所以每天只吃一点大米。");

}

}

 

 

2、Zoo2

public class Zoo
{

public static void main(String args[])
{

Feeder f = new Feeder("小李");

//饲养员小李喂养一只狮子

f.feedAnimal(new Lion());
//饲养员小李喂养十只猴子

for (int i = 0; i < 10; i++)
{

f.feedAnimal(new Monkey());

}

//饲养员小李喂养5只鸽子

for (int i = 0; i < 5; i++)
{

f.feedAnimal(new Pigeon());

}

}

}

class Feeder
{

public String name;

Feeder(String name)
{

this.name = name;

}

public void feedAnimal(Animal an)
{

an.eat();

}

}

abstract class Animal
{

public abstract void eat();

}

class Lion extends Animal
{

public void eat()
{

System.out.println("我不吃肉谁敢吃肉！");

}

}

class Monkey extends Animal
{

public void eat()
{

System.out.println("我什么都吃，尤其喜欢香蕉。");

}

}

class Pigeon extends Animal
{

public void eat()
{

System.out.println("我要减肥，所以每天只吃一点大米。");

}

}

 

 

3、Zoo3

package zoo3;

public class Zoo {

public static void main(String args[]) {
Feeder f = new Feeder("小李");
Animal[] ans = new Animal[16];

//饲养员小李喂养一只狮子
ans[0] = new Lion();
//饲养员小李喂养十只猴子
for (int i = 0; i < 10; i++) {
ans[1 + i] = new Monkey();
}
//饲养员小李喂养5只鸽子
for (int i = 0; i < 5; i++) {
ans[11 + i] = new Pigeon();
}

f.feedAnimals(ans);
}
}

class Feeder {

public String name;

Feeder(String name) {
this.name = name;
}

public void feedAnimals(Animal[] ans) {
for (Animal an : ans) {
an.eat();
}
}
}

abstract class Animal {

public abstract void eat();
}

class Lion extends Animal {

public void eat() {
System.out.println("我不吃肉谁敢吃肉！");
}
}

class Monkey extends Animal {

public void eat() {
System.out.println("我什么都吃，尤其喜欢香蕉。");
}
}

class Pigeon extends Animal {

public void eat() {
System.out.println("我要减肥，所以每天只吃一点大米。");
}
}

 

 

4、Zoo4

import java.util.Vector;

public class Zoo {

public static void main(String args[]) {
Feeder f = new Feeder("小李");
Vector<Animal> ans = new Vector<Animal>();

//饲养员小李喂养一只狮子
ans.add(new Lion());
//饲养员小李喂养十只猴子
for (int i = 0; i < 10; i++) {
ans.add(new Monkey());
}
//饲养员小李喂养5只鸽子
for (int i = 0; i < 5; i++) {
ans.add(new Pigeon());
}
f.feedAnimals(ans);
}
}

class Feeder {

public String name;

Feeder(String name) {
this.name = name;
}

public void feedAnimals(Vector<Animal> ans) {
for (Animal an : ans) {
an.eat();
}
}
}

abstract class Animal {

public abstract void eat();
}

class Lion extends Animal {

public void eat() {
System.out.println("我不吃肉谁敢吃肉！");
}
}

class Monkey extends Animal {

public void eat() {
System.out.println("我什么都吃，尤其喜欢香蕉。");
}
}

class Pigeon extends Animal {

public void eat() {
System.out.println("我要减肥，所以每天只吃一点大米。");
}
}

 

 

5、Address

public final class Address
{
private final String detail;
private final String postCode;

//在构造方法里初始化两个实例属性
public Address()
{
this.detail = "";
this.postCode = "";

}
public Address(String detail , String postCode)
{
this.detail = detail;
this.postCode = postCode;
}
//仅为两个实例属性提供getter方法
public String getDetail()
{
return this.detail;
}

public String getPostCode()
{
return this.postCode;
}
//重写equals方法，判断两个对象是否相等。
public boolean equals(Object obj)
{
if (obj instanceof Address)
{
Address ad = (Address)obj;
if (this.getDetail().equals(ad.getDetail()) && this.getPostCode().equals(ad.getPostCode()))
{
return true;
}
}
return false;
}
public int hashCode()
{
return detail.hashCode() + postCode.hashCode();
}
}

 

 

6、ExplorationJDKSource

public class ExplorationJDKSource {

/**
* @param args
*/
public static void main(String[] args) {
System.out.println(new A());
}

}

class A{}

 

 

7、Fruit

public class Fruit
{

public String toString()
{
return "Fruit toString.";
}

public static void main(String args[])
{
Fruit f=new Fruit();
System.out.println("f="+f);
// System.out.println("f="+f.toString());
}
}

 

 

8、ParentChildTest

public class ParentChildTest {
public static void main(String[] args) {
Parent parent=new Parent();
parent.printValue();
Child child=new Child();
child.printValue();

parent=child;
parent.printValue();

parent.myValue++;
parent.printValue();

((Child)parent).myValue++;
parent.printValue();

}
}

class Parent{
public int myValue=100;
public void printValue() {
System.out.println("Parent.printValue(),myValue="+myValue);
}
}
class Child extends Parent{
public int myValue=200;
public void printValue() {
System.out.println("Child.printValue(),myValue="+myValue);
}
}

 

 

9、TestCast

class Mammal{}
class Dog extends Mammal {}
class Cat extends Mammal{}

public class TestCast
{
public static void main(String args[])
{
Mammal m;
Dog d=new Dog();
Cat c=new Cat();
m=d;
//d=m;
d=(Dog)m;
//d=c;
//c=(Cat)m;

}
}

 

 

10、TestInherits

class Grandparent
{

public Grandparent()
{

System.out.println("GrandParent Created.");

}

public Grandparent(String string)
{

System.out.println("GrandParent Created.String:" + string);

}

}

 

class Parent extends Grandparent
{

public Parent()
{

//super("Hello.Grandparent.");

System.out.println("Parent Created");

// super("Hello.Grandparent.");

}

}

 

class Child extends Parent
{

public Child()
{

System.out.println("Child Created");

}

}

 

public class TestInherits
{

public static void main(String args[])
{

Child c = new Child();

}

}

 

 

11、TestInstanceof

public class TestInstanceof
{
public static void main(String[] args)
{
//声明hello时使用Object类，则hello的编译类型是Object，Object是所有类的父类
//但hello变量的实际类型是String
Object hello = "Hello";
//String是Object类的子类，所以返回true。
System.out.println("字符串是否是Object类的实例：" + (hello instanceof Object));
//返回true。
System.out.println("字符串是否是String类的实例：" + (hello instanceof String));
//返回false。
System.out.println("字符串是否是Math类的实例：" + (hello instanceof Math));
//String实现了Comparable接口，所以返回true。
System.out.println("字符串是否是Comparable接口的实例：" + (hello instanceof Comparable));
String a = "Hello";
//String类既不是Math类，也不是Math类的父类，所以下面代码编译无法通过
//System.out.println("字符串是否是Math类的实例：" + (a instanceof Math));
}
}

 

 

12、TestPolimorphism

class Parent

{

public int value=100;

public void Introduce()
{

System.out.println("I‘m father");

}

}

class Son extends Parent
{

public int value=101;

public void Introduce()
{

System.out.println("I‘m son");

}

}

class Daughter extends Parent
{

public int value=102;
public void Introduce()
{

System.out.println("I‘m daughter");

}

}

public class TestPolymorphism
{

public static void main(String args[])
{

Parent p=new Parent();

p.Introduce();

System.out.println(p.value);

p=new Son();

p.Introduce();

System.out.println(p.value);

p=new Daughter();

p.Introduce();

System.out.println(p.value);

}

}