static
如代码示例:
代码中直接对调用类名进行赋值,该类的所有对象的university成员都为“传智大学”了,不用再一一赋值。
static的访问特点
多态
多态中成员访问特点
多态的好处与弊端
多态中的转型
如示例代码:
多态的代码案例示例:猫和狗
//Animal
package com;
public class Animal {
private String name;
private int age;
public Animal() {
}
public Animal(String name, int age) {
this.name = name;
this.age = 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 eat(){
System.out.println("动物吃东西");
}
}
//AnimalDemo
package com;
public class AnimalDemo {
public static void main(String[] args) {
Animal a=new Cat();
a.setName("加菲");
a.setAge(5);
System.out.println(a.getName()+","+a.getAge());
a.eat();
a=new Cat("加菲",5);
System.out.println(a.getName()+","+a.getAge());
a.eat();
Animal b=new Dog();
b.setName("旺旺");
b.setAge(6);
System.out.println(b.getName()+","+b.getAge());
b.eat();
b=new Dog("旺旺",6);
System.out.println(b.getName()+","+b.getAge());
b.eat();
}
}
//Cat
package com;
public class Cat extends Animal {
public Cat(){
}
public Cat(String name,int age){
super(name,age);
}
@Override
public void eat() {
System.out.println("猫吃鱼");
}
}
//Dog
package com;
public class Dog extends Animal {
public Dog() {
}
public Dog(String name, int age) {
super(name, age);
}
@Override
public void eat() {
System.out.println("狗吃骨头");
}
}