1、Animal（动物类-父类）

package cn.nnxy.animal;

public class Animal {
	private String name;
	private Integer legNum;
	public void shout() {
		System.out.print(name + "有" + legNum + "条腿" + "叫声");
	}
	public Animal(String name,Integer legNum) {
		setName(name);
		setLegNum(legNum);
	}
	
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public Integer getLegNum() {
		return legNum;
	}
	public void setLegNum(Integer legNum) {
		this.legNum = legNum;
	}
	
}

2、Cat（猫类-子类）

package cn.nnxy.animal;

public class Cat extends Animal{  //继承Animal父类


		
	public Cat(String name, Integer legNum) {
		super(name, legNum);
		setName(name);
		setLegNum(legNum);
	}

	public void shout() {
		System.out.print(getName() + "有" + getLegNum() + "条腿\n");
	}
}

3、Duck(鸭子类-子类)

package cn.nnxy.animal;

public class Duck extends Animal{
	
	
	
	public Duck(String name, Integer legNum) {
		super(name, legNum);
		setName(name);
		setLegNum(legNum);
	}

	public void shout() {
		System.out.print(getName() + "有" + getLegNum() + "条腿");
	}

}

4、测试类

package test;

import cn.nnxy.animal.Animal;
import cn.nnxy.animal.Cat;
import cn.nnxy.animal.Duck;

public class Test {


	public static void main(String[] args) {
		
		Animal animal;
		animal = new Cat("猫", 4);
		animal.shout();		
		animal = new Duck("鸭子", 2);
		animal.shout();
	}

}

运行结果：