java抽象类创建入门

1 动物抽象类Animal.javapackage com.liuyi_02;/*** 这是动物抽象类**/public abstract class Animal {/*** 这是吃饭的功能*/public abstract void eat();/*** 这是睡觉的功能*/public abstract void sleep();}Cat.javapackage com.liuyi_02;/*** 这是具体的猫类**/public class Cat extends Animal {@Overridepublic void eat() {System.out.println("猫吃鱼");}@Overridepublic void sleep() {System.out.println("猫趴着睡觉");}}Dog.javapackage com.liuyi_02;import com.liuyi_01.Jump;/*** 这是具体的狗类**/public class Dog extends Animal implements Jump { @Overridepublic void jump() {System.out.println("会跳高的狗");}@Overridepublic void eat() {System.out.println("狗吃肉");}@Overridepublic void sleep() {System.out.println("狗站着睡觉");}}package com.liuyi_01;/*** 这是跳高接口**/public interface Jump {/*** 这是跳高功能*/public abstract void jump();}2 HelloWorld.javapackage cn.itcast_01;public class HelloWorld {/*** @param args*/public static void main(String[] args) {// TODO Auto-generated method stubSystem.out.println("HelloWorld");System.out.println("aaaa");int a;}}3 Student.javapackage cn.itcast_02;public class Student {private String name;private int age;public int num = 10;public final int num22 = 20;public static int num3 = 30;public static final int num4 = 40;public Student() {}public void setName(String name) { = name;}public String getName() {return name;}public void setAge(int age) {this.age = age;}public int getAge() {return age;}}4 Dom.javapackage cn.itcast_03;import cn.itcast_01.HelloWorld;/** alt+/ 内容辅助键** A:main方法* main+alt+/ 回车即可* B:输出语句* syso+alt+/* C:提示作用* 帮助你补齐一些你你不住的东西，还可以帮你起名字等。

*/public class Demo {// public static void main(String[] args) {// System.out.println("HelloWorld");// }public static void main(String[] args) {System.out.println();String string = new String();HelloWorld helloWorld = new HelloWorld();}}package cn.itcast_03;import java.util.ArrayList;import java.util.Date;import java.util.Scanner;/** 常用快捷键* 1:格式化 ctrl+shift+f* 2：导入包 ctrl+shift+o* 如果该类仅仅在一个包中有，就自己显示了* 如果该类在多个包中有，会弹出一个框框供你选择* 3:注释* 单行：注释 ctrl+/，取消注释再来一次。

* 多行：ctrl+shift+/,ctrl+shift+\* 4:代码上下移动* 选中代码alt+上/下箭头* 5:查看源码* 选中类名(F3或者Ctrl+鼠标点击)*/public class HelloWorld {public static void main(String[] args) {int a = 10;System.out.println(a);Scanner sc = new Scanner(System.in);Date d = new Date();// StringBuffer// ArrayList<E>Math.random();}}5 成员变量Student.javapackage cn.itcast_04;/** 提高开发效率：* A:帮助我们自动提供构造方法a:无参构造方法在代码区域右键--source--Generate Constructors from Superclassb:带参构造方法在代码区域右键--source--Generate Constructors using fields.. -- finishB:成对的getXxx()和setXxx()在代码区域右键--source--Generate Getters and Setters...*/public class Student {// 成员变量private String name;private int age;//构造方法public Student() {super();}public Student(String name, int age) { super(); = name;this.age = age;}//成员方法public String getName() {return name;}public void setName(String name) { = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}}Teacher.javapackage cn.itcast_04;public class Teacher {// 成员变量private String name;private int age;public Teacher(String name, int age) { super(); = name;this.age = age;}public Teacher() {super();// TODO Auto-generated constructor stub }public String getName() {return name;}public void setName(String name) { = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}}6 重写Animal.javapackage cn.itcast_05;public abstract class Animal {public abstract void eat();}Cat,javapackage cn.itcast_05;public class Cat extends Animal {@Overridepublic void eat() {System.out.println("猫吃鱼");}}Dog.javapackage cn.itcast_05;/** 是注解。

* 这个注解的意思是说，我这个方法是重写父类的。

* 如果和父类名出现了偏差就会报错。

*/public class Dog extends Animal {@Overridepublic void eat() {}public void sleep() {}}JUMP.javapackage cn.itcast_05;public interface Jump {public abstract void jump();}Pig.Javapackage cn.itcast_05;public class Pig extends Animal implements Jump { @Overridepublic void jump() {}@Overridepublic void eat() {}}7 创建对象Student.javapackage cn.itcast_01;public class Student {// 姓名private String name;// 年龄private int age;public Student(String name, int age) {super(); = name;this.age = age;}public Student() {super();}public String getName() {return name;}public void setName(String name) { = name;}public int getAge() {return age;}public void setAge(int age) {this.age = age;}public void show() {System.out.println("姓名：" + name + ",年龄:" + age);}}StudentDemo.javapackage cn.itcast_01;/** 测试类*/public class StudentDemo {public static void main(String[] args) {// 创建对象Student s1 = new Student();s1.setName("图图");s1.setAge(6);System.out.println(s1.getName() + "---" + s1.getAge());s1.show();// 创建对象Student s2 = new Student("小美", 7);System.out.println(s2.getName() + "---" + s2.getAge());s2.show();}}8 抽象类package cn.itcast_02;import com.liuyi_02.Animal;import com.liuyi_02.Cat;import com.liuyi_02.Dog;public class AnimalDemo {public static void main(String[] args) {// 抽象类不能实例化// Animal a = new Animal();Animal a = new Cat();a.eat();a.sleep();System.out.println("----------");a = new Dog();a.eat();a.sleep();System.out.println("----------");// 想使用跳高功能Dog d = (Dog) a;d.eat();d.sleep();d.jump();}}9 定义求和变量ArgsDemo.javapackage cn.itcast_03;/** 通过debug查看程序执行流程* 请大家也做一遍。