抽象類和繼承抽象類

抽象類不能直接例項化，需要建立一個指向自己的物件引用（其子類）來例項化
程式碼：

public class Main
{
    public static void main(String[] args)
    {
        /* People people = new People(); */ //錯誤
        People p = new Man();
        p.eat();
        p.drink();
        /* p.palyGames() */ //此方法錯誤
        Man man = new Man();
        man.eat();
        man.playGames();
        Women women = new
 
 Women();
        women.eat();
        women.dressing();
    }
    abstract static class People{
        String name;
        int age;
        float height;
        float weight;
        public void eat(){
            System.out.println("人都會吃飯");
        }
        public abstract void drink();
    }
    static
 
 class Man extends People{
        float short_hair;
        public void playGames(){
            System.out.println("男的獨有的打遊戲技能");
        }
        @Override
        public void drink(){
            System.out.println("man drink 酒");
        }
    }
    static class Women extends People{
        float
 
 long_hair;
        public void dressing(){
            System.out.println("女的獨有的化妝技能");
        }
        @Override
        public void drink(){
            System.out.println("women drink 飲料");
        }
    }
}

這裡People不能直接例項化，如果是People p = new Man();這裡p只能呼叫People類n抽象方法和成果呼叫了其抽象方法，則訪問的是其引用類（子類）繼承的抽象類；如果是Man man= new Man();這裡man是可以呼叫類Man和其繼承的抽象類People的方法和屬性