Java 继承 : Calling a subclass method in a superclass

Question

我对java很陌生，想知道是否可以在父类(super class)中调用子类方法。如果进行继承，那么设置 public static void main 的合适位置在哪里。

父类(super class)

public class User {
    private String name;
    private int age;

    public User() {
        //Constructor
    }

    //Overloaded constructor
    public User(String name, int age) {
        this.name = name; 
        this.age = age;
    }

    public String getName() {
        return this.name;
    }
    public static void main(String []args) {
        User user1 = new Admin("Bill", 18, 2); 

        System.out.println("Hello "+user1.getName()); 
        user1.getLevel();
    }

}

子类

public class Admin extends User {

    private int permissionLevel;

    public Admin() {
    //Constructor 
    }

    //Overloading constructor
    public Admin(String name, int age, int permissionLevel) {
        super(name, age); 
        this.permissionLevel = permissionLevel;
    }

    public void getLevel() {
        System.out.println("Hello "+permissionLevel);

    }

}

Answer 1

I'm very new to java and would like to know whether calling a subclass method in a superclass is possible.

父类(super class)对其子类一无所知，因此，您不能在父类(super class)中调用子类实例方法。

where is the proper place to set public static void main.

我不建议将 main Admin 中的方法类也不是User类的许多因素。而是创建一个单独的类来封装 main方法。

例子:

public class Main{
   public static void main(String []args) {
        User user1 = new Admin("Bill", 18, 2); 

        System.out.println("Hello "+user1.getName()); 
        user1.getLevel();
    }
}