Java继承:在超类中调用子类方法

问题描述：

我对Java很陌生，想知道是否可以在超类中调用子类方法.如果要进行继承，在哪里设置 public static void main .

I'm very new to java and would like to know whether calling a subclass method in a superclass is possible. And if doing inheritance, where is the proper place to set public static void main.

超类

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);

    }

}

答

我对Java很陌生，想知道是否调用子类超类中的方法是可能的.

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

超类对其子类一无所知，因此，您不能在超类中调用子类 instance 方法.

A superclass doesn't know anything about their subclasses, therefore, you cannot call a subclass instance method in a super class.

在哪里设置公共static void main的适当位置.

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

由于许多因素，我不建议将main方法放在Admin类或User类中.而是创建一个单独的类来封装main方法.

I wouldn't recommend putting the main method in the Admin class nor the User class for many factors. Rather create a separate class to encapsulate the main method.

示例:

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

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

Java继承:在超类中调用子类方法

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