Java Inheritance - calling superclass method

问题

Lets suppose I have the following two classes

public class alpha {

    public alpha(){
        //some logic
    }

    public void alphaMethod1(){
        //some logic
    }
}

public class beta extends alpha {

    public beta(){
        //some logic
    }

    public void alphaMethod1(){
        //some logic
    }
}

public class Test extends beta
{
     public static void main(String[] args)
      {
        beta obj = new beta();
        obj.alphaMethod1();// Here I want to call the method from class alpha.
       }
}

If I initiate a new object of type beta, how can I execute the alphamethod1 logic found in class alpha rather than beta? Can I just use super().alphaMethod1() <- I wonder if this is possible.

Autotype in Eclipse IDE is giving me the option to select alphamethod1 either from class alpha or class beta.

回答1:

You can do:

super.alphaMethod1();

Note, that super is a reference to the parent, but super() is it's constructor.

回答2:

Simply use super.alphaMethod1();

See super keyword in java

回答3:

You can't call alpha's alphaMethod1() by using beta's object But you have two solutions:

solution 1: call alpha's alphaMethod1() from beta's alphaMethod1()

class Beta extends Alpha
{
  public void alphaMethod1()
  {
    super.alphaMethod1();
  }
}

or from any other method of Beta like:

class Beta extends Alpha
{
  public void foo()
  {
     super.alphaMethod1();
  }
}

class Test extends Beta 
{
   public static void main(String[] args)
   {
      Beta beta = new Beta();
      beta.foo();
   }
}

solution 2: create alpha's object and call alpha's alphaMethod1()

class Test extends Beta
{
   public static void main(String[] args)
   {
      Alpha alpha = new Alpha();
      alpha.alphaMethod1();
   }
}

回答4:

It is possible to use super to call the method from mother class, but this would mean you probably have a design problem. Maybe B.alphaMethod1() shouldn't override A's method and be called B.betaMethod1().

If it depends on the situation, you can put some code logic like :

public void alphaMethod1(){
    if (something) {
        super.alphaMethod1();
        return;
    }
    // Rest of the code for other situations
}

Like this it will only call A's method when needed and will remain invisible for the class user.

回答5:

Whenever you create child class object then that object has all the features of parent class. Here Super() is the facilty for accession parent.

If you write super() at that time parents's default constructor is called. same if you write super.

this keyword refers the current object same as super key word facilty for accessing parents.

来源：https://stackoverflow.com/questions/6896504/java-inheritance-calling-superclass-method

标签

java

inheritance

methods

superclass