java - 子类的构造函数无法编译

Question

我有一个名为 Person 的抽象类和一个扩展 Person 的子类，名为 Employee。当我尝试编译时，出现构造函数错误。如何在 Employee 类中编写构造函数以便编译？如果您需要有关此问题的更多信息，请告诉我。谢谢。

public abstract class Person {    //Person abstract class
   public String firstName;
   public String lastName;
   public char gender;

   public Person(String fname, String lname, char g) { //constructor
      firstName = fname;
      lastName = lname;
      gender = g;
   }
   public abstract void setDefaults();
}

public class Employee extends Person {   //Employee class that extends Person

   public Employee() {    //i thought super(); might solve the problem, but it didnt.
      super();
   }
   public void setDefaults() {}
}

Answer 1

您忘记将参数传递给 super() 声明。您的抽象构造函数需要参数。 super() 中的参数需要与父构造函数相同。可以使用不带任何参数的 super() 的唯一方法是，如果您的父构造函数根本没有任何参数。

public abstract class Person {    //Person abstract class
   public String firstName;
   public String lastName;
   public char gender;

   public Person(String fname, String lname, char g) { //constructor
      firstName = fname;
      lastName = lname;
      gender = g;
   }
   public abstract void setDefaults();
}

public class Employee extends Person {   //Employee class that extends Person

   public Employee(String fname, String lname, char g) {    //i thought super(); might solve the problem, but it didnt.
      super(fname, lname, g);
   }
   public void setDefaults() {}
}