java - java中使用super()，小时工方法

Question

我的一门类(class)遇到问题。除了 public HourlyEmployee(HourlyEmployee hourly) 下的 super(hourly) 之外，一切都很好。我不知道我是否使用了 super 错误或如何修复它。它只是说“实际和正式的论点长度不同。不确定这意味着什么。”谢谢

package payrollsystem_1;
import java.util.ArrayList;

public class HourlyEmployee extends Employee {
    private double hourlyRate;
    private double periodHours;

    public HourlyEmployee(int employeeID, String firstName, String lastName, 
            ArrayList<Paycheck> listOfPaychecks, double hourlyRate, double periodHours ){

        super(employeeID, firstName, lastName, listOfPaychecks);
        this.listOfPaychecks = listOfPaychecks;
        this.hourlyRate = hourlyRate;
        this.periodHours = periodHours;
    }

    public HourlyEmployee(HourlyEmployee hourly) {
       super(hourly);
        this.hourlyRate = hourly.hourlyRate;
        this.periodHours = hourly.periodHours;
    }

    public double getHourlyRate(){
        return hourlyRate;
    }

    public void setHourlyRate(double hourlyRate) {
        this.hourlyRate = hourlyRate;
    }

    public double getPeriodHours() {
        return periodHours;
    }

    public void setPeriodHours(double periodHours) {
        this.periodHours = periodHours;
    }

}

Answer 1

您需要确保 do There 有任何构造函数，例如

public Employee(HourlyEmployee hourly) {
  //I know the super class shouldn't know about the subclass.
  //But this is OK if you write like this.
  //It can be compiled without showing any errors.
  /*code*/
}

或

public Employee(Employee hourly) {
  /*code*/
}

在您的 Employee 类中。如果父类(super class)“Employee”没有像上面提到的两个那样的构造函数。当您尝试编译 HourlyEmployee.java 时，您将收到消息“实际参数和形式参数长度不同”。

这意味着您的父类(super class)“Employee”没有需要传递 HourlyEmployee 或其父类(super class)实例的构造函数。

事实上，您需要显示有关编译器错误消息的更多信息。我猜您得到了这样的信息。

HourlyEmployee.java:xx: error: constructor Employee in class Entity cannot be applied to the given types:
public Employee(int employeeID, String firstName, String lastName, ArrayList<Object> listOfPaychecks)
    required: int,String,String,ArrayList<Paycheck>
    found: HourlyEmployee
    reason: actual and formal argument lists differ in length