如何实现这些超类方法？

Question

我应该做的： 编写一个 java 程序来展示继承概念，其中 Employee 是超类，Manager 是子类。遵循以下类结构： - 员工类

变量：

1. 员工编号
2. 员工姓名
3. 员工工资

Constructor - 使用它来初始化函数上面的所有变量

Display() – This displays all the 3 variable values.
setSalary() – This sets the salary variable.
getSalary() – This gets the salary variable.

这就是我目前所拥有的

public class Employee {
    private int employeeNumber;
    private String employeeName;
    private double employeeSalary;

    public Employee(int employeeNumber, String employeeName, double employeeSalary) {
    this.employeeNumber = employeeNumber;
    this.employeeName = employeeName;
    this.employeeSalary = employeeSalary;
    }
}

我的问题是如何实现这三种方法？ 他们只是标准的getter和setter吗？ 我不熟悉显示功能，如果有人可以帮忙 谢谢！

Answer 1

你真的很亲密。您需要创建经理类并扩展员工类。但首先让我们添加描述的方法来设置工资和显示所有字段！

员工类： display() 方法将字段连接在一起，按行分隔。

public class Employee {

    private int employeeNumber;
    private String employeeName;
    private double employeeSalary;

    public Employee(int employeeNumber, String employeeName, double employeeSalary){
        this.employeeNumber=employeeNumber;
        this.employeeName=employeeName;
        this.employeeSalary=employeeSalary;
    }


    public void display(){
        System.out.println("Employee Number: "+ employeeNumber +"\n"
                + "Employee Name: " + employeeName + "\n" 
                + "Employee Salary: "  + employeeSalary);
    }

    public double getEmployeeSalary() {
        return employeeSalary;
    }

    public void setEmployeeSalary(double employeeSalary) {
        this.employeeSalary = employeeSalary;
    }

}

经理类：根据一般知识，我假设经理也可以有多个员工。 因此，在此类中，您将拥有经理的特定方法，例如添加新员工，或显示为给定经理工作的员工。

public class Manager extends Employee {


    List<Employee> subordinates;
    public Manager(int employeeNumber, String employeeName, double employeeSalary) {
        super(employeeNumber, employeeName, employeeSalary);
        subordinates = new ArrayList<>();
    }


    public void displayEmployees(){
        for(Employee employee: subordinates){
            employee.display();

            // just print an empty line - so its prettier
            System.out.println();
        }
    }

    public void addNewEmployee(Employee employee){
        subordinates.add(employee);
    }

    public List<Employee> getSubordinates() {
        return subordinates;
    }

    public void setSubordinates(List<Employee> subordinates) {
        this.subordinates = subordinates;
    }
}

测试：请注意，Manager 继承了 Employee 类的所有方法，这就是为什么在 Manager 类中不需要重写方法，但当然可以这样做添加新功能。

public class Main {

    public static void main(String[] args) {

        Manager manager = new Manager(11111, "Elon Musk", 42344);
        manager.display();


        // lets make some employees who work for the above manager

        Employee employeeOne = new Employee(324, "Bob Den", 3522);
        Employee employeeTwo = new Employee(44, "Tim Pipe", 4234 );
        Employee employeeThree = new Employee(42, "Asif Blar", 4321);

        // lets add the new employees to the managers list of employees ( this can further be refactored )

        manager.addNewEmployee(employeeOne);
        manager.addNewEmployee(employeeTwo);
        manager.addNewEmployee(employeeThree);

        // lets display all the employees who work for the manager
        manager.displayEmployees();


        // lets give the manager a 10 % raise
        double employeeSalary = manager.getEmployeeSalary();
        manager.setEmployeeSalary(employeeSalary +(employeeSalary /10));

        // lets print out the managers hefty new salary
        manager.display();

    }
}