面向对象之多态参数

定义员工类Employee，包含姓名和月工资[private]，以及计算年工资getAnnual方法。普通员工和经理继承了员工，经理类多了奖金bonus属性和管理manage方去，普通员工类多了work方法，普通员工和经理类要求分别重写getAnnual方法则试类中添加一个方法showEmpAnnual(Employee e)，实现获取任何员工对象的丰工资,并在main方法中调用该方法[e.getAnnual0]
试类中添加一个方法，testWork,如果是普通员工，则调用work方法，如果是经里，则调用manage方法
类Employee

package poly_polyparameter;

public class Employee {
    private String name;
    private double salary;

    public Employee(String name, double salary) {
        this.name = name;
        this.salary = salary;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public double getSalary() {
        return salary;
    }

    public void setSalary(double salary) {
        this.salary = salary;
    }
    public double getAnnul() {
        return 12 * this.salary;
    }
}

普通员工类

package poly_polyparameter;

public class Worker extends Employee{
    public Worker(String name, double salary) {
        super(name, salary);
    }
    public void work() {
        System.out.println("普通员工" + this.getName() + "正在工作");
    }

    @Override
    public double getAnnul() {
        return super.getAnnul();
    }
}

经理类

package poly_polyparameter;

public class Manager extends Employee {
    private double bonous;//奖金

        public Manager(String name, double salary) {
                super(name, salary);
        }

        public Manager(String name, double salary, double bonous) {
                super(name, salary);
                this.bonous = bonous;
        }

        @Override
        public double getAnnul() {
                return super.getAnnul() + this.bonous;
        }
        public void manage() {
                System.out.println("经理" + this.getName() + "正在管理");
        }
        public double getBonous() {
                return bonous;
        }

        public void setBonous(double bonous) {
                this.bonous = bonous;
        }
}

主函数

import poly_polyparameter.Employee;
import poly_polyparameter.Manager;
import poly_polyparameter.Worker;

public class Main {
    public static void main(String[] args) {
        Worker tom = new Worker("tom", 2500);
        Manager milan = new Manager("milan", 5000, 200000);
        Main main = new Main();
        main.showEmpAnuul(tom);
        main.showEmpAnuul(milan);
        main.testWork(tom);
        main.testWork(milan);


    }

    //实现获取任何员工对象的年工资,并在 main 方法中调用该方法 [e.getAnnual()]
    public void showEmpAnuul(Employee e) {
        System.out.println(e.getAnnul());//动态绑定机制
    }
    //添加一个方法，testWork,如果是普通员工，则调用 work 方法，如果是经理，则调用 manage 方法
    public void testWork(Employee e) {
        if (e instanceof Worker) {
            ((Worker) e).work();//向下转型
        } else if (e instanceof Manager) {
            ((Manager) e).manage();
        }else {
            System.out.println("不能处理...");
        }
    }
}

编译结果

总结

多态参数总的来说还是要运行instanceof判断是否需要的类，是的话通过向下转型使用子类方法