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【Java学习笔记】多态参数

java 2025/5/13 7:59:59

多态参数

应用：方法定义的形参类型为父类类型，实参允许为子类类型

// 父类
package polyparemeter;public class employee {private String name;private double salary;//构造器public employee(){}public employee(String name, double salary) {this.name = name;this.salary = salary;}public double getannual(){return 12 * salary;}public String getName() {return name;}//多态参数的体现，可以接收子类对象//父类独有的方法，返回员工工资public void showannual(employee e){System.out.println(e);System.out.println(e.getannual());//增加判断调用独有的方法System.out.println("\n接着使用instanceof操作符判断，调用独有的方法");if(e instanceof manager){manager mag = (manager) e;mag.manage();}else if(e instanceof worker){worker wok = (worker) e;wok.work();}}
}// 子类
package polyparemeter;public class manager extends employee{private double bonus;//构造器public manager(String name, double salary, double bonus) {super(name, salary);this.bonus = bonus;}// manage类独有的方法manage（）public void manage(){System.out.println("经理 "  + getName() + " is managing");}//重写父类的getannual（）方法public double getannual(){return super.getannual() + bonus;}
}package polyparemeter;public class worker extends employee {public worker(String name, double salary) {super(name, salary);}//worker类独有的方法public void work(){System.out.println("普通员工 " + getName() + " is working");}}// 主类
package polyparemeter;public class main {public static void main(String[] args) {worker tom = new worker("tom",2500);manager smith = new manager("smith",2500,5000);employee e = new employee();e.showannual(tom);System.out.println("==============================");e.showannual(smith);}
}// 运行结果
polyparemeter.worker@4554617c
30000.0接着使用instanceof操作符判断，调用独有的方法
普通员工 tom is working
==============================
polyparemeter.manager@74a14482
35000.0接着使用instanceof操作符判断，调用独有的方法
经理 smith is managin