在Java中,继承和多态是面向对象编程的两个重要特性。它们可以帮助我们更好地组织和管理代码,提高代码的可重用性和可扩展性。下面是一个关于Employee类的继承和多态应用的例子:
public class Employee {
private String name;
private int age;
private double salary;
public Employee(String name, int age, double salary) {
this.name = name;
this.age = age;
this.salary = salary;
}
public void work() {
System.out.println("Employee is working...");
}
// Getter and Setter methods
}
public class Manager extends Employee {
private List<Employee> subordinates;
public Manager(String name, int age, double salary) {
super(name, age, salary);
this.subordinates = new ArrayList<>();
}
public void manage() {
System.out.println("Manager is managing...");
}
public void addSubordinate(Employee employee) {
subordinates.add(employee);
}
// Other manager-specific methods
}
在这个例子中,Manager类继承了Employee类的属性和方法。这意味着Manager对象可以访问和使用Employee类的所有属性和方法。同时,Manager类还有自己独特的属性(如subordinates)和方法(如manage()和addSubordinate())。
public class Programmer extends Employee {
private String programmingLanguage;
public Programmer(String name, int age, double salary, String programmingLanguage) {
super(name, age, salary);
this.programmingLanguage = programmingLanguage;
}
public void code() {
System.out.println("Programmer is coding in " + programmingLanguage);
}
// Other programmer-specific methods
}
多态允许我们将子类对象当作父类对象来处理。这意味着我们可以在不了解具体类型的情况下,使用父类引用来调用子类的方法。例如:
public static void main(String[] args) {
Employee employee1 = new Manager("Alice", 30, 10000);
Employee employee2 = new Programmer("Bob", 25, 8000, "Java");
employee1.work(); // 输出 "Employee is working..."
employee2.work(); // 输出 "Employee is working..."
// 由于多态,我们可以将Manager和Programmer对象当作Employee对象来处理
if (employee1 instanceof Manager) {
Manager manager = (Manager) employee1;
manager.manage(); // 输出 "Manager is managing..."
}
if (employee2 instanceof Programmer) {
Programmer programmer = (Programmer) employee2;
programmer.code(); // 输出 "Programmer is coding in Java"
}
}
在这个例子中,我们可以看到多态的优势。我们可以使用Employee类型的引用来调用Manager和Programmer类的方法,而无需关心它们的具体类型。这使得我们的代码更加灵活和可扩展。