在Java中,繼承和多態(tài)是面向對象編程的兩個重要特性。它們可以幫助我們更好地組織和管理代碼,提高代碼的可重用性和可擴展性。下面是一個關于Employee類的繼承和多態(tài)應用的例子:
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
}
在這個例子中,Manager類繼承了Employee類的屬性和方法。這意味著Manager對象可以訪問和使用Employee類的所有屬性和方法。同時,Manager類還有自己獨特的屬性(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
}
多態(tài)允許我們將子類對象當作父類對象來處理。這意味著我們可以在不了解具體類型的情況下,使用父類引用來調用子類的方法。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(); // 輸出 "Employee is working..."
employee2.work(); // 輸出 "Employee is working..."
// 由于多態(tài),我們可以將Manager和Programmer對象當作Employee對象來處理
if (employee1 instanceof Manager) {
Manager manager = (Manager) employee1;
manager.manage(); // 輸出 "Manager is managing..."
}
if (employee2 instanceof Programmer) {
Programmer programmer = (Programmer) employee2;
programmer.code(); // 輸出 "Programmer is coding in Java"
}
}
在這個例子中,我們可以看到多態(tài)的優(yōu)勢。我們可以使用Employee類型的引用來調用Manager和Programmer類的方法,而無需關心它們的具體類型。這使得我們的代碼更加靈活和可擴展。