定义一个Person类和它的子类Employee。Person类有姓名、年龄和电话号码等私有成员变量，为私有成员变量分别定义set和get方法；定义一个方法showMessage()输出Person类的成员变量。Employee类有部门、工资等私有成员变量，定义一个方法showMessage()输出Employee的基本信息（含姓名、年龄和电话号码）。Person类和Employee类均定义带参和不带参的构造方法实现对其成员变量的初始化。定义一个public类，在其main()方法中分别基于父类和子类创建两个对象，通过构造方法分别为父类和子类的成员变量赋值，然后分别调用父类和子类的showMessage()方法输出其基本信息。使用java编写

在 Java 中，可以使用如下代码定义 Person 类和 Employee 类：

public class Person {
  private String name;
  private int age;
  private String phone;

  public Person() {
    // 默认构造方法
  }

  public Person(String name, int age, String phone) {
    this.name = name;
    this.age = age;
    this.phone = phone;
  }

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

  public String getName() {
    return name;
  }

  public void setAge(int age) {
    this.age = age;
  }

  public int getAge() {
    return age;
  }

  public void setPhone(String phone) {
    this.phone = phone;
  }

  public String getPhone() {
    return phone;
  }

  public void showMessage() {
    System.out.println("姓名: " + name + ", 年龄: " + age + ", 电话: " + phone);
  }
}

public class Employee extends Person {
  private String department;
  private double salary;

  public Employee() {
    // 默认构造方法
  }

  public Employee(String name, int age, String phone, String department, double salary) {
    super(name, age, phone);
    this.department = department;
    this.salary = salary;
  }

  public void setDepartment(String department) {
    this.department = department;
  }

  public String getDepartment() {
    return department;
  }

  public void setSalary(double salary) {
    this.salary = salary;
  }

  public double getSalary() {
    return salary;
  }

  public void showMessage() {
    super.showMessage();
    System.out.println("部门: " + department + ", 工资: " + salary);
  }
}

然后，可以在另一个 public 类中的 main 方法中创建 Person 类和 Employee 类的对象，并调用 showMessage 方法输出其基本信息：

public class Test {
  public static void main(String[] args) {
    Person p = new Person("张三", 25, "123456");
    p.showMessage();

    Employee e = new Employee("李四", 30, "654321", "市场部", 8000);
    e.showMessage();
  }
}

输出结果如下：

姓名: 张三, 年龄: 25, 电话: 123456