2.设计电话薄程序，根据下列描述设计类层次关系。 （1）联系人信息有：姓名、电话、备注；家人信息：还包括地址、固定电话； 朋友信息：还包括类别（同学、同事、其他朋友）； （2）工作联系人信息：还包括公司、部门、职务。 （3）注重重写toString（），返回每类对象的全部信息 （4）要求在父亲中定义display（）方法，此方法中将toString（）结果输出值控台 （5）提供添加、删除、修改、查看指定成员、查看所有联系人信息等方法写出一个可运行的java代码

以下是一个简单的电话薄程序的Java代码实现：

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class PhoneBook {
    private List<Contact> contacts;

    public PhoneBook() {
        contacts = new ArrayList<>();
    }

    public void addContact(Contact contact) {
        contacts.add(contact);
    }

    public void removeContact(int index) {
        if (index >= 0 && index < contacts.size()) {
            contacts.remove(index);
        }
    }

    public void modifyContact(int index, Contact contact) {
        if (index >= 0 && index < contacts.size()) {
            contacts.set(index, contact);
        }
    }

    public Contact getContact(int index) {
        if (index >= 0 && index < contacts.size()) {
            return contacts.get(index);
        }
        return null;
    }

    public List<Contact> getAllContacts() {
        return contacts;
    }

    public void display() {
        for (Contact contact : contacts) {
            System.out.println(contact.toString());
        }
    }

    public static void main(String[] args) {
        PhoneBook phoneBook = new PhoneBook();
        Scanner scanner = new Scanner(System.in);
        int choice = 0;
        do {
            System.out.println("请选择操作：");
            System.out.println("1. 添加联系人");
            System.out.println("2. 删除联系人");
            System.out.println("3. 修改联系人");
            System.out.println("4. 查看指定联系人");
            System.out.println("5. 查看所有联系人信息");
            System.out.println("6. 退出程序");
            System.out.print("请输入操作编号：");
            choice = scanner.nextInt();
            scanner.nextLine();
            switch (choice) {
                case 1:
                    System.out.print("请输入联系人类型（1：家人，2：朋友，3：工作联系人）：");
                    int type = scanner.nextInt();
                    scanner.nextLine();
                    Contact contact = null;
                    switch (type) {
                        case 1:
                            System.out.print("请输入姓名：");
                            String name = scanner.nextLine();
                            System.out.print("请输入电话：");
                            String phone = scanner.nextLine();
                            System.out.print("请输入备注：");
                            String remark = scanner.nextLine();
                            System.out.print("请输入地址：");
                            String address = scanner.nextLine();
                            System.out.print("请输入固定电话：");
                            String fixedPhone = scanner.nextLine();
                            contact = new Family(name, phone, remark, address, fixedPhone);
                            break;
                        case 2:
                            System.out.print("请输入姓名：");
                            name = scanner.nextLine();
                            System.out.print("请输入电话：");
                            phone = scanner.nextLine();
                            System.out.print("请输入备注：");
                            remark = scanner.nextLine();
                            System.out.print("请输入类别（同学、同事、其他朋友）：");
                            String category = scanner.nextLine();
                            contact = new Friend(name, phone, remark, category);
                            break;
                        case 3:
                            System.out.print("请输入姓名：");
                            name = scanner.nextLine();
                            System.out.print("请输入电话：");
                            phone = scanner.nextLine();
                            System.out.print("请输入备注：");
                            remark = scanner.nextLine();
                            System.out.print("请输入公司：");
                            String company = scanner.nextLine();
                            System.out.print("请输入部门：");
                            String department = scanner.nextLine();
                            System.out.print("请输入职务：");
                            String position = scanner.nextLine();
                            contact = new WorkContact(name, phone, remark, company, department, position);
                            break;
                        default:
                            System.out.println("输入有误，请重新输入！");
                            break;
                    }
                    if (contact != null) {
                        phoneBook.addContact(contact);
                        System.out.println("添加成功！");
                    }
                    break;
                case 2:
                    System.out.print("请输入要删除的联系人编号：");
                    int index = scanner.nextInt();
                    scanner.nextLine();
                    phoneBook.removeContact(index);
                    System.out.println("删除成功！");
                    break;
                case 3:
                    System.out.print("请输入要修改的联系人编号：");
                    index = scanner.nextInt();
                    scanner.nextLine();
                    System.out.print("请输入联系人类型（1：家人，2：朋友，3：工作联系人）：");
                    type = scanner.nextInt();
                    scanner.nextLine();
                    switch (type) {
                        case 1:
                            System.out.print("请输入姓名：");
                            String name = scanner.nextLine();
                            System.out.print("请输入电话：");
                            String phone = scanner.nextLine();
                            System.out.print("请输入备注：");
                            String remark = scanner.nextLine();
                            System.out.print("请输入地址：");
                            String address = scanner.nextLine();
                            System.out.print("请输入固定电话：");
                            String fixedPhone = scanner.nextLine();
                            Contact newContact = new Family(name, phone, remark, address, fixedPhone);
                            phoneBook.modifyContact(index, newContact);
                            break;
                        case 2:
                            System.out.print("请输入姓名：");
                            name = scanner.nextLine();
                            System.out.print("请输入电话：");
                            phone = scanner.nextLine();
                            System.out.print("请输入备注：");
                            remark = scanner.nextLine();
                            System.out.print("请输入类别（同学、同事、其他朋友）：");
                            String category = scanner.nextLine();
                            newContact = new Friend(name, phone, remark, category);
                            phoneBook.modifyContact(index, newContact);
                            break;
                        case 3:
                            System.out.print("请输入姓名：");
                            name = scanner.nextLine();
                            System.out.print("请输入电话：");
                            phone = scanner.nextLine();
                            System.out.print("请输入备注：");
                            remark = scanner.nextLine();
                            System.out.print("请输入公司：");
                            String company = scanner.nextLine();
                            System.out.print("请输入部门：");
                            String department = scanner.nextLine();
                            System.out.print("请输入职务：");
                            String position = scanner.nextLine();
                            newContact = new WorkContact(name, phone, remark, company, department, position);
                            phoneBook.modifyContact(index, newContact);
                            break;
                        default:
                            System.out.println("输入有误，请重新输入！");
                            break;
                    }
                    System.out.println("修改成功！");
                    break;
                case 4:
                    System.out.print("请输入要查看的联系人编号：");
                    index = scanner.nextInt();
                    scanner.nextLine();
                    Contact targetContact = phoneBook.getContact(index);
                    if (targetContact != null) {
                        System.out.println(targetContact.toString());
                    } else {
                        System.out.println("联系人不存在！");
                    }
                    break;
                case 5:
                    phoneBook.display();
                    break;
                case 6:
                    System.out.println("退出程序，再见！");
                    break;
                default:
                    System.out.println("输入有误，请重新输入！");
                    break;
            }
        } while (choice != 6);
        scanner.close();
    }
}

class Contact {
    protected String name;
    protected String phone;
    protected String remark;

    public Contact(String name, String phone, String remark) {
        this.name = name;
        this.phone = phone;
        this.remark = remark;
    }

    @Override
    public String toString() {
        return "姓名：" + name + "，电话：" + phone + "，备注：" + remark;
    }
}

class Family extends Contact {
    private String address;
    private String fixedPhone;

    public Family(String name, String phone, String remark, String address, String fixedPhone) {
        super(name, phone, remark);
        this.address = address;
        this.fixedPhone = fixedPhone;
    }

    @Override
    public String toString() {
        return super.toString() + "，地址：" + address + "，固定电话：" + fixedPhone;
    }
}

class Friend extends Contact {
    private String category;

    public Friend(String name, String phone, String remark, String category) {
        super(name, phone, remark);
        this.category = category;
    }

    @Override
    public String toString() {
        return super.toString() + "，类别：" + category;
    }
}

class WorkContact extends Contact {
    private String company;
    private String department;
    private String position;

    public WorkContact(String name, String phone, String remark, String company, String department, String position) {
        super(name, phone, remark);
        this.company = company;
        this.department = department;
        this.position = position;
    }

    @Override
    public String toString() {
        return super.toString() + "，公司：" + company + "，部门：" + department + "，职务：" + position;
    }
}