用Java实现2.某客户信息管理系统(CustomerInformationSystem)中保存着个人客户( IndividualCustomer)和企业客户(InstitutionalCustomer)两类信息，应用继承或接口编写程序实现以下要求: (1)个人客户。对于这类客户，系统保存了客户标识和基本信息，基本信息包括姓名、住宅电话和email。编写构造方法，并编写showInfo方法显示个人客户的信息。(2)企业客户。对于这类客户，系统除了保存客户标识和企业名称之外，也保存了其联系人的信息。联系人的信息包括姓名、住宅电话、email、办公电话以及职位。编写构造方法，并编写showInfo方法显示企业客户的信息。 (3)编写向系统中添加客户(addCustomer)的方法，并从键盘输入具体客户的信息(要求包括个人客户和企业客户)保存在某类集合(具体集合类自己选择)。 (4)编写从系统中输出客户(printCustomer)的方法，应用多态编程输出所有具体客户的信息。

以下是Java实现的代码，使用了继承和接口：

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

interface Customer {
    void showInfo();
}

class IndividualCustomer implements Customer {
    private String id;
    private String name;
    private String phone;
    private String email;

    public IndividualCustomer(String id, String name, String phone, String email) {
        this.id = id;
        this.name = name;
        this.phone = phone;
        this.email = email;
    }

    public void showInfo() {
        System.out.println("ID: " + id);
        System.out.println("Name: " + name);
        System.out.println("Phone: " + phone);
        System.out.println("Email: " + email);
    }
}

class ContactPerson {
    private String name;
    private String phone;
    private String email;
    private String officePhone;
    private String position;

    public ContactPerson(String name, String phone, String email, String officePhone, String position) {
        this.name = name;
        this.phone = phone;
        this.email = email;
        this.officePhone = officePhone;
        this.position = position;
    }

    public String getName() {
        return name;
    }

    public void showInfo() {
        System.out.println("Name: " + name);
        System.out.println("Phone: " + phone);
        System.out.println("Email: " + email);
        System.out.println("Office Phone: " + officePhone);
        System.out.println("Position: " + position);
    }
}

class InstitutionalCustomer implements Customer {
    private String id;
    private String name;
    private ContactPerson contactPerson;

    public InstitutionalCustomer(String id, String name, ContactPerson contactPerson) {
        this.id = id;
        this.name = name;
        this.contactPerson = contactPerson;
    }

    public void showInfo() {
        System.out.println("ID: " + id);
        System.out.println("Name: " + name);
        System.out.println("Contact Person: ");
        contactPerson.showInfo();
    }
}

class CustomerInformationSystem {
    private ArrayList<Customer> customers;

    public CustomerInformationSystem() {
        customers = new ArrayList<>();
    }

    public void addCustomer() {
        Scanner scanner = new Scanner(System.in);
        System.out.println("Add a customer:");
        System.out.println("Enter type (Individual or Institutional):");
        String type = scanner.nextLine();
        System.out.println("Enter ID:");
        String id = scanner.nextLine();
        System.out.println("Enter name:");
        String name = scanner.nextLine();
        if (type.equalsIgnoreCase("Individual")) {
            System.out.println("Enter phone:");
            String phone = scanner.nextLine();
            System.out.println("Enter email:");
            String email = scanner.nextLine();
            IndividualCustomer customer = new IndividualCustomer(id, name, phone, email);
            customers.add(customer);
        } else if (type.equalsIgnoreCase("Institutional")) {
            System.out.println("Enter contact person name:");
            String contactPersonName = scanner.nextLine();
            System.out.println("Enter contact person phone:");
            String contactPersonPhone = scanner.nextLine();
            System.out.println("Enter contact person email:");
            String contactPersonEmail = scanner.nextLine();
            System.out.println("Enter contact person office phone:");
            String contactPersonOfficePhone = scanner.nextLine();
            System.out.println("Enter contact person position:");
            String contactPersonPosition = scanner.nextLine();
            ContactPerson contactPerson = new ContactPerson(contactPersonName, contactPersonPhone, contactPersonEmail, contactPersonOfficePhone, contactPersonPosition);
            InstitutionalCustomer customer = new InstitutionalCustomer(id, name, contactPerson);
            customers.add(customer);
        } else {
            System.out.println("Invalid type.");
        }
    }

    public void printCustomers() {
        System.out.println("All customers:");
        for (Customer customer : customers) {
            customer.showInfo();
            System.out.println();
        }
    }
}

public class Main {
    public static void main(String[] args) {
        CustomerInformationSystem system = new CustomerInformationSystem();
        system.addCustomer();
        system.addCustomer();
        system.printCustomers();
    }
}

运行程序后，会提示输入客户信息，输入完毕后可以查看所有客户的信息。