详解Java如何使用集合来实现一个客户信息管理系统

1. 概述

在Java中，可以使用集合类来实现一个简单的客户信息管理系统。集合类提供了丰富的数据结构和操作方法，能够满足各种需求。

我们可以使用List或Set来存储客户信息，在程序中实现增删改查等操作。同时，我们可以利用Map来存储客户信息，实现键值对的存储，方便以后的查找和遍历。

2. 使用List实现一个客户信息管理系统

我们可以使用List来存储客户信息，同时利用Scanner类实现控制台输入，简单实现增删改查等操作。

在下面的示例代码中，我们定义一个Customer类，其中包含姓名和电话两个字段。接着，我们使用ArrayList来存储Customer对象，实现客户信息的管理。

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

public class CustomerManagementSystem {
    private List<Customer> customers = new ArrayList<>();

    public static void main(String[] args) {
        CustomerManagementSystem system = new CustomerManagementSystem();
        system.run();
    }

    private void run() {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            displayMenu();

            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    addCustomer(scanner);
                    break;
                case 2:
                    deleteCustomer(scanner);
                    break;
                case 3:
                    updateCustomer(scanner);
                    break;
                case 4:
                    queryCustomer(scanner);
                    break;
                case 5:
                    showCustomers();
                    break;
                case 6:
                    System.out.println("Goodbye!");
                    scanner.close();
                    System.exit(0);
                    break;
                default:
                    System.out.println("Invalid choice, please try again.");
                    break;
            }
        }
    }

    private void displayMenu() {
        System.out.println("-------- Customer Management System --------");
        System.out.println("1. Add customer");
        System.out.println("2. Delete customer");
        System.out.println("3. Update customer");
        System.out.println("4. Query customer");
        System.out.println("5. Show all customers");
        System.out.println("6. Exit");
        System.out.print("Please enter your choice: ");
    }

    private void addCustomer(Scanner scanner) {
        System.out.print("Please enter customer name: ");
        String name = scanner.next();

        System.out.print("Please enter customer phone: ");
        String phone = scanner.next();

        Customer customer = new Customer(name, phone);
        customers.add(customer);

        System.out.println("Add customer success!");
    }

    private void deleteCustomer(Scanner scanner) {
        System.out.print("Please enter customer name: ");
        String name = scanner.next();

        for (Iterator<Customer> iterator = customers.iterator(); iterator.hasNext();) {
            Customer customer = iterator.next();
            if (customer.getName().equals(name)) {
                iterator.remove();
                System.out.println("Delete customer success!");
                return;
            }
        }

        System.out.println("Customer not found!");
    }

    private void updateCustomer(Scanner scanner) {
        System.out.print("Please enter customer name: ");
        String name = scanner.next();

        for (Customer customer : customers) {
            if (customer.getName().equals(name)) {
                System.out.print("Please enter new customer phone: ");
                String phone = scanner.next();

                customer.setPhone(phone);
                System.out.println("Update customer success!");
                return;
            }
        }

        System.out.println("Customer not found!");
    }

    private void queryCustomer(Scanner scanner) {
        System.out.print("Please enter customer name: ");
        String name = scanner.next();

        for (Customer customer : customers) {
            if (customer.getName().equals(name)) {
                System.out.println(customer.toString());
                return;
            }
        }

        System.out.println("Customer not found!");
    }

    private void showCustomers() {
        for (Customer customer : customers) {
            System.out.println(customer.toString());
        }
    }
}

class Customer {
    private String name;
    private String phone;

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

    public String getName() {
        return name;
    }

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

    public String getPhone() {
        return phone;
    }

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

    @Override
    public String toString() {
        return String.format("Name: %s, Phone: %s", name, phone);
    }
}

在上述代码中，我们利用Scanner类获取控制台输入，并使用ArrayList来存储Customer对象。通过迭代器进行遍历，并实现增删改查等操作。

3. 使用Map实现一个客户信息管理系统

我们也可以使用Map来存储客户信息，同时实现键值对的存储，方便以后的查找和遍历。在下面的示例代码中，我们依旧定义一个Customer类，其中包含姓名和电话两个字段。接着，我们使用HashMap来存储Customer对象，并利用键值对存储客户信息。

import java.util.HashMap;
import java.util.Map;
import java.util.Scanner;

public class CustomerManagementSystem {
    private Map<String, Customer> customers = new HashMap<>();

    public static void main(String[] args) {
        CustomerManagementSystem system = new CustomerManagementSystem();
        system.run();
    }

    private void run() {
        Scanner scanner = new Scanner(System.in);
        while (true) {
            displayMenu();

            int choice = scanner.nextInt();
            switch (choice) {
                case 1:
                    addCustomer(scanner);
                    break;
                case 2:
                    deleteCustomer(scanner);
                    break;
                case 3:
                    updateCustomer(scanner);
                    break;
                case 4:
                    queryCustomer(scanner);
                    break;
                case 5:
                    showCustomers();
                    break;
                case 6:
                    System.out.println("Goodbye!");
                    scanner.close();
                    System.exit(0);
                    break;
                default:
                    System.out.println("Invalid choice, please try again.");
                    break;
            }
        }
    }

    private void displayMenu() {
        System.out.println("-------- Customer Management System --------");
        System.out.println("1. Add customer");
        System.out.println("2. Delete customer");
        System.out.println("3. Update customer");
        System.out.println("4. Query customer");
        System.out.println("5. Show all customers");
        System.out.println("6. Exit");
        System.out.print("Please enter your choice: ");
    }

    private void addCustomer(Scanner scanner) {
        System.out.print("Please enter customer name: ");
        String name = scanner.next();

        System.out.print("Please enter customer phone: ");
        String phone = scanner.next();

        Customer customer = new Customer(name, phone);
        customers.put(name, customer);

        System.out.println("Add customer success!");
    }

    private void deleteCustomer(Scanner scanner) {
        System.out.print("Please enter customer name: ");
        String name = scanner.next();

        if (customers.containsKey(name)) {
            customers.remove(name);
            System.out.println("Delete customer success!");
        } else {
            System.out.println("Customer not found!");
        }
    }

    private void updateCustomer(Scanner scanner) {
        System.out.print("Please enter customer name: ");
        String name = scanner.next();

        if (customers.containsKey(name)) {
            System.out.print("Please enter new customer phone: ");
            String phone = scanner.next();

            Customer customer = new Customer(name, phone);
            customers.put(name, customer);

            System.out.println("Update customer success!");
        } else {
            System.out.println("Customer not found!");
        }
    }

    private void queryCustomer(Scanner scanner) {
        System.out.print("Please enter customer name: ");
        String name = scanner.next();

        if (customers.containsKey(name)) {
            Customer customer = customers.get(name);
            System.out.println(customer.toString());
        } else {
            System.out.println("Customer not found!");
        }
    }

    private void showCustomers() {
        for (String name : customers.keySet()) {
            System.out.println(customers.get(name).toString());
        }
    }
}

class Customer {
    private String name;
    private String phone;

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

    public String getName() {
        return name;
    }

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

    public String getPhone() {
        return phone;
    }

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

    @Override
    public String toString() {
        return String.format("Name: %s, Phone: %s", name, phone);
    }
}

在上述代码中，我们使用HashMap来存储Customer对象，通过键值对实现客户信息的存储和查找。同样的，我们通过Scanner类获取控制台输入，并实现增删改查等操作。

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