Java每日练习：客户信息管理

能够模拟实现基于文本界面的《客户信息管理软件》。该软件能够实现对客户对象的插入、修改和删除（用数组实现），并能够打印客户明细表。项目采用分级菜单方式。主菜单如下：

1.  每个客户的信息被保存在Customer对象中。
2. 以一个Customer类型的数组来记录当前所有的客户。
3. 每次“添加客户”（菜单1）后，客户（Customer）对象被添加到数组中。
4. 每次“修改客户”（菜单2）后，修改后的客户（Customer）对象替换数组中原对象。
5. 每次“删除客户”（菜单3）后，客户（Customer）对象被从数组中清除。
6. 执行“客户列表 ”（菜单4）时，将列出数组中所有客户的信息。 

本次项目基于MVC设计模式，将整个程序分为4层：bean层、service层、ui层以及util层，CustomerView为主模块，负责菜单的显示和处理用户操作；CustomerList为Customer对象的管理模块，内部用数组管理一组Customer对象，并提供相应的添加、修改、删除和遍历方法，供CustomerView调用；Customer为实体对象，用来封装客户信息，CMUtility为工具包可用来方便地实现键盘访问；结构如下图所示：

Customer类为实体类，用来封装客户的信息，该类封装客户的以下信息：

1. String name ：客户姓名
2. char gender  ：性别
3. int age          ：年龄
4. String phone：电话号码
5. String email ：电子邮箱

并给这些属性 提供各自属性的get/set方法以及提供所需的构造器（可自行确定）。

Custommer类

package bean;


public class Customer {
    //客户姓名
    private String name;
    //性别
    private char gender;
    //年龄
    private int age;
    //电话号码
    private String phone;
    //电子邮箱
    private String email;

    public String getName() {
        return name;
    }

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

    public char getGender() {
        return gender;
    }

    public void setGender(char gender) {
        this.gender = gender;
    }

    public int getAge() {
        return age;
    }

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

    public String getPhone() {
        return phone;
    }

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

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public Customer() {
    }

    public Customer(String name, char gender, int age, String phone, String email) {
        this.name = name;
        this.gender = gender;
        this.age = age;
        this.phone = phone;
        this.email = email;
    }
}

CustomerList为Customer对象的管理模块，内部使用数组管理一组Customer对象，用来保存客户对象的数组以及记录已保存客户对象的数量。

CustomerList类

package service;

import bean.Customer;


public class CustomerList {
    private Customer[] customers;//用来保存客户对象的数组
    private int total = 0;//记录已保存客户对象的数量


    
    public CustomerList(int totalCustomer) {
        customers = new Customer[totalCustomer];
    }

    
    public boolean addCustomer(Customer customer) {
        if (total >= customers.length) {
            return false;
        }
        customers[total++] = customer;
        return true;
    }

    
    public boolean replaceCustomer(int index, Customer customer) {
        if (index < 0 || index >= total) {
            return false;
        }
        customers[index] = customer;
        return true;
    }

    
    public boolean deleteCustomer(int index) {
        if (index < 0 || index >= total) {
            return false;
        }
        for (int i = index; i < total - 1; i++) {
            customers[i] = customers[i + 1];
        }
        customers[total - 1] = null;
        total--;
        return true;
    }

    
    public Customer[] getAllCustomers() {
        Customer[] customers1 = new Customer[total];
        for (int i = 0; i < total; i++) {
            customers1[i]=customers[i];
        }
        return customers1;
    }
    

    public Customer getCustomer(int index) {
        if (index < 0 || index >= total) {
            return null;
        }
        return customers[index];
    }
    
    public int getTotal() {
        return total;

    }


}

CustomerView为主模块，负责菜单的显示和处理用户操作；本类封装以下信息：CustomerList customerList = new CustomerList(10);创建最大包含10个客户对象的CustomerList 对象，供各成员方法使用。

CustomerView类

package ui;

import bean.Customer;
import service.CustomerList;
import util.CMUtility;


public class CustomerView {
    private CustomerList customerList = new CustomerList(10);
    
    public void enterMainMenu() {
        boolean isFlag = true;
        while (isFlag) {
            System.out.println("n-----------------客户信息管理软件-----------------n");
            System.out.println("                   1 添 加 客 户");
            System.out.println("                   2 修 改 客 户");
            System.out.println("                   3 删 除 客 户");
            System.out.println("                   4 客 户 列 表");
            System.out.println("                   5 退       出n");
            System.out.print("                   请选择(1-5)：");
            char menu = CMUtility.readMenuSelection();
            switch (menu) {
                case '1':
                    addNewCustomer();
                    break;
                case '2':
                    modifyCustomer();
                    break;
                case '3':
                    deleteCustomer();
                    break;
                case '4':
                    listAllCustomers();
                    break;
                case '5':
                    System.out.println("确认是否退出(Y/N):");
                    char isExit = CMUtility.readConfirmSelection();
                    if (isExit == 'Y') {
                        isFlag = false;
                    }
            }
        }
    }

    
    private void addNewCustomer() {
        System.out.println("---------------------添加客户---------------------");
        System.out.print("姓名：");
        String name = CMUtility.readString(4);
        System.out.print("性别：");
        char gender = CMUtility.readChar();
        System.out.print("年龄：");
        int age = CMUtility.readInt();
        System.out.print("电话：");
        String phone = CMUtility.readString(15);
        System.out.print("邮箱：");
        String email = CMUtility.readString(15);
        //将上述数据封装到对象中
        Customer customer=new Customer(name,gender,age,phone,email);
        boolean isSuccess=customerList.addCustomer(customer);
        if (isSuccess){
            System.out.println("---------------------添加完成---------------------");
        }else {
            System.out.println("----------------记录已满,无法添加-----------------");
        }
    }
    
    private void modifyCustomer() {
        System.out.println("---------------------修改客户---------------------");
        Customer customer;
        int number;
        for (; ; ) {
            System.out.print("请选择待修改客户编号(-1退出)：");
            number = CMUtility.readInt();
            if (number == -1) {
                return;
            }
            customer = customerList.getCustomer(number - 1);
            if (customer == null) {
                System.out.println("无法找到指定的客户！");
            } else {
                break;
            }
        }
        //修改客户信息
        System.out.print("姓名(" + customer.getName() + ")：");
        String name = CMUtility.readString(4, customer.getName());

        System.out.print("性别(" + customer.getGender() + ")：");
        char gender = CMUtility.readChar(customer.getGender());

        System.out.print("年龄(" + customer.getAge() + ")：");
        int age = CMUtility.readInt(customer.getAge());

        System.out.print("电话(" + customer.getPhone() + ")：");
        String phone = CMUtility.readString(15, customer.getPhone());

        System.out.print("邮箱(" + customer.getEmail() + ")：");
        String email = CMUtility.readString(15, customer.getEmail());
        Customer customer1 = new Customer(name, gender, age, phone, email);
        boolean isReplaced = customerList.replaceCustomer(number - 1, customer1);
        if (isReplaced) {
            System.out.println("---------------------修改完成---------------------");
        } else {
            System.out.println("---------------------修改失败---------------------");
        }
    }
    
    private void deleteCustomer() {
        System.out.println("---------------------删除客户---------------------");
        Customer customer;
        int number;
        for (; ; ) {
            System.out.print("请选择待删除客户编号(-1退出)：");
            number = CMUtility.readInt();
            if (number == -1) {
                return;
            }
            customer = customerList.getCustomer(number - 1);
            if (customer == null) {
                System.out.println("无法找到指定的客户！");
            } else {
                break;
            }
        }
        System.out.print("确认是否删除(Y/N)：");
        char isDelete = CMUtility.readConfirmSelection();
        if (isDelete == 'Y') {
            boolean deleteSuccess = customerList.deleteCustomer(number - 1);
            if (deleteSuccess) {
                System.out.println("---------------------删除完成---------------------");
            } else {
                System.out.println("---------------------删除失败---------------------");
            }
        }
    }

    
    private void listAllCustomers() {
        System.out.println("---------------------------客户列表---------------------------");
        int total = customerList.getTotal();
        if (total <= 0) {
            System.out.println("没有客户记录");
        } else {
            System.out.println("编号t姓名t性别t年龄t电话tt邮箱");
            Customer[] customers = customerList.getAllCustomers();
            for (int i = 0; i < total; i++) {
                Customer cust = customers[i];
                System.out.println((i + 1) + "t" + cust.getName() + "t" + cust.getGender() + "t" + cust.getAge()
                        + "t" + cust.getPhone() + "t" + cust.getEmail());
            }
        }
        System.out.println("-------------------------客户列表完成-------------------------");

    }

    public static void main(String[] args) {
        CustomerView view = new CustomerView();
        view.enterMainMenu();
    }

}

项目中提供了CMUtility.java类，可用来方便地实现键盘访问。该类提供了以下静态方法：

1. public static char readMenuSelection();用途：该方法读取键盘，如果用户键入’1’-’5’中的任意字符，则方法返回。返回值为用户键入字符。
2. public static char readChar() 和 public static char readChar(char defaultValue)用途：这两个方法功能相同，均从键盘读取一个字符，并将其作为方法的返回值。参数： defaultValue — 如果用户不输入字符而直接回车，方法将以defaultValue 作为返回值。（提示：此方法可在修改客户时调用）

CMUtility类

package util;

import java.util.Scanner;


public class CMUtility {
    private static Scanner scanner = new Scanner(System.in);

    
    public static char readMenuSelection() {
        char c;
        for (; ; ) {
            String str = readKeyBoard(1, false);
            c = str.charAt(0);
            if (c != '1' && c != '2' &&
                    c != '3' && c != '4' && c != '5') {
                System.out.print("选择错误，请重新输入：");
            } else break;
        }
        return c;
    }

    
    public static char readChar() {
        String str = readKeyBoard(1, false);
        return str.charAt(0);
    }

    
    public static char readChar(char defaultValue) {
        String str = readKeyBoard(1, true);
        return (str.length() == 0) ? defaultValue : str.charAt(0);
    }

    
    public static int readInt() {
        int n;
        for (; ; ) {
            String str = readKeyBoard(2, false);
            try {
                n = Integer.parseInt(str);
                break;
            } catch (NumberFormatException e) {
                System.out.print("数字输入错误，请重新输入：");
            }
        }
        return n;
    }

    
    public static int readInt(int defaultValue) {
        int n;
        for (; ; ) {
            String str = readKeyBoard(2, true);
            if (str.equals("")) {
                return defaultValue;
            }

            try {
                n = Integer.parseInt(str);
                break;
            } catch (NumberFormatException e) {
                System.out.print("数字输入错误，请重新输入：");
            }
        }
        return n;
    }

    
    public static String readString(int limit) {
        return readKeyBoard(limit, false);
    }

    
    public static String readString(int limit, String defaultValue) {
        String str = readKeyBoard(limit, true);
        return str.equals("") ? defaultValue : str;
    }

    
    public static char readConfirmSelection() {
        char c;
        for (; ; ) {
            String str = readKeyBoard(1, false).toUpperCase();
            c = str.charAt(0);
            if (c == 'Y' || c == 'N') {
                break;
            } else {
                System.out.print("选择错误，请重新输入：");
            }
        }
        return c;
    }

    private static String readKeyBoard(int limit, boolean blankReturn) {
        String line = "";

        while (scanner.hasNextLine()) {
            line = scanner.nextLine();
            if (line.length() == 0) {
                if (blankReturn) return line;
                else continue;
            }

            if (line.length() < 1 || line.length() > limit) {
                System.out.print("输入长度（不大于" + limit + "）错误，请重新输入：");
                continue;
            }
            break;
        }

        return line;
    }
}