目标 熟悉面向对象编程
涉及的知识 ：
类结构的使用：属性、方法和构造器
对象的创建与使用
类的封装性
声明和使用数组
数组的插入、删除、替换、增加
关键字使用：this
工具类Utility的定义
将不同的功能封装为方法，就是可以直接通过调用方法使用它的功能，而无需考虑具体的功能实现细节。
首先创建Scanner类以供后续本类使用。循环获取控制台输入的字符串并存入字符串line中，判断字符串line是否为0、为负或超出限制都将重新获取line。
成功获取则返回line。
1 private static Scanner scanner = new Scanner(System.in);
2
3 private static String readKeyBoard(int limit, boolean blankReturn) {
4 String line = "";
5
6 while (scanner.hasNextLine()) {
7 line = scanner.nextLine();
8 if (line.length() == 0) {
9 if (blankReturn) return line;
10 else continue;
11 }
12
13 if (line.length() < 1 || line.length() > limit) {
14 System.out.print("输入长度（不大于" + limit + "）错误，请重新输入：");
15 continue;
16 }
17 break;
18 }
19
20 return line;
用于界面菜单的选择。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。
1 public static char readMenuSelection() {
2 char c;
3 for (; ; ) {
4 String str = readKeyBoard(1, false);
5 c = str.charAt(0);
6 if (c != '1' && c != '2' &&
7 c != '3' && c != '4' && c != '5') {
8 System.out.print("选择错误，请重新输入：");
9 } else break;
10 }
11 return c;
12 }
从键盘读取一个字符，并将其作为方法的返回值。
如果用户不输入字符而直接回车，方法将以defaultValue 作为返回值。
1 public static char readChar() {
2 String str = readKeyBoard(1, false);
3 return str.charAt(0);
4 }
5
6 //重载 修改用户信息时使用
7 public static char readChar(char defaultValue) {
8 String str = readKeyBoard(1, true);
9 return (str.length() == 0) ? defaultValue : str.charAt(0);
10 }
从键盘读取一个长度不超过2位的整数，并将其作为方法的返回值。
如果用户不输入字符而直接回车，方法将以defaultValue 作为返回值。
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;
}
//重载 修改用户信息时使用
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;
}
从键盘读取一个长度不超过limit的字符串，并将其作为方法的返回值。
如果用户不输入字符而直接回车，方法将以defaultValue 作为返回值。
public static String readString(int limit) {
return readKeyBoard(limit, false);
}
//重载 同上
public static String readString(int limit, String defaultValue) {
String str = readKeyBoard(limit, true);
return str.equals("")? defaultValue : str;
}
用于确认选择的输入。该方法从键盘读取‘Y’或’N’，并将其作为方法的返回值。
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;
}
用户类Customer的定义
public class Customer {
private String name;
private char gender;
private int age;
private String phone;
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;
}
//实例化用户对象时赋值
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;
}
//空参构造器
public Customer(){
}
//用户各个属性的值作为字符串返回
public String getDetails(){
return getName() + "\t" + getGender() + "\t" + getAge() + "\t\t" + getPhone() + "\t" +getEmail();
}
使用数组管理Customer类对象的CustomerList的定义
定义两个成员变量，以及一个带参构造器。
private Customer[] customers; //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() {
}
public CustomerList(int totalCustomer) {
customers = new Customer[totalCustomer];
}
实现数组对象的增删改，操作成功返回true，失败则返回false
//增
public boolean addCustomer(Customer customer){
if (customers.length < total)
return false;
customers[total] = customer;
total++;
return true;
}
//删
public boolean deleteCustomer(int index){
if (index >= 0 && index < total)
{
for (int i = index; i < total - 1; i++) {
customers[i] = customers[i+1];
}
customers[total -1] = null;
total--;
return true;
}
return false;
}
//改
public boolean replaceCustomer(int index,Customer cust){
if (index >= 0 && index < total)
{
customers[index] = cust;
return true;
}
return false;
}
实现数组对象的查询，操作成功返回true，失败则返回false
//查询所有用户信息
public Customer[] getAllCustomers(){
Customer[] a = new Customer[total];
for (int i = 0; i < total; i++) {
a[i] = customers[i];
}
return a;
}
//查询具体索引编号的用户信息
public Customer getCustomer(int index){
if (index < 0 || index >= total){
return null;
}else
return customers[index];
}
用户界面类CustomerView的实现
设置数组长度，以及存入一组数据以供显示使用
//创建一个对象数组，并限定长度
private CustomerList customers = new CustomerList(10);
//将一组对象存入对象数组中
public CustomerView() {
Customer cust = new Customer("张三", '男', 30, "13843255423", "[email protected]");
customers.addCustomer(cust);
}
控制台显示界面的实现
//菜单界面
public void enterMainMenu(){
boolean isflag = true;
while (isflag){
System.out
.println("\n-------------------拼电商客户管理系统-----------------\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 key = CMUtility.readMenuSelection();
switch (key) {
case '1':
addNewCustomer();
break;
case '2':
modifyCustomer();
break;
case '3':
deleteCustomer();
break;
case '4':
listAllCustomers();
break;
case '5':
System.out.print("确认是否退出(Y/N)：");
char yn = CMUtility.readConfirmSelection();
if (yn == 'Y')
isflag = false;
break;
}
}
}
//增 界面
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);
Customer cust = new Customer(name, gender, age, phone, email);
boolean flag = customers.addCustomer(cust);
if (flag) {
System.out
.println("---------------------添加完成---------------------");
} else {
System.out.println("----------------记录已满,无法添加-----------------");
}
}
//改 界面
private void modifyCustomer(){
System.out.println("---------------------修改客户---------------------");
int index = 0;
Customer cust = null;
for (;;) {
System.out.print("请选择待修改客户编号(-1退出)：");
index = CMUtility.readInt();
if (index == -1) {
return;
}
cust = customers.getCustomer(index - 1);
if (cust == null) {
System.out.println("无法找到指定客户！");
} else
break;
}
System.out.print("姓名(" + cust.getName() + ")：");
String name = CMUtility.readString(4, cust.getName());
System.out.print("性别(" + cust.getGender() + ")：");
char gender = CMUtility.readChar(cust.getGender());
System.out.print("年龄(" + cust.getAge() + ")：");
int age = CMUtility.readInt(cust.getAge());
System.out.print("电话(" + cust.getPhone() + ")：");
String phone = CMUtility.readString(15, cust.getPhone());
System.out.print("邮箱(" + cust.getEmail() + ")：");
String email = CMUtility.readString(15, cust.getEmail());
cust = new Customer(name, gender, age, phone, email);
boolean flag = customers.replaceCustomer(index - 1, cust);
if (flag) {
System.out
.println("---------------------修改完成---------------------");
} else {
System.out.println("----------无法找到指定客户,修改失败--------------");
}
}
//删 界面
private void deleteCustomer(){
System.out.println("---------------------删除客户---------------------");
int index = 0;
Customer cust = null;
for (;;) {
System.out.print("请选择待删除客户编号(-1退出)：");
index = CMUtility.readInt();
if (index == -1) {
return;
}
cust = customers.getCustomer(index - 1);
if (cust == null) {
System.out.println("无法找到指定客户！");
} else
break;
}
System.out.print("确认是否删除(Y/N)：");
char yn = CMUtility.readConfirmSelection();
if (yn == 'N')
return;
boolean flag = customers.deleteCustomer(index - 1);
if (flag) {
System.out
.println("---------------------删除完成---------------------");
} else {
System.out.println("----------无法找到指定客户,删除失败--------------");
}
}
//查 界面
private void listAllCustomers(){
System.out.println("---------------------------客户列表---------------------------");
Customer[] custs = customers.getAllCustomers();
if (custs.length == 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\t\t\t邮箱");
for (int i = 0; i < custs.length; i++) {
// System.out.println(i + 1 + "\t" + custs[i].getName() + "\t" + custs[i].getGender() + "\t" + custs[i].getAge() + "\t\t" + custs[i].getPhone() + "\t" + custs[i].getEmail());
System.out.println((i+1) + "\t" + custs[i].getDetails());
}
}
System.out.println("-------------------------客户列表完成-------------------------");
}
main方法测试上述所有代码功能是否实现
public static void main(String[] args){
CustomerView cView = new CustomerView();
cView.enterMainMenu();
}
标签：return,String,管理系统,int,System,简易,控制台,public,out From： https://www.cnblogs.com/wt-0831/p/17671511.html