需求:
为学生管理系统书写一个登陆、注册、忘记密码的功能只有用户登录成功之后，才能进入到学生管理系统中进行增删改查操作.
分析：
登录界面:
system.out.printIn("欢迎来到学生管理系统”) ;System.out.println("请选择操作1登录 2注册 3忘记密码");
用户类：
属性:用户名、密码、身份证号码、手机号码注册功能:
1，用户名需要满足以下要求:验证要求:
用户名唯一
用户名长度必须在3~15位之间
只能是字母加数字的组合，但是不能是纯数字2，密码键盘输入两次，两次一致才可以进行注册
3，身份证号码需要验证。
验证要求:
长度为18位
不能以0为开头
前17位，必须都是数字最为一位可以是数字，也可以是大写X或小写x
4，手机号验证。
验证要求
长度为11位
不能以0为开头
必须都是数字登录功能:
1，键盘录入用户名
2，键盘录入密码
3，键盘录入验证码
验证要求:
用户名如果未注册，直接结束方法，并提示:用户名未注册，请先注册判断验证码是否正确，如不正确，重新输入再判断用户名和密码是否正确，有3次机会忘记密码:
键盘录入用户名，判断当前用户名是否存在，如不存在，直接结束方法，并提示:未注册1.
键盘录入身份证号码和手机号码2
3，判断当前用户的身份证号码和手机号码是否一致
如果一致，则提示输入密码，进行修改
如果不一致，则提示: 账号信息不匹配，修改失败验证码规则:
长度为5
由4位大写或者小写字母和1位数字组成，同一个字母可重复
数字可以出现在任意位置
比如:
aQa1K
代码实现：
public class 学生管理系统_02 {
public static void main(String[] args) {
ArrayList<User> users = new ArrayList<>();
Scanner scanner = new Scanner(System.in);
while (true) {
System.out.println("--------欢迎来到Boss学生管理系统--------");
System.out.println("请选择操作：1.登录 2.注册 3.忘记密码");
String choose = scanner.next();
switch (choose) {
case "1":
System.out.println("请输入你的用户名：");
String uName = scanner.next();
User user1 = login(users, uName);
System.out.println(user1);
if (user1 != null) {
for (int i = 0; i < 3; i++) {
System.out.println("请输入你的密码：");
String uPassword = scanner.next();
String s = YanZheng();
System.out.println("请输入你的验证码：" + s);
String uYanZheng = scanner.next();
String password = user1.getPassword();
if (uYanZheng.equals(s) && password.equals(uPassword)) {
System.out.println("登录成功！");
indexMenu();
break;
} else {
System.out.println("密码或验证码错误！请重新输入！你还有" + (2 - i));
}
}
}
break;
case "2":
String username = null;
String password = null;
String idCard = null;
String pNumber = null;
//用户名
while (true) {
System.out.println("请输入你的用户名：");
username = scanner.next();
boolean flag = contains(users, username);
if (flag) {
if (username.length() >= 3 && username.length() <= 15) {
int count = 0;
for (int i = 0; i < username.length(); i++) {
//判断username中数字的个数
char c = username.charAt(i);
if (c >= '0' && c <= '9') {
count++;
}
}
if (count == 0 || count == username.length()) {
System.out.println("密码只能是字母加数字的组合！");
} else {
break;
}
} else {
System.out.println("密码长度要在3-15！");
}
} else {
System.out.println("用户名重复，请重新输入！！");
}
}
//密码
while (true) {
System.out.println("请输入密码：");
password = scanner.next();
System.out.println("请确认密码：");
String password1 = scanner.next();
if (!(password1.equals(password))) {
System.out.println("两次密码不一致，请重新输入");
} else {
break;
}
}
//身份证验证
while (true) {
System.out.println("请输入你的身份证：");
idCard = scanner.next();
char[] chars = idCard.toCharArray();
int length = chars.length;
if (length == 18 && chars[0] != '0' && (chars[length - 1] == 'X' || chars[length - 1] == 'x' || (chars[length - 1] >= '0' && chars[length - 1] <= '9'))) {
boolean mark = true;
for (int i = 0; i < chars.length - 1; i++) {
if (chars[i] >= '0' && chars[i] <= '9') {
} else {
System.out.println("身份证输入错误！");
mark = false;
break;
}
}
if (mark) {
break;
}
} else {
System.out.println("身份证输入有误，请重新输入！！！");
}
}
//手机号验证
while (true) {
System.out.println("请输入你的手机号码：");
pNumber = scanner.next();
if (pNumber.charAt(0) != '0' && pNumber.length() == 11) {
boolean mark = true;
for (int i = 0; i < pNumber.length(); i++) {
char c = pNumber.charAt(i);
if (c >= '0' && c <= '9') {
} else {
System.out.println("手机号码输入错误！");
mark = false;
break;
}
}
if (mark) {
break;
}
} else {
System.out.println("手机号码输入错误！");
}
}
User user = new User(username, password, idCard, pNumber);
users.add(user);
System.out.println("注册成功！");
break;
case "3":
System.out.println("请输入你要修改的用户名：");
String uname = scanner.next();
User user2 = login(users, uname);
if (user2 != null) {
System.out.println("请输入你的身份证号：");
String uId = scanner.next();
System.out.println("请输入你的手机号：");
String phoneNumber = scanner.next();
if (user2.getIdCard().equals(uId) && user2.getPNumber().equals(phoneNumber)) {
System.out.println("新密码：");
String newPassword = scanner.next();
user2.setPassword(newPassword);
System.out.println("修改成功！");
} else {
System.out.println("账号信息不匹配，修改失败！");
}
}
break;
default:
System.out.println("请输入正确的选项！！！！！！");
}
}
}
//校验用户名唯一
public static boolean contains(ArrayList<User> users, String username) {
for (int i = 0; i < users.size(); i++) {
User user = users.get(i);
if (user.getUsername().equals(username)) {
return false;
}
}
return true;
}
//随机产生一个验证码
public static String YanZheng() {
//将52个大写和小写字母添加到char数组中
char[] arr = new char[52];
for (int i = 0; i < arr.length; i++) {
if (i < 26) {
arr[i] = (char) (i + 65);
} else {
arr[i] = (char) (i + 97 - 26);
}
}
//随机取出数组中的4个数作为验证码的前4位
Random random = new Random();
char[] newArr = new char[5];
for (int i = 0; i < 4; i++) {
int radomIndex = random.nextInt(52);
newArr[i] = arr[radomIndex];
}
//产生随机的0-9的数字
int radomNumber = random.nextInt(10);
newArr[4] = (char) (radomNumber + 48);
//产生随机的索引 1-4
int radomIndex = random.nextInt(4);
char temp = newArr[radomIndex];
newArr[radomIndex] = newArr[4];
newArr[4] = temp;
return new String(newArr);
}
//验证登录
public static User login(ArrayList<User> users, String uName) {
boolean flag = contains(users, uName);
User user = null;
if (flag) {
System.out.println("用户未注册，请先注册！");
} else {
for (int i = 0; i < users.size(); i++) {
User user1 = users.get(i);
if (user1.getUsername().equals(uName)) {
user = user1;
}
}
}
return user;
}
public static void indexMenu() {
ArrayList<Student> students = new ArrayList<>();
Scanner scanner = new Scanner(System.in);
loop:
while (true) {
System.out.println("--------欢迎来到Boss学生管理系统--------");
System.out.println("1.添加学生");
System.out.println("2.删除学生");
System.out.println("3.修改学生");
System.out.println("4.查询学生");
System.out.println("5.查询所有学生");
System.out.println("6.退出");
System.out.println("请输入你的选择：");
String s = scanner.next();
switch (s) {
case "1":
System.out.println("请输入学生的id：");
Integer id = scanner.nextInt();
for (int i = 0; i < students.size(); i++) {
Student student = students.get(i);
if (student.getId().equals(id)) {
System.out.println("id重复，请重新输入！");
break loop;
}
}
System.out.println("请输入学生的name：");
String name = scanner.next();
System.out.println("请输入学生的age：");
int age = scanner.nextInt();
System.out.println("请输入学生的address：");
String address = scanner.next();
Student stu = new Student(id, name, age, address);
students.add(stu);
System.out.println("添加学生成功！");
break;
case "2":
System.out.println("请输入你要删除学生的id：");
Integer sid = scanner.nextInt();
boolean flag = delectStu(students, sid);
if (!flag) {
System.out.println("id不存在，请重新输入！");
}
break;
case "3":
System.out.println("请输入你要修改学生的id：");
Integer sid1 = scanner.nextInt();
boolean flag1 = updateStu(students, sid1, scanner);
if (!flag1) {
System.out.println("id不存在，请重新输入！");
}
break;
case "4":
System.out.println("请输入你要查询学生的id：");
Integer sid2 = scanner.nextInt();
boolean flag2 = selectStu(students, sid2);
if (!flag2) {
System.out.println("当前无学生信息，请添加后再次查询！");
}
break;
case "5":
if (students.size() != 0) {
selectStuAll(students);
} else {
System.out.println("当前学生信息为空，请进行添加！");
}
break;
case "6":
// System.exit(0);
break loop;
}
}
}
public static boolean delectStu(ArrayList<Student> students, Integer sid) {
for (int i = 0; i < students.size(); i++) {
Student student = students.get(i);
if (student.getId().equals(sid)) {
students.remove(i);
System.out.println("删除成功！");
return true;
}
}
return false;
}
public static boolean updateStu(ArrayList<Student> students, Integer sid, Scanner scanner) {
for (int i = 0; i < students.size(); i++) {
Student student = students.get(i);
if (student.getId().equals(sid)) {
System.out.println("请输入你要修改学生的name：");
String name1 = scanner.next();
System.out.println("请输入你要修改学生的age：");
int age1 = scanner.nextInt();
System.out.println("请输入你要修改学生的address：");
String address1 = scanner.next();
student.setName(name1);
student.setAge(age1);
student.setAddress(address1);
students.set(i, student);
System.out.println("修改成功！");
return true;
}
}
return false;
}
public static boolean selectStu(ArrayList<Student> students, Integer sid) {
for (int i = 0; i < students.size(); i++) {
Student student = students.get(i);
if (student.getId().equals(sid)) {
System.out.println("id=" + student.getId() + " name=" + student.getName() + " age=" + student.getAge() + " address=" + student.getAddress());
return true;
}
}
return false;
}
public static void selectStuAll(ArrayList<Student> students) {
for (int i = 0; i < students.size(); i++) {
Student student = students.get(i);
System.out.println("id=" + student.getId() + " name=" + student.getName() + " age=" + student.getAge() + " address=" + student.getAddress());
}
}
}