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Java collection realizes simple user registration and login and plays guessing number game demo
Java uses IO to realize simple user registration and login and plays guessing number game demo
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1. Project scenario
Simply use the Java collection to fully realize the case of user registration and login and play a small game of guessing numbers.
(Number guessing game: the system randomly generates a number between 1-100 for the user to guess, and gives prompts for guessing big, small, and the number of correct guesses)
2. Analysis
What classes are there?
– User class
– Test class
What does each class contain?
–User class:
–Member variable: username (username), password (password)
–Construction method: no parameter construction
–Member method: getXxx() / setXxx()
–Test class:
–main() method
What is the relationship between classes and classes?
– Create objects of user operation class and user basic description class in the test class, and use their functions.
Subpackage by function
– user basic description class package pojo
– user operation interface dao
– user operation class package dao.impl
– user test classtest
The project directory structure is shown in the figure
Three, realize
User basic description class User.java
package pojo;
public class User {
// 用户名
private String username;
// 密码
private String password;
public User() {
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
}
User operation interface UserDao.java
package dao;
import pojo.User;
/**
* 这是针对用户进行操作的接口
*
* @author Y
* @version V1.0
*
*/
public interface UserDao {
/**
* 这是用户登录功能
*
* @param username
* 用户名
* @param password
* 密码
* @return 返回登录是否成功
*/
public abstract boolean isLogin(String username, String password);
/**
*
* @param user
* 要注册的用户信息
*/
public void regist(User user);
}
The specific implementation of the user operation class UserDaoImpl.java
package dao.impl;
import dao.UserDao;
import pojo.User;
import java.util.ArrayList;
/**
* 这是用户操作的具体实现类
*
* @author Y
* @version V1.0
*/
public class UserDaoImpl implements UserDao {
// 为了让多个方法能够使用同一个集合，就把集合定义为成员变量
// 为了不让外人看到，用private
// 为了让多个对象共享同一个成员变量，用static
private static ArrayList<User> array = new ArrayList<User>();
@Override
public boolean isLogin(String username, String password) {
// 遍历集合，获取每一个用户，并判断该用户的用户名和密码是否和传递过来的匹配
boolean flag = false;
for (User u: array) {
if (u.getUsername().equals(username) && u.getPassword().equals(password)) {
flag = true;
break;
}
}
return flag;
}
@Override
public void regist(User user) {
array.add(user);
}
}
Guess the number game GuessNumber.java
package game;
import java.util.Scanner;
/**
* 猜数字小游戏
*
* @author Y
* @version V1.0
*
*/
public class GuessNumber {
private GuessNumber() {
}
public static void start() {
// 产生一个随机数
int number = (int) (Math.random() * 100) + 1;
// 定义一个统计变量
int count = 0;
while (true) {
// 键盘录入一个数据
Scanner sc = new Scanner(System.in);
System.out.println("请输入数据（1-100）：");
int guessNumber = sc.nextInt();
count++;
// 判断
if (guessNumber > number) {
System.out.println("你猜的数据" + guessNumber + "大了");
} else if (guessNumber < number) {
System.out.println("你猜的数据" + guessNumber + "小了");
} else {
System.out.println("恭喜你" + count + "次就猜中了");
break;
}
}
}
}
Implementation of user test class UserTest.java
import dao.UserDao;
import dao.impl.UserDaoImpl;
import game.GuessNumber;
import pojo.User;
import java.util.Scanner;
/**
* 用户测试类
*
* @author Y
* @version V1.0
*
*/
public class UserTest {
public static void main(String[] args) {
// 为了能够回到首界面
while (true) {
// 欢迎界面给出选择项
System.out.println("------------欢迎光临------------");
System.out.println("1登录");
System.out.println("2注册");
System.out.println("3退出");
System.out.println("请输入你的选择");
// 键盘录入选择，根据选择做不同的操作
Scanner sc = new Scanner(System.in);
String choiceString = sc.nextLine();
// switch语句的多个地方要使用，因此定义在外面
// 多态
UserDao ud = new UserDaoImpl();
switch (choiceString) {
case "1":
// 登录界面，输入用户名和密码
System.out.println("------------登录界面------------");
System.out.println("请输入用户名：");
String username = sc.nextLine();
System.out.println("请输入密码：");
String password = sc.nextLine();
// 调用登录功能
boolean flag = ud.isLogin(username, password);
if (flag) {
System.out.println("登录成功！");
System.out.println("你玩猜数字游戏吗？y/n");
while (true) {
String resultString = sc.nextLine();
if (resultString.equalsIgnoreCase("y")) {
// 玩猜数字游戏
GuessNumber.start();
System.out.println("你还玩吗？y/n");
} else {
break;
}
}
System.out.println("谢谢使用，欢迎下次再来！");
System.exit(0);
// 这里如果用break，结束的是switch
} else {
System.out.println("用户名或密码错误，登录失败");
}
break;
case "2":
// 欢迎界面，请输入用户名和密码
System.out.println("------------注册界面------------");
System.out.println("请输入用户名：");
String newUsername = sc.nextLine();
System.out.println("请输入密码：");
String newPassword = sc.nextLine();
// 把用户名和密码封装到一个对象中
User user = new User();
user.setUsername(newUsername);
user.setPassword(newPassword);
// 调用注册功能
// 具体类使用
ud.regist(user);
System.out.println("注册成功！");
break;
case "3":
default:
System.out.println("谢谢使用，欢迎下次再来！");
System.exit(0);
break;
}
}
}
}
4. Demonstration
Registered three users: Zhao Meng, Yu Wenwen, Liu Lian
User Zhao Meng logs in, chooses whether to play the number guessing game, chooses to play
the number guessing game
and ends
References:
Refer to Liu Yi's JavaSE video