需求描述
实现简单的登录注册功能，要求以下几点：
1.注册时对两次输入的密码进行验证
2.检查注册的用户名是否已经存在
代码实现
代码结构图：
package cn.test.logan.day07.login; import java.util.Scanner; import cn.test.logan.day07.login.service.UserService; import cn.test.logan.day07.login.service.UserServiceImpl; /** * 用户登录认证，主要实现以下功能： * 1.根据选择的菜单选项【1.登录 2.注册 quit.退出】，进行操作 * 2.当用户选择登录，先验证用户是否存在，如果存在，则验证密码是否正确，如果用户不存在或者密码错误，统一返回"Sorry,用户名或密码错误" * 3.实现注册 * - 用户输入两次密码，验证两次密码是否一致 * - 查询注册账号是否存在，存在则提示 * @author QIN * */ public class UserLogin { public static void main(String[] args) { Scanner sc = new Scanner(System.in); // 引用接口类型变量 // UserService service = null; UserService service = new UserServiceImpl(); boolean flag = true; while(flag) { System.out.println("1.登录; 2.注册; quit.退出"); String line = sc.nextLine(); switch(line) { case "1": System.out.println("请输入您的用户名："); String username = sc.nextLine(); System.out.println("请输入您的密码："); String password = sc.nextLine(); // 调用登录方法进行登录 boolean status = service.login(username, password); if(status) { System.out.println("您已经登录成功！"); }else { System.out.println("Sorry,用户名或密码错误！"); } break; case "2": System.out.println("请输入你的用户名:"); String uname = sc.nextLine(); System.out.println("请输入你的密码："); String pwd1 = sc.nextLine(); System.out.println("请确认你的密码："); String pwd2 = sc.nextLine(); String res = service.regist(uname, pwd1, pwd2); switch(res) { case "1": System.out.println("你两次输入的密码不一致."); break; case "2": System.out.println("你要注册的账号已经存在."); break; case "3": System.out.println("你已经注册成功了！恭喜你."); break; default: break; } break; case "quit": System.out.println("程序已退出..........."); flag = false; break; } } } }
package cn.test.logan.day07.login; import java.util.HashMap; import cn.test.logan.day07.login.pojo.User; public class UserDatabase { public static HashMap<String,User> userMap = new HashMap<>(); /** * 定义静态代码块，在类被jvm加载时，静态代码就行执行 */ static { User u1 = new User(); u1.set("admin","1"); User u2 = new User(); u2.set("Logan","1"); userMap.put(u1.getUsername(), u1); userMap.put(u2.getUsername(), u2); } }
service层
package cn.test.logan.day07.login.service; /** * 定义两个方法：login、regist * @author QIN * */ public interface UserService { // 登录方法 public boolean login(String username,String pwd); // 注册方法 public String regist(String username,String pwd1,String pwd2); }
package cn.test.logan.day07.login.service; import cn.test.logan.day07.login.dao.UserDao; import cn.test.logan.day07.login.dao.UserDaoImpl; import cn.test.logan.day07.login.pojo.User; public class UserServiceImpl implements UserService{ // UserDao userdao = null; UserDao userdao = new UserDaoImpl(); @Override public boolean login(String username, String pwd) { //调用DAO层，根据用户名查询返回一个用户对象 User user = userdao.selectUser(username); if(user==null) { return false; } if(user.getPassword().equals(pwd)) { return true; } return false; } @Override public String regist(String username, String pwd1, String pwd2) { // 检查密码是否一致 if(!pwd1.equals(pwd2)) { return "1"; } // 检查用户已经存在则返回2 boolean res = userdao.checkUser(username); if(res) { return "2"; } // User u = new User(); u.set(username, pwd1); userdao.addUser(u); return "3"; } }
dao层
package cn.test.logan.day07.login.dao; import cn.test.logan.day07.login.pojo.User; public interface UserDao { public User selectUser(String username); public boolean checkUser(String username); public void addUser(User user); }
package cn.test.logan.day07.login.dao; import cn.test.logan.day07.login.UserDatabase; import cn.test.logan.day07.login.pojo.User; public class UserDaoImpl implements UserDao{ /** * 根据一个用户名到数据库中查找该用户 */ @Override public User selectUser(String username) { User user = UserDatabase.userMap.get(username); return user; } /** * 检查数据库中是否已存在该用户 */ @Override public boolean checkUser(String username) { boolean containsKey = UserDatabase.userMap.containsKey(username); return containsKey; } /** * 将传入的user对象存入数据库 */ @Override public void addUser(User user) { UserDatabase.userMap.put(user.getUsername(), user); } }
pojo层
package cn.test.logan.day07.login.pojo; public class User { private String username; private String password; public void set(String username,String password) { this.username = username; this.password = password; } // 生成get与set 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; } }