（自定义异常）完成某个计费系统的用户登录和注册模块

/**
 * @Author Liu Lei
 * @Date 2020/8/31 16:01
 * @Version 1.0
 * @description
 * 登陆异常
 */
public class IllegalLoginException extends Exception {
    public IllegalLoginException() {
    }

    public IllegalLoginException(String message) {
        super(message);
    }
}

/**
 * @Author Liu Lei
 * @Date 2020/8/31 16:02
 * @Version 1.0
 * @description
 * 注册异常
 */
public class IllegalRegisterException extends Exception {

    public IllegalRegisterException() {
    }

    public IllegalRegisterException(String message) {
        super(message);
    }
}

import java.util.Scanner;

/**
 * @Author Liu Lei
 * @Date 2020/8/31 17:13
 * @Version 1.0
 * @description
 */
public class TestUser {

    public static void main(String[] args){
        UserViewImpl uv = new UserViewImpl();
        do{
            Scanner sc = new Scanner(System.in);
            System.out.println("请选择执行的操作：
1、登陆
2、注册
3 退出");
            int i = sc.nextInt();
            if(i==1){
                uv.login();
            }
            else if(i==2){
                uv.register();
            }
            else {
                break;
            }
        }while(true);
    }
}

/**
 * @Author Liu Lei
 * @Date 2020/8/31 15:58
 * @Version 1.0
 * @description
 *创建一个User 类，包括：用户登录名（username）、密码（password）、用户真实姓
 * 名（name）、电子邮件地址（email）属性和相应的构造方法及setter/getter 方法。
 */
public class User {
    private String username ;
    private  String password ;
    private String name ;
    private  String email ;

    public User() {
    }


    public User(String username, String password, String name, String email) {
        this.username = username;
        this.password = password;
        this.name = name;
        this.email = email;
    }


    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;
    }

    public String getName() {
        return name;
    }

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

    public String getEmail() {
        return email;
    }

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

/**
 * @Author Liu Lei
 * @Date 2020/8/31 16:03
 * @Version 1.0
 * @description
 */
public interface UserBiz {

    void register(String username, String password, String rePassword,
                  String name, String email) throws IllegalRegisterException ;//用户注册
    void login(String username, String password) throws IllegalLoginException ;//用户登录

}

import java.util.Scanner;

/**
 * @Author Liu Lei
 * @Date 2020/8/31 16:05
 * @Version 1.0
 * @description
 */
public class UserBizImpl implements UserBiz {

    static int index=0;
    static Scanner sc = new Scanner(System.in);
    static User[] users=new User[10];
    static{
        users[0]=new User("admin", "admin", "Adminstrator", "admin@123.com");
        users[1]=new User("Tom", "cat", "tomcat", "tomcat@cat.com");
    }

    @Override
    public void register(String username, String password, String rePassword, String name, String email) throws IllegalRegisterException {
        if(!password.equals(rePassword)){
            throw new IllegalRegisterException("两次密码不一致");
        }
        for(int i = 0;i<users.length;i++){
            if(users[i] ==null){

                break;
            }
            if(users[i].getUsername().equals(username)){

                throw new IllegalRegisterException("用户名已经存在");
            }
        }
        users[index]=new User(username, rePassword, name, email);
        index++;
        System.out.println("注册成功");
    }

    @Override
    public void login(String username, String password) throws IllegalLoginException {
        boolean flag = false;
        for(int i=0;i<users.length;i++) {
            if (users[i] == null) {
                break;
            }
            if (users[i].getUsername().equals(username)) {
                if (!users[i].getPassword().equals(password)) {
                    throw new IllegalLoginException("用户名与密码不匹配");
                }
                if (users[i].getUsername().equals(username)) {
                    flag = true;
                }
            }
        }
        if(!flag) {
            throw new IllegalLoginException("用户名不存在");
        }
        System.out.println("登陆成功");
    }





    }

/**
 * @Author Liu Lei
 * @Date 2020/8/31 16:23
 * @Version 1.0
 * @description
 */
public interface UserView {

    void login() throws IllegalLoginException;
    void register();

}

import java.util.Scanner;

/**
 * @Author Liu Lei
 * @Date 2020/8/31 16:24
 * @Version 1.0
 * @description
 */
public class UserViewImpl implements UserView {
    static UserBiz ub =new UserBizImpl();
    static Scanner sc= new Scanner(System.in);

    @Override
    public void login()  {

        System.out.println("请输入用户名:");
        String username = sc.next();
        System.out.println("请输入密码:");
        String password = sc.next();
        try{

            ub.login(username,password);

        }catch (IllegalLoginException e){
            e.printStackTrace();
        }



    }

    @Override
    public void register() {
        Scanner sc = new Scanner(System.in);
        System.out.println("请输入用户名:");
        String username=sc.next();
        System.out.println("请输入密码:");
        String password=sc.next();
        System.out.println("请再次输入密码:");
        String password2 = sc.next();
        System.out.println("请输入姓名:");
        String name = sc.next();
        System.out.println("请输入邮箱地址");
        String email = sc.next();
        try {
            ub.register(username, password, password2, name, email);
        } catch (IllegalRegisterException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
            return ;
        }
    }
}