使用另一种方法的对象实例

debugcn 发表于 Dev

吃你的猫

我最近才开始在我的大学的暑期课程中使用 Java 编码，所以我的代码知识和代码都低于标准。

这个作业要求我创建一个带有登录方法以及访问器和修改器的 User 类。一个具有动态大小的用户集合的 EmailSystem 类，一个将创建 User 对象并将其添加到用户列表的 registerUser 方法，以及一个将遍历用户列表的 listUser 方法。

EmailSystem 类的代码：

public class EmailSystem {
   public static ArrayList<User> userList = new ArrayList<>();

   public static void registerUser(String firstname, String lastname, String username, String password) {
      User myUser = new User(firstname, lastname, username, password);
      userList.add(myUser);
      }

   public static void listUsers () {
      for (int i=0; i<userList.size(); i++)
      {
         System.out.println(userList.get(i));
      }
   }

   public static void main(String[] args) {
      registerUser("John", "Doe", "Username", "Password");
   }
}

用户类代码

import javax.swing.JOptionPane;
import java.util.*;

public class EmailSystem {
   public static ArrayList<User> userList = new ArrayList<>();

   public static void registerUser(String firstname, String lastname, String username, String password) {
      User myUser = new User(firstname, lastname, username, password);
      userList.add(myUser);
      }


   public static void listUsers () {
      for (int i=0; i<userList.size(); i++)
      {
         System.out.println(userList.get(i));
      }
   }

   public static void main(String[] args) {
      registerUser("John", "Doe", "Username", "Password");
      boolean hasExit = false;
      while (hasExit == false)
      {
         String options = "";
         options = JOptionPane.showInputDialog("The following actions are supported. Enter the code: \nA: Login\nB: Print Users\nC: Exit");
         if (options.equalsIgnoreCase ("A"))
         {
            String username = JOptionPane.showInputDialog("Username");
            String password = JOptionPane.showInputDialog("Password");
            // I would like to check whether the username and password submitted here are the same as the one used to register  
            // Use userLogin method here to compare the username and password that is inputted here and the username and password that was created when registering.
         }
         else if (options.equalsIgnoreCase ("B"))  
         {
            listUsers();
         }      
         else if (options.equalsIgnoreCase ("C"))
         {
            hasExit = true;
         }
      }  

   }
}

注册用户时，如何在创建的对象上运行 userLogin 方法？还是我应该完全做其他事情？

死池

对于 registerUser 方法，将返回类型更改为 User

 public static User registerUser(String firstname, String lastname, String 
  username, String password) {
      User myUser = new User(firstname, lastname, username, password);
      userList.add(myUser);
      return myUser;
      }

对于用户名和密码的验证，您检查以下逻辑，或者您可以在 userValidate 方法中编写以下逻辑并在 options = "A" 时调用该方法

public static void main(String[] args) {
     User myuser= registerUser("John", "Doe", "Username", "Password");
      boolean hasExit = true;
      while (hasExit)
      {
         String options = "";
         options = JOptionPane.showInputDialog("The following actions are 
   supported. Enter the code: \nA: Login\nB: Print Users\nC: Exit");
         if (options.equalsIgnoreCase ("A"))
         {
            String username = JOptionPane.showInputDialog("Username");
            String password = JOptionPane.showInputDialog("Password");
            // I would like to check whether the username and password 
      // submitted here are the same as the one used to register  
            // Use userLogin method here to compare the username and password 
    //that is inputted here and the username and password that was created 
    //when registering
            if(myuser.getUsername().equals(username) && 
      myuser.getPassword.equals(password)) { 
                // this is for only created user object by using registerUser 
        // method
                // if you want to check in complete list need to iterate list 
            // here, by using for each or streams 
                System.out.println("user existed or success ");
                hasExit = false;
            }else {
                System.out.println("failed");
                hasExit = false;
            }
         }
         else if (options.equalsIgnoreCase ("B"))  
         {
            listUsers();
           hasExit = false;
         }      
         else if (options.equalsIgnoreCase ("C"))
         {
            hasExit = false;
         }
      }  

   }

但是你仍然可以让这段代码更干净，你也可以编写 switch case 而不是 while 循环

推荐的方法在方法内部编写逻辑并在 main 中调用该方法

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