Question

我正在尝试查看用户在方法addUser（）中输入的密码是否与在方法deleteUser（）中输入的密码匹配。这两种方法都会查看充满了FacebookUser对象的用户数组列表，但是，我无法弄清楚如何从每种方法中匹配适当的密码。

我尝试了多个代码，我什至不记得了，有时候即使正确，我也总是会返回“不正确的密码”。但是只要我在数组列表中只有一个对象，它就可以工作，直到我添加另一个用户为止。这将使两个用户最终使用相同的密码。

public class Facebook extends FacebookUser implements Serializable {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    Scanner input = new Scanner(System.in);
    private ArrayList<FacebookUser> users;

    public Facebook(String username, String password) {
        super(username, password);
        users = new ArrayList<>();

    }

    // prints users
    public void listUsers() {
        if( users.isEmpty())
        {
            System.out.println("List is empty");
        }
        else
        {
            for (FacebookUser users : this.users)

            {
            System.out.println("Username: " + users.getUsername());
            }
        }
    }


    // adds a user

    public void addUser() {

        //creating an instance of FacebookUser class
        FacebookUser user1 = new FacebookUser();

        System.out.println("Enter username to add: ");
        String newUser = input.nextLine();
        user1.setUsername(newUser);
    // using the setter method in UserAccount to set the username for "fb" object


        //if statement checks if any object contains the same username  
        if (users.contains(user1)) { 
            System.out.println("Error, username already exists");

        } 
        else {

            System.out.println("Please enter password: ");
            String password = input.nextLine();
            System.out.println("Please enter password hint: ");
            String passwordHint = input.nextLine();

            FacebookUser user2 = new FacebookUser();
            //creating another object for the "official" new user

            user2.setPassword(password);
            user2.setUsername(newUser);
            user2.setPasswordHint(passwordHint);

            users.add(user2);

            System.out.println(newUser + " has been added");

        }
    }

    // deletes a user
    public void deleteUser() {

    FacebookUser user1= new FacebookUser();
    System.out.println("Enter username you want to remove: ");
    String removeUser = input.nextLine();   


    user1.setUsername(removeUser);



        if (users.contains(user1)) {
            System.out.println("Enter password");
            String checkPassword = input.nextLine();
                    user1.setPassword(checkPassword);

            if (user1.password.equals(checkPassword)) {
                users.remove(user1);
                System.out.println(removeUser + " has been removed");
            } else {
                System.out.println("Incorrect password");
            }
        } else {
            System.out.println("User does not exist");

        }
    }

Answer 1

问题是，在deleteUser()中，您正在将用户输入的密码设置为user1，然后用if (user1.password.equals(checkPassword))检查密码。因此，此if条件始终为true。

我在下面的代码中注释了不必要的行。

（我假设您在equals()类中正确地重写了FacebookUser方法。因为contains()和remove()方法依赖于equals()方法。）

public void deleteUser() {

FacebookUser user1= new FacebookUser();
System.out.println("Enter username you want to remove: ");
String removeUser = input.nextLine();   


user1.setUsername(removeUser);



    if (users.contains(user1)) {
        System.out.println("Enter password");
        String checkPassword = input.nextLine();
                // I commented this line
                //user1.setPassword(checkPassword);

        if (user1.password.equals(checkPassword)) {
            users.remove(user1);
            System.out.println(removeUser + " has been removed");
        } else {
            System.out.println("Incorrect password");
        }
    } else {
        System.out.println("User does not exist");

    }
}

Answer 2

如果不覆盖包含的实现，则代码将无法工作。尝试类似的事情。

    public void deleteUser() {

        FacebookUser user1= new FacebookUser();
        System.out.println("Enter username you want to remove: ");
        String removeUser = input.nextLine();  
        boolean isPresent = false; 
        for(FacebookUser user:users){
        if(user.getUsername.equals(removeUser)){
                isPresent = true;
            System.out.println("Enter Password");
            password = sc.nextLine();
            if(user.getPassword.equals(password)){
                users.remove(user);
                break;
            }else{
            System.out.println("Incorrect Password");
            }
        }
        }
        if(!isPresent){
        System.out.pritln("User does not exist");
        }
        }

Answer 3

尝试一下。当您使用user.contain（user1）时，它将比较user 1中user 1的所有字段。即它将检查用户名和密码与user1相同的用户。但是之前未为此用户1设置密码。因此，它将永远不会在列表中找到它。

，并且在arraylist上使用.remove（）时，它将index作为参数。因此，始终传递要删除的用户而不是用户的索引。

如果仍然有任何错误，请在评论中发布错误，然后我会告诉您解决方法。

public void deleteUser() {

    FacebookUser user1= new FacebookUser();
    System.out.println("Enter username you want to remove: ");
    String removeUser = input.nextLine();   

    int i=0;
    for(FacebookUser users:this.users)
    {
        boolean present = false;
        if(users.getUserName().equals(removeuser))
        {
            present = true;
            System.out.println("Enter password");
            String checkPassword = input.nextLine();
                    users.setPassword(checkPassword);
            if(users.getPassword().equals(checkPassword))
            {
                  this.users.remove(i);
                  System.out.println(removeUser + " has been removed");
                  break;
            }
            else
                System.out.println("Incorrect password");


        }
        i++;
    }
    if(!present)

        System.out.println("User does not exist");

}

如何查看密码是否与对象的数组列表匹配

3 个答案: