我想通过用户输入添加到arrayList

Question

I have been trying to create a small program that prompts the user for input that takes an employee name and salary adds it to an arrayList, then displays options on the screen(eg 0: quit, 1: add, 2: display), reads the input then proceeds based on the input.Displaying would just be(eg Last Name: Smith Salary: £14000. Just need some help to point me in the right direction. I currently have 3 classes Employee, Employee List and Employee Test.

This class prompts the user input.

import java.util.Scanner;
public class Employee {

private String Last_Name;
private int Salary;

public Employee(){
    Scanner inputValues = new Scanner(System.in);

    System.out.print("Enter employee last name: ");
    Last_Name = inputValues.next();

    System.out.print("Enter Employee Salary: " + "£");
    Salary = inputValues.nextInt();
}

public void Display(){

    System.out.printf("Name: " + Last_Name + " " + "Salary: " + Salary);
    System.out.println("\n");
}
}

This class is supposed to be adding the employees to an arraylist but im not sure if im doing it correctly.

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class EmployeeList extends Employee{

private List <Employee> employee =  new ArrayList<Employee>();


 public EmployeeList(Employee person) {
     employee.add(person);
}

 public void DisplayEmployees(){
     System.out.println("Employee:"  + employee.size()); 
     displayList(employee);
 }

 public static void displayList(List employee) {

      } 
}

This is where the main method is

import java.util.Scanner;

public class EmployeeTest {


public static void main(String[] args) {

    Employee employee = new Employee();
    employee.Display();

    EmployeeList empList =  new EmployeeList(employee);
    empList.DisplayEmployees();

    Scanner scanner = new Scanner(System.in); 
    System.out.println("0: quit, 1: add, 2: display");
    String employees = scanner.next(); 

   /* if (employees.equals("1")){
     //not sure how to go back to displaying the user prompts

        break;
    } */

}

}

Answer 1

Few tips I can think of:

1. EmployeeList should not extend Employee . The main rule of OOP is that class A extends class B if B is a A. This is clearly not the case here - employeeList is not an employee, it's a list of employees (In my mind you don't need a class for this, just List<Employee> )

2. I'd separate the logic from the data. meaning - Employee class should only hold the employee's data, not deal with scanning and getting the input from the user. the constructor should be simple in my mind, something like:

    public Employee(String name, int salary) { this.name = name; this.salary = salary; } 

   The logic of getting the data should be outside of this class, either in an EmployeeHandler or in the main itself. Since you put it inside the employee, you are having troubles continuing when some of the logic is in the employee and some in the main.

3. the high-level code should be something like (I'll leave the details to you):
   • show the menu options to the user
   • if he wants to add user, get input for both variables, create the employee object and add it to the list
   • if he wants to display, go over the list and print (the printing can be done overriding toString in Employee class)
   • if he wants to quit, finish
   • continue this loop until he wants to quit

Answer 2

public class Employee {

    private String Last_Name;
    private int Salary;

    public Employee(){

      public String getLName(){
           return Last_Name;
      }

       public void setLName(){
           this.Last_Name = Last_Name;
      }

       public int getSalary(){
           return salary;
      }

       public void setSalary(){
           this.salary = salary;
      }
   }
}

then in your main method you can create the employee object.

public static void main(String[] args){

    Employee employee = new Employee();
    Scanner scanner = new Scanner(System.in); 
    employee.setLName = scanner.next();
    employee.setSalary = scanner.nextInt();

}

If i were you I would just make an arraylist to hold all employees. I would prompt the input option for x amount of times and add to the end of the arraylist. the arraylist would be created as so

ArrayList<Employee> employeeList = new ArrayList<Employee>();

to add to it use add

employeeList.add(employee);

This should be able to get you started

EDIT:

OOPS, made several mistakes. edit with the following. Note that it is employee.setLastName(value) because the method setLastName is part of the employee class and it must be passed a value because we have defined that in the employee class.

    Employee employee = new Employee();
    Scanner scanner = new Scanner(System.in); 
    String tempName = scanner.next();
    int tempSalary = scanner.nextInt();
    employee.setLastName(tempName);
    employee.setSalary(tempSalary); 

EDIT 2:

try to print arraylists as follows. didnt test it. let me know how it works.

 for (int i = 0; i< employeelist.size(); i++){
         Employee temp = values.get(i);
         System.out.println("Last Name: " + temp.getLname() + "Salary: " + temp.getSalary());
 }

Answer 3

I modified my employee class to look like this:

public class Employee {

public String lastName;
private int salary;

public Employee(){
}
public String getLastName() {
    return lastName;
}

public void setLastName(String lastName) {
    this.lastName = lastName;
}

public int getSalary() {
    return salary;
}

public void setSalary(int salary) {
    this.salary = salary;
}

@Override
public String toString(){
    return "Employee Last Name: " + lastName + "\n" + "Employee Salary: " + salary;
}

}

I have modified my EmployeeTest class:

This is my EmployeeTest class:

import java.util.ArrayList;
import java.util.Scanner;

public class EmployeeTest {

static ArrayList<Employee> employeeList = new ArrayList<Employee>();

public static void main(String[] args) {

    for(int i=0;i<5;i++){
        addEmployees(employeeList); 
    } 
   System.out.println(employeeList.toArray());

}

public static void addEmployees(ArrayList<Employee> employeeList){
    Scanner scanner = new Scanner(System.in); 
    System.out.println("0: quit, 1: add, 2: display");
    String options =  scanner.next();
    if(options.equals("1")){

    System.out.print("Enter employee last name: ");
    String lastname = scanner.next();

    System.out.print("Enter Employee Salary: " + "£");
    int salary = scanner.nextInt();

    Employee employee = new Employee();
    EmployeeList.add(employee);
    }

    else if(options.equals("2")){
        for (Employee employee : employeeList){
        /*System.out.println("Name: " + employee.getLastName() +  ", " + "Salary: " + employee.getSalary());*/
            System.out.println(employee);
        }
    }
    else{
        System.exit(0);
    }




}

}

However when i press 2 as my options it doesn't display what is in my arraylist.

I had read that a toString method is used to get those details so i could print them to the screen. And that using this for loop gets each item in the list to display them. Am i missing something here?. Apologies for this dragging on a bit, im just wanting this to work.