java - 在数组列表中添加多个值

Question

我创建了一个类employee。它有四个变量name，id，salary，city。我已经制作了employee类对象的数组列表。当我运行该文件时，它只显示默认值。但我想在我的数组列表中添加多个值。我该怎么办？请帮我解决这个问题，这是我的代码

 import java.util.*;
    public class arraylist {

     public static void main(String[] args) {
        new arraylist();
       }

    public arraylist() {

        List<Employee > listOfEmp = new ArrayList<Employee >();
        Employee  bk1 = new Employee ();
        listOfEmp .add(bk1);

        System.out.println("   emp = " + bk1);
        System.out.println("listOfEmployee(0) = " + listOfEmp.get(0));

    }

    public class Employee {

        String name="sarah";
        int id =102;
        String city="orny";
        int salary=13000;

       // @Override
        public String toString() {
            return "Employee: name = " + name + "; Id = " + id + "; City = " + city + "; Salary = " + salary + "; hashCode = " + hashCode();
        }

    }
}

Answer 1

您已经创建了具有默认字段值的 Employee 类。

您尚未定义任何参数化构造函数或 setter 来保存新的 Employee。看看如何做到这一点:

使用构造函数添加员工；迭代并打印员工列表:

List<Employee> listOfEmp = new ArrayList<Employee>();

// Add employee to list
listOfEmp.add(new Employee("sarah1", 101, "orny", 13000));
listOfEmp.add(new Employee("sarah2", 102, "orny", 13000));
listOfEmp.add(new Employee("sarah3", 103, "orny", 13000));

// Iterate and print employee list
for (Employee employee : listOfEmp)
    System.out.println(employee);

在 Employee 类中添加参数化构造函数:

class Employee {

    private String name;
    private int id;
    private String city;
    private int salary;

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

    // @Override
    public String toString() {
        return "Employee: name = " + name + "; Id = " + id + "; City = " + city
                + "; Salary = " + salary;
    }
}

您还可以定义 setter 方法[在 Employee 类中]来保存实例变量的值。