使用其唯一ID删除ArrayList的对象

Question

我在的功能方面遇到问题ArrayList。我正在尝试通过指定ArrayList的对象来删除它们ID。createEmployee我Main班上有一个方法：

public void createEmployee(){
    String typeofemployee = sc.nextLine();

    UUID uniqueID = UUID.randomUUID();
    String x = "" + uniqueID;
    System.out.println("The new ID of the " + typeofemployee + " is: " + uniqueID + ".");

    System.out.println("What's the name of the new " + typeofemployee + "?");
    name = sc.nextLine();
    System.out.println("What's the salary of the new " + typeofemployee + "?");
    salary = sc.nextDouble();
    Employee employee = new Employee(x, name, salary);

    switch (typeofemployee) {

        case "Employee":
            reusaxcorp.registerEmployee(employee);
            break;

        // other cases
    }
}

我有一个ArrayList，通过使用以下方法注册员工来添加员工（下面是该removeEmployee方法）。

public class ReusaxCorp extends Main {

Scanner input;
ArrayList<Employee> employees = new ArrayList<Employee>();
final String END_OF_LINE = System.lineSeparator();

public void registerEmployee(Employee employee){
    employees.add(employee);
}

public void retrieveEmployee() {
    for(Employee employee: employees){
        System.out.println("ID: " + employee.ID + END_OF_LINE + "Name: " + employee.name + END_OF_LINE + "Salary: " + employee.grossSalary);
        System.out.println(); // an empty line for each employee
    }
}

public void removeEmployee(){
    employees.remove(0); 
    /* I also tried this, but it doesn't work either
    Iterator<Employee> iter = employees.iterator();
    while(iter.hasNext()){
        for (int i = 0; i < employees.size(); i++) {
            System.out.println("Which eployee do you want to remove? Type in his/her ID. ");
            int number = input.nextInt();
            Employee employee = iter.next();
            if (employees.equals(number)) {
                employees.remove(i);
            }
        }
    }
    */
}

我知道的唯一方法就是employees.remove(index)通过指定员工索引来写和删除该员工。因此，我想知道是否可以通过指定雇员的唯一ID来删除其雇员。谢谢。

Answer 1

从 Java 8 开始就有了一个removeIf()方法。您可以按如下方式使用它：

employees.removeIf(employee -> employee.getId().equals(removeId));

Answer 2

使用removeIfJava 8中引入的最短代码。

employees.removeIf(e -> e.getId().equals(id));

您可能还需要考虑使用Map，因为ID是唯一的，然后仅使用ID就可以非常轻松有效地访问（和/或删除）员工。您还可以Map.values()用来将所有员工作为集合（尽管不是List）。

Map<String, Employee> employees = new HashMap<>();
employees.put(e.getId().toString(), e); // Or use UUID directly as key
employees.remove(idToBeRemoved);