Question

我的删除方法似乎无法正常运行，因为当用户尝试输入员工姓名时，应用程序无法删除该员工。应该发生的事情如下：

用户使用我编写的名为userInputByName的mnethod输入员工的姓名。
应用程序在商店中搜索此员工。
员工已被删除。

当我打印出员工仍在那里的商店时，步骤3不起作用。

我现在将向您展示我的代码。

MainApp()

//---------------------------------------------------------------------------------------
//  Name:        Case 3: Delete by Name.
//  Description: Choice 3 gives the user an option to delete an employee by name.
//---------------------------------------------------------------------------------------
            case 3:
                System.out.println("Delete by Name.");
                Employee employeeDelete = MenuMethods.userInputByName();
                Store.searchByName(employeeDelete.getEmployeeName());
                System.out.println("Your choice is: "+ employeeDelete);
                Store.remove(employeeDelete);
                break;

员工

//---------------------------------------------------------------------------------------
//  Employee class.
//---------------------------------------------------------------------------------------
public class Employee
{
//---------------------------------------------------------------------------------------
//  Variables to be used in the employee store.
//---------------------------------------------------------------------------------------
    private String employeeName;
    private int employeeId;
    private String employeeEmail;
//---------------------------------------------------------------------------------------
//  Name:        Constructors.
//  Description:
//---------------------------------------------------------------------------------------
    public Employee(String employeeName, int employeeId, String employeeEmail) 
    {
        this.employeeName = employeeName;
        this.employeeId = employeeId;
        this.employeeEmail = employeeEmail;
    }
//---------------------------------------------------------------------------------------
//  Overloading the constructor for the use with userInputByName method.
//---------------------------------------------------------------------------------------
    public Employee(String employeeName) 
    {
        this.employeeName = employeeName;
    }
//---------------------------------------------------------------------------------------
//  Name:   Getters.
//---------------------------------------------------------------------------------------
    public String getEmployeeEmail() 
    {
        return employeeEmail;
    }

    public String getEmployeeName() 
    {
        return employeeName;
    }
    public int getEmployeeId() 
    {
        return employeeId;
    }
//---------------------------------------------------------------------------------------
//  Name:   Setters.
//---------------------------------------------------------------------------------------
    public void setEmployeeEmail(String employeeEmail) 
    {
        this.employeeEmail = employeeEmail;
    }
    public void setEmployeeName(String employeeName) 
    {
        this.employeeName = employeeName;
    }
    public void setEmployeeId(int employeeId)
    {
        this.employeeId = employeeId;
    }

//---------------------------------------------------------------------------------------
//  Name:   toString.
//---------------------------------------------------------------------------------------
    public String toString() 
    {
        return "\t\t\tEmployee\n" +
                "********************************************************************\n"+
                "Employee Name: "+ employeeName +"\n"+ 
                "Employee Id: " + employeeId +"\n"+  
                "Employee Email: " + employeeEmail;
    }
//---------------------------------------------------------------------------------------
}

删除方法

public Employee remove(Employee key) {
        // Remove the Employee by name.
        if (map.containsKey(key))
            return map.remove(key); // if it is there remove and return.
        else
            return null; // if its not there return nothing.
    }

Hashmap声明

HashMap<String, Employee> map;
    private static Scanner keyboard = new Scanner(System.in);

    public EmployeeStore() {
        map = new HashMap<String, Employee

SearchByName

// ---------------------------------------------------------------------------------------
    // Name: Search by Name.
    // //---------------------------------------------------------------------------------------
    public Employee searchByName(String employeeName) {
        Employee employee = map.get(employeeName);
        System.out.println(employee);
        return employee;
    }

UserInput

//---------------------------------------------------------------------------------------
//  Name:        userInputByName.
//  Description: This method is used in the MainApp to give the user capability to search by name.
//---------------------------------------------------------------------------------------
    public static Employee userInputByName() 
    {
        // String temp is for some reason needed. If it is not included
        // The code will not execute properly.
        String temp = keyboard.nextLine();
        Employee e = null;
        System.out.println("Please enter the Employee Name:");
        String employeeName = keyboard.nextLine();

        return e = new Employee(employeeName);

    }

添加到hashmap

//---------------------------------------------------------------------------------------
//   Create a Store named Store and add Employee's to the Store.
//---------------------------------------------------------------------------------------
        EmployeeStore Store = new EmployeeStore();
        Store.add(new Employee("James O' Carroll", 18, "hotmail.com"));

        Store.add(new Employee("Andy Carroll", 1171, "yahoo.com"));

        Store.add(new Employee("Luis Suarez", 7, "gmail.com"));

Answer 1

您的Hashmap被声明为HashMap<String, Employee> map。

如果您想从中移除某些内容，则需要传递String，而不是Employee。尝试类似：

public Employee remove(String key) 
{
    return map.remove(key);
}

在删除密钥之前，无需检查HashMap是否包含密钥。该方法将为您返回null。

编辑：我很惊讶这并没有给你带来编译时错误。

edit2：好的。因此，您要创建Employee对象，然后将其传递到add()方法中。这样很好，但您需要使用add()方法匹配您所做的remove()方法。因此，如果您正在执行EmployeeStore.remove(<employee.getEmployeeName())，那么您应该使add()方法看起来像这样：

public Employee add(Employee input)
{
    return map.put(input.getEmployeeName(), input);
}

如果之前存储了一个Employee对象，则此函数会返回Key对象，但您可以选择忽略该值。使用这样的add()方法可以使其与remove()方法匹配。由于您拥有员工ID号，您甚至可以将Key更改为该整数，因为它可能比名称更独特。

删除方法不删除EmployeeStore的员工

1 个答案: