通过Java中的用户请求从数组中删除/读取特定元素

Question

有人可以告诉我我的公共Employee deleteEmployeeID和我的公共Employee readEmployeeID方法怎么了 。 用户应该能够删除或阅读有关他们要求的特定员工ID的更多信息。 我似乎找不到这两种方法有什么问题。

子类

package WorkIDServerStorage;

public class EmployeeList{
    private Employee[] theEmployee;
    private int arrayEmployee;

    public EmployeeList(){
        theEmployee = new Employee[100];
        arrayEmployee = 0;
    }

    public EmployeeList(int arraySize){
        theEmployee = new Employee[arraySize];
        arrayEmployee = 0;
    }

    public void setTheEmployee(Employee[] inputTheEmployee){
        theEmployee = inputTheEmployee;
    }

    public void setArrayEmployee(int inputArrayEmployee){
        arrayEmployee = inputArrayEmployee;
    }

    public Employee[] getTheEmployee(){
        return theEmployee;
    }

    public int getArrayEmployee(){
        return arrayEmployee;
    }

    public Employee addEmployeeID(Employee employeeAdd){
        return theEmployee[arrayEmployee++] = employeeAdd;
    }

    public Employee deleteEmployeeID(int employeeDelete){        
        for(int i = employeeDelete + 1; i < theEmployee.length; i++){
            theEmployee[i-1] = theEmployee[i];
        }
        return null;
    }

    public Employee readEmployeeInfo(int employeeRead){
        return theEmployee[employeeRead];
    }

    @Override
    public String toString(){
        StringBuilder sb = new StringBuilder();
        for(int x = 0; x < arrayEmployee; x++){
            sb.append(theEmployee[x].toString()).append("\n");
        }return sb.toString();
    }
}

主班

package WorkIDServerStorage;
import java.util.Scanner;

public class EmployeeListTest{
    public static void main(String[] args){
        EmployeeList EmployeeListObject = new EmployeeList();
        Scanner input = new Scanner(System.in);

        System.out.println("► Initiating Employee Information Server Storage ◄");
        System.out.println("► Type 'EXIT' at any moment to close the program ◄\n");

        for(int x = 1; x < 6; x++){
            Employee EmployeeObject = new Employee("Employee " + x, 1234 + x, 15 + x);
            EmployeeListObject.addEmployeeID(EmployeeObject);
        }
        System.out.println(EmployeeListObject);

        System.out.print("\nType 'ADD' to add a new employee\n");
        System.out.print("Type 'DELETE' to delete an employee record\n");
        System.out.print("Type 'READ' to read the data of an employee ");
        String menuOption = input.next();

        if(menuOption.equalsIgnoreCase("EXIT")){
            EmployeeListObject.toString();
        }else if(menuOption.equalsIgnoreCase("ADD")){
            System.out.print("\nInsert employee ID: ");
            String addEmployeeID = input.next();
            EmployeeListObject.addEmployeeID(addEmployeeID);
        }else if(menuOption.equalsIgnoreCase("DELETE")){
            System.out.print("\nInsert employee ID: ");
            String deleteEmployeeID = input.next();
            EmployeeListObject.deleteEmployeeID(deleteEmployeeID);
        }else if(menuOption.equalsIgnoreCase("READ")){
            System.out.print("\nInsert employee ID: ");
            String readEmployeeID = input.next();
            EmployeeListObject.readEmployeeInfo(readEmployeeID);
        }      
    }
}

Answer 1

我看到的主要问题，可能是也可能不是您的问题的原因，是在您的主班上。 观察当用户要求读取数据时，实际上什么都没有打印到控制台中。

线

EmployeeListObject.readEmployeeInfo(readEmployeeID);

调用方法

public Employee readEmployeeInfo(int employeeRead){
    return theEmployee[employeeRead];
}

它只返回和Employee对象，但从不打印任何内容。 因此，用户将永远无法读取员工数据。

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您代码中的另一个问题是@popiandro的评论。 但是，我认为这不是导致程序中断的原因。

public Employee deleteEmployeeID(int employeeDelete){        
    for(int i = employeeDelete + 1; i < theEmployee.length; i++){
        theEmployee[i-1] = theEmployee[i];
    }
    return null;
}

此方法将始终返回null ，这样做没有任何意义。 将方法设置为void 。

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