Question

我目前正在尝试编写一个跟踪公司员工的程序。我有几节课。我目前的问题是打印出NewWorker类型的数组。我的课程如下：

NewWorker.java

public class NewWorker extends Person {
    private static int howManyWorkers = 0;
    public int workerNumber;
    private MyDate dateJoiningCompany;
    private float Salary = 0.0f;
    public Manager Supervisor;

    public NewWorker(String name, String date, double salary) {
        super(name);
        ++howManyWorkers; //Add one to total workers
        dateJoiningCompany = new MyDate(date);
        Salary = (float)salary;
        workerNumber = howManyWorkers;
    }
    public NewWorker(String name, String date) {
        super(name);
        ++howManyWorkers;
        dateJoiningCompany = new MyDate(date);
        workerNumber = howManyWorkers;
    }
    public void setSalary(double salary) {
        Salary = (float)salary;
    }
    public void setSupervisor(Manager supervisor) {
        if(supervisor != null) {
            this.Supervisor = supervisor;
        }
        else {
            System.out.println("The person you are trying to assign a Supervisor to has no supervisor");
        }
    }
    public static int getHowManyWorkers() {
        return howManyWorkers;
    }
    public Name getSupervisorName() {
        return Supervisor.getPersonName();
    }
    public float getSalary() {
        return Salary;
    }
    public Name toString(NewWorker[] nw) {
        return super.getPersonName();
    }
    public String toString() {
            return ("Worker Number " + workerNumber + " " + super.toString() + " " + "Date Joined Company = " + dateJoiningCompany.toString() 
                    + " " + "Salary = " + Salary);
    }
    public String getDate() {
        return dateJoiningCompany.toString();
    }
}

Person.java

public class Person {
    private Name personName;
    private Person spouse = null;
    public Person(String fullName) {
        personName = new Name(fullName);
    }
    public void setSpouse(Person spouse) {
        this.spouse = spouse;
    }
    public void setSpouse(NewWorker spouse) {
        this.spouse = spouse;
    }

    public String toString() {
        if(spouse !=  null) {
            return ("Name is " + getPersonName().toString() + " Married to " + spouse.getPersonName().toString());
        }
        else {
            return ("Name is " + getPersonName().toString());
        }
    }
    public float getFamilyIncome() {
        if(this instanceof NewWorker) {
            if(this.spouse == null){
                return ((NewWorker)this).getSalary();
            }
            else {
                return ((NewWorker)this).getSalary() + ((NewWorker)this.spouse).getSalary();
            }
        }
        return 0.0f;
    }

    public Name getPersonName() {
        return personName;
    }

    public void setPersonName(Name personName) {
        this.personName = personName;
    }
}

Manager.java

   import java.util.Arrays;

public class Manager extends NewWorker {
    NewWorker[] employeesSupervised = new NewWorker[10];
    private int numWorkersSupervised = 0;

    public Manager(String name, String date, double salary) {
        super(name, date, salary);
    }

    public Manager(String name, String date) {
        super(name, date);
    }

    public double getSalary(double salary) {
        return this.getSalary() + (100 * numWorkersSupervised);
    }

    public void addWorker(NewWorker w) {
        employeesSupervised[numWorkersSupervised] = w;
        numWorkersSupervised++;
    }

    public void deleteWorker(NewWorker w) {
        for(int a = 0; a < numWorkersSupervised; ++a) {
            if(employeesSupervised[a].equals(w)) {
                   int numElements = employeesSupervised.length - ( a + 1 );
                   System.arraycopy( employeesSupervised, a + 1, employeesSupervised, a, numElements);
            }
        }
    }

    public int equals(NewWorker w) {
        if (this == w) {
            return 1;
        }
        else {
            return 0;
        }
    }

    public String toString() {
        if(Supervisor != null) {
            return "Employee Number = " + this.workerNumber + " Name is " + this.getPersonName() + " Date joined company = "
                + this.getDate() + " Supervisor is " + this.getSupervisorName() + " Salary = " + getSalary((double)getSalary())
                + " Workers supervised: " + Arrays.toString(employeesSupervised);
        }
        else {
            return "Employee Number = " + this.workerNumber + " Name is " + this.getPersonName() + " Date joined company = "
                    + this.getDate() + " Salary = " + getSalary((double)getSalary());
        }
    }
}

所以我的阵列试图抓住经理正在观看的所有人/老板。所以当我使用文件

运行我的程序时

test.java

public class test {
    public static void main(String[] args) {
        NewWorker w1, w2, w3, w4;
        Manager m1, m2;
        w1 = new NewWorker("Jack Vanier", "01/01/11", 50000.00);
        w2 = new NewWorker("Robert Perry Fletcher", "02/02/02");
        w3 = new NewWorker("Hannah Burdett", "05/05/05");
        w4 = new NewWorker("Mitchell John McDonagh", "12/12/12", 25000.0);

        m1 = new Manager("Sydney Chapados", "11/11/11", 75000);
        m2 = new Manager("Steph Scane", "10/10/01", 80000);

        m1.addWorker(w1);
        m1.addWorker(w2);
        m1.addWorker(w3);
        m2.addWorker(w4);
        m2.addWorker(w1);

        w1.setSpouse(w3);
        w3.setSpouse(w1);

        w2.setSupervisor(m1);
        w1.setSupervisor(m1);
        w4.setSupervisor(m2);
        m2.setSupervisor(m1);

        System.out.println(w1);
        System.out.println(w2);
        System.out.println(w3);
        System.out.println(w4);

        System.out.println(m1);
        System.out.println(m2);
    }

}

我得到了前四个（所有工人）的正确输出，但对于我的经理，我无法正确地打印出那些工人。这两个问题是它打印出整个员工信息（姓名，日期，加入工人号码等），我只希望它打印员工姓名，但无法弄清楚如何做到这一点。

另一个问题是，由于我的数组不完整，因此在调用Array.toString（）时会得到一堆空值。我怎样才能摆脱这些空值？

Answer 1

因为这一行：

NewWorker[] employeesSupervised = new NewWorker[10];

数组中没有足够的元素，这就是输出null

的原因

Answer 2

如果您只想在打印管理器时使用员工姓名，那么请使用to string方法的Person实现。然而，访问超类的超级并不是一件简单的事情，你需要将每个相对基类中的引用存储到超类中，然后调用super.superClass.super.SuperClass.toString（）来获取Person toString（）

Answer 3

Arrays.toString在这里不合适，也不是任何开箱即用的解决方案。例如，您似乎不想在任何意义上实际使用toString，因为您只需要名称。这是Java 8的解决方案：

+ " Workers supervised: " + 
    Arrays.stream(employeesSupervised)
          .filter(Objects::nonNull)
          .map(NewWorker::getPersonName)
          .collect(Collectors.joining(", "));

如何在类数组上调用toString方法

3 个答案: