Java 继承-从class Employee和testing创建一个class Commission Employee

早上好，我被指派到： 将CommissionEmployee类重写为Employee的子类。CommissionEmployee应仅包含超类Employee中未声明的实例变量和方法。CommissionEmployee的构造函数应该调用Employee的构造函数，CommissionEmployee的toString方法应该调用Employee的toString方法。 创建一个驱动程序类来测试新的CommissionEmployee类。提示用户输入名字、姓氏、社会保险号码、总销售额和佣金率，并使用toString方法打印其信息，创建CommissionEmployee对象。 我似乎遇到的问题是，类CommissionEmployeeTest不会输出我在类CommissionEmployee的toString方法中放置的内容。我觉得我的超类雇员和我的测试类一样都是正确的，但我认为错误在于我创建的确定收入的方法中的某个地方。我想要的输出是 员工姓名 社会保险号码 收益 收入将是总销售额+的总和（佣金率*总销售额） 以下是我的错误信息：

class Employee
public class Employee extends Object {

    protected final String firstName;
    protected final String lastName;
    protected final String socialSecurityNumber;

    public Employee(String firstName, String lastName, String socialSecurityNumber) {
        this.firstName = firstName;
        this.lastName = lastName;
        this.socialSecurityNumber = socialSecurityNumber;
    }

    public String getFirstName() {
        return firstName;
    }

    public String getLastName() {
        return lastName;
    }

    public String getSocialSecurityNumber() {
        return socialSecurityNumber;
    }

    @Override

    public String toString() {
        return String.format(firstName, lastName, socialSecurityNumber);
    }
}

错误 通过get方法获取的员工信息： 输入员工的名字：John 输入员工的姓氏：Doe 输入员工的社会保险号码：123456789 员工总销售额：4000.00 员工的佣金率：.1 线程“main”java.lang.StackOverflowerr中出现异常 收入（CommissionEmployee.java:45）

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我试着在CommissionEmployee中运用我的toString方法以及我确定收入的方法，但我觉得我在旋转轮子。谢谢你的帮助。我还有一周的时间上课，我觉得当我每周发布一个问题时，我可以提供更多的信息，而不是上一个问题。提前谢谢。

我已经解决了这个问题。经过（几次）复习和修改，我找到了我的答案。我需要修改我的toString方法和收入方法。清理了大量代码并解决了问题。

没有与实例变量同名的方法。

class CommissionEmployee
public class CommissionEmployee extends Employee {

    private double grossSales;
    private double commissionRate;
    private double earnings;

    public CommissionEmployee(String firstName, String lastName, String socialSecurityNumber, double grossSales,
            double commissionRate, double earnings) {
        super(firstName, lastName, socialSecurityNumber);       

        if (grossSales < 0.0)
            throw new IllegalArgumentException("Gross sales must be >= 0.0");

        if (commissionRate <= 0.0 || commissionRate >= 1.0)
            throw new IllegalArgumentException("Commission rate must be > 0.0 and < 1.0");

        this.grossSales = grossSales;
        this.commissionRate = commissionRate;
    }

    public void setGrossSales(double grossSales) {

        if (grossSales < 0.0)
            throw new IllegalArgumentException("Gross sales must be >= 0.0");
        this.grossSales = grossSales;
    }

    public double getGrossSales() {
        return grossSales;
    }

    public void setCommissionRate(double commissionRate) {

        if (commissionRate <= 0.0 || commissionRate >= 1.0)
            throw new IllegalArgumentException("Commission rate must be > 0.0 and < 1.0");
        this.commissionRate = commissionRate;
    }

    public double getCommissionRate() {
        return commissionRate;
    }


    public Double earnings(double d) {
        return earnings(grossSales+ (commissionRate * grossSales));
    }

    public double getEarnings() {
        return earnings;
    }

    public void setEarnings(double earnings) {
        this.earnings = earnings;
    }
    @Override

    public String toString() {

        return String.format("%s: %s %s%n%s: %s%n%s: %.2f%n%s: %.2f%n%s: %.2f%n%s",
                "commission employee", firstName, lastName,
                "social security number", socialSecurityNumber,
                "Total earnings", earnings(earnings));
    }

    public void setFirstName(String firstName) {
    }

    public void setLastName(String lastName) {
    }

    public void setSocialSecurityNumber(String socialSecurityNumber) {
    }

    public void setGrossSales(String grossSales) {  
    }

    public void setCommissionRate(String commissionRate) {
    }
}

class CommissionEmployeeTest
  //CommissionEmployee test program.
 import java.util.Scanner;

  public class CommissionEmployeeTest {
     public static void main(String[] args) { // instantiate CommissionEmployee object

        CommissionEmployee employee =  
           new CommissionEmployee(null, null, null, 0, .1, 0);

        Scanner input = new Scanner(System.in);

       // get commission employee data
       System.out.printf(
          "Employee information obtained by get methods:%n");

       System.out.printf("Enter employee's First name:");
               String firstName = input.nextLine();
               employee.setFirstName(firstName);

       System.out.printf("Enter employee's last name:");
               String lastName = input.nextLine();
               employee.setLastName(lastName);

       System.out.printf("Enter employee's social security number:");
               String socialSecurityNumber = input.nextLine();
               employee.setSocialSecurityNumber(socialSecurityNumber);

       System.out.printf("Gross sales for employee:");
               String grossSales = input.nextLine();
               employee.setGrossSales(grossSales);

       System.out.printf("Commission rate for employee:");
               String commissionRate = input.nextLine();
               employee.setCommissionRate(commissionRate);         

        System.out.printf("%n%s:%n%n%s%n",
            "Updated employee information obtained by toString",                          

          employee.toString());
    }
  }