java - 我需要帮助，我的 java 程序在编译时没有返回任何内容

Question

我是一名正在做 Java 作业的大学生。我创建了这个允许用户输入工作信息的程序。

问题是我的程序没有返回输入的信息。

我看了一会儿我的程序，但我知道我错过了一些简单的东西。

public class Employee 
{
    String name;             // Employee name
    String employeeNumber;   // Employee number
    String hireDate;         // Employee hire date
    int shift;                   // Employee shift
    double payRate; 

    public void setEmployeeNumber(String e)
    {
       if (isValidEmpNum(e))
       {
          employeeNumber = e;
       }
       else
       {
          employeeNumber = "";
       }
    }

    public Employee(String name, String e, String hireDate, double payRate, int shift)
    {
       this.name = name;
       this.setEmployeeNumber(e);
       this.hireDate = hireDate;
       this.payRate = payRate;
       this.shift = shift; 
    }

    public Employee()
    {
       name = "";
       employeeNumber = "";
       hireDate = "";
    }

    public void setpayRate(double payRate)
    {
       this.payRate = payRate;
    }

    public double getpayRate()
    {
       return payRate;
    }

    public void setshift(int shift)
    {
       this.shift = shift;
    }

    public int getshift()
    {
       return shift;
    }


    public void setName(String name)
    {
       this.name = name;
    }

    public void setHireDate(String hireDate)
    {
       this.hireDate = hireDate;
    }

        public String getName()
    {
       return name;
    }

    public String getEmployeeNumber()
    {
       return employeeNumber;
    }

    public String getHireDate()
    {
       return hireDate;
    }

    private boolean isValidEmpNum(String e)
    {
       boolean status = true;

       if (e.length() != 5)
          status = false;
       else
       {
         if ((!Character.isDigit(e.charAt(0)))  ||
            (!Character.isDigit(e.charAt(1)))   ||
            (!Character.isDigit(e.charAt(2)))   ||
            (e.charAt(3) != '-')                ||
            (!Character.isLetter(e.charAt(4)))  ||
            (!(e.charAt(4)>= 'A' && e.charAt(4)<= 'M')))
          {
             status = false;
          }
       }
       return status;
    }
    public String toString()
    {
       String str = "Name: " + name + "\nEmployee Number: ";

       if (employeeNumber == "")
       {
          str += "INVALID EMPLOYEE NUMBER";
       }
       else
       {
          str += employeeNumber;
       }

       str += ("\nHire Date: " + hireDate);
       return str;
    }  
}

我在另一个类中声明了这一点。

import javax.swing.JOptionPane;

public class ProductionWorkerDemo extends Employee 
{
    public static void main(String[] args)
    {
       String name;             // Employee name
       String employeeNumber;   // Employee number
       String hireDate;         // Employee hire date
       int shift;                    // Employee shift
       double payRate;               // Employee pay
       String str;
       String str2;


       name = JOptionPane.showInputDialog("Enter your name: ");

       employeeNumber = JOptionPane.showInputDialog("Enter your employee number: ");

       hireDate = JOptionPane.showInputDialog("Enter your hire date: ");

       str = JOptionPane.showInputDialog("Enter your shift: ");

       payRate = Double.parseDouble(str);

       str2 = JOptionPane.showInputDialog("Enter your payrate: ");

       payRate = Double.parseDouble(str2);

       ProductionWorkerDemo pw = new ProductionWorkerDemo();

        System.out.println();
        System.out.println("Name: " + pw.getName());
        System.out.println("Employee Number: " + pw.getEmployeeNumber());
        System.out.println("Hire Date: " + pw.getHireDate());
        System.out.println("Pay Rate: " + pw.getpayRate());
        System.out.println("Shift: " + pw.getshift());

    }
}

Answer 1

您需要使用适当的构造函数或 set* 方法来设置对象的字段。目前，它们都是空的，因此 get* 方法不返回任何内容或返回默认值。

此外，您不应该使用包含 main 方法的类来扩展 Employee，只需直接使用 Employee 类即可(从类继承背后的想法是扩展它，在你的情况下你只需要它作为一个对象来保存数据，所以不要从它派生而是使用它):

import javax.swing.JOptionPane;

public class ProductionWorkerDemo
{
    public static void main(String[] args)
    {
       String name;             // Employee name
       String employeeNumber;   // Employee number
       String hireDate;         // Employee hire date
       int shift;                    // Employee shift
       double payRate;               // Employee pay
       String str;
       String str2;


       name = JOptionPane.showInputDialog("Enter your name: ");

       employeeNumber = JOptionPane.showInputDialog("Enter your employee number: ");

       hireDate = JOptionPane.showInputDialog("Enter your hire date: ");

       str = JOptionPane.showInputDialog("Enter your shift: ");

       payRate = Double.parseDouble(str);

       str2 = JOptionPane.showInputDialog("Enter your payrate: ");

       payRate = Double.parseDouble(str2);

       Employee pw = new Employee(/*provide arguments here*/);

        System.out.println();
        System.out.println("Name: " + pw.getName());
        System.out.println("Employee Number: " + pw.getEmployeeNumber());
        System.out.println("Hire Date: " + pw.getHireDate());
        System.out.println("Pay Rate: " + pw.getpayRate());
        System.out.println("Shift: " + pw.getshift());

    }
}