对另一个类中的非静态方法进行静态引用

时间:2016-04-01 02:18:18

标签: java arrays class oop class-design

我正在Java课程中学习面向对象的编程,我正在做一个程序创建三种类型对象的项目:Address,Date和Employee。该程序存储多个员工的数据,然后以Employee类型的数组显示数据。

我使用了四个不同的类:Address类,Date类和Employee类,以及创建数组的EmployeeTest类。< / p>

这是Address类:

public class Address {

    private String Street;
    private String City;
    private String State;
    private int ZipCode;

    public Address(String St, String Ci, String Sta, int Zip){
        Street = St;
        City = Ci;
        State = Sta;
        ZipCode = Zip;
    }

    public String getEmployeeAddress(){
        return (Street + ", " + City + ", " + State + " " + ZipCode);
    }
}

日期类:

public class Date {

    private int Month;
    private int Day;
    private int Year;

    public Date(int M, int D, int Y){
        Month = M;
        Day = D;
        Year = Y;
    }

    public String getDateString(){
        return (Month + "/" + Day + "/" + Year);
    }
}

而且,员工类:

public class Employee {
    private int EmployeeNum;

    public void setEmployeeNum(int ENum){
        EmployeeNum = ENum;
    }

    public int getNum(){
        return EmployeeNum;
    }

    public String getDate(){
        return Date.getDateString();
    }

    public String getName(){
        return Name.getEmployeeName();
    }
    public String getAddress(){
        return Address.getEmployeeAddress();
    }

}

所有这些类都在同一个包中(我正在使用Eclipse)。 Employee类的要点是创建一个Employee类型的对象,并且能够使用Address,Name和Date类来获取它的Address,Name和HireDate。

阵列发挥作用的地方在这里:

import java.util.Scanner;
import java.lang.*;

public class EmployeeTest {

    public static void main(String[] args){
        Scanner input = new Scanner(System.in);
        System.out.print("How many employees will have their data stored today?");
        int EmployeeAmount = Integer.parseInt(input.nextLine());

        Employee [] EmployeeArray = new Employee[EmployeeAmount];

        for (int i = 0; i < EmployeeArray.length; i ++){
            System.out.print("What is employee " + (i+1) + "'s employee number?");
            int EmployeeNumber = Integer.parseInt(input.nextLine());
            EmployeeArray[i] =  new Employee();
            EmployeeArray[i].setEmployeeNum(EmployeeNumber);

            System.out.println("What is the first name of employee " + EmployeeNumber + "?");
            String EmployeeFirstName = input.nextLine();

            System.out.println("What is the last name of employee " + EmployeeNumber + "?");
            String EmployeeLastName = input.nextLine();

            Name EmployeeName = new Name(EmployeeFirstName, EmployeeLastName);

            System.out.println("Please enter the street address: ");
            String StreetAddress = input.nextLine();
            System.out.println("Please enter the name of the city: ");
            String CityName = input.nextLine();
            System.out.println("Please enter the two character code for the state: ");
            String StateID = input.nextLine();
            System.out.println("Please enter this address's zip code: ");
            int ZipCode = Integer.parseInt(input.nextLine());

            Address EmployeeAddress = new Address(StreetAddress, CityName, StateID, ZipCode);

            System.out.println("Finally, what was the month(#) of the hire date?");
            int Month = Integer.parseInt(input.nextLine());
            System.out.println("What was the day(#)?");
            int Day = Integer.parseInt(input.nextLine());
            System.out.println("What was the year?");
            int Year = Integer.parseInt(input.nextLine());

            Date HireDate = new Date(Month, Day, Year);



        }

        for (int j = 0; j < EmployeeArray.length; j ++){
            System.out.println("Employee number: " + EmployeeArray[j].getNum());
            System.out.println("Employee Name: " + EmployeeArray[j].getName());
            System.out.println("Employee Address: " + EmployeeArray[j].getAddress());
            System.out.println("Employee Hiredate: " + EmployeeArray[j].getDate());
        }


    }

}

程序会提示用户输入要存储在数组中的员工数,然后创建大小为Employee[]的{​​{1}}。代码的想法是,对于Array中的每个Employee,获得其他类中的所有变量:Employee Number,Employee Name(first and last),Address(Street Address,City,State Code,Zip Code),雇用日期(月,日,年)。获得所有这些后,第二个EmployeeAmount循环遍历每个Employee并显示信息。

我遇到的问题是,在for类中,Eclipse在EmployeegetDate()getName()方法中给出了错误。当我说getAddress()时,Eclipse说我无法对非静态方法进行静态引用。它的解决方案是使return Date.getDateString()静态,我尝试了这个,但问题是通过在Address,Employee和Date类中创建所有方法和变量,值被锁定。这意味着将为所有员工显示相同的数据。

这就是我的意思。下面是一个示例输出,如果我将所有方法和变量设置为静态。星号之间的文本是用户输入的内容。

getDateString()

通过使所有变量和方法保持静态,值如图所示被锁定,这使得程序无用。有没有人有这个问题的解决方案?我需要一种方法来显示每个员工的信息,同时引用其他类中的方法。现在,通常我会在一个名为How many employees will have their data stored today?**2** What is employee 1's employee number?**1** What is the first name of employee 1? **Bob** What is the last name of employee 1? **Jones** Please enter the street address: **300 1st Avenue** Please enter the name of the city: **New York** Please enter the two character code for the state: **NY** Please enter this address's zip code: **10001** Finally, what was the month(#) of the hire date? **1** What was the day(#)? **1** What was the year? **2001** What is employee 2's employee number?**2** What is the first name of employee 2? **Bobby** What is the last name of employee 2? **Robinson** Please enter the street address: **301 1st Avenue** Please enter the name of the city: **Los Angeles** Please enter the two character code for the state: **CA** Please enter this address's zip code: **90001** Finally, what was the month(#) of the hire date? **1** What was the day(#)? **2** What was the year? **2004** Employee number: 2 Employee Name: Bobby Robinson Employee Address: 301 1st Avenue, Los Angeles, CA 90001 Employee Hiredate: 1/2/2004 Employee number: 2 Employee Name: Bobby Robinson Employee Address: 301 1st Avenue, Los Angeles, CA 90001 Employee Hiredate: 1/2/2004的类下创建所有变量和方法,但是赋值指令指定我需要创建单独的类。

1 个答案:

答案 0 :(得分:1)

您正在为for循环的每次迭代创建NameAddressDate。但是你没有办法,也没有在每个Employee实例上设置它们。

您需要添加方法来设置每个Employee上的值并存储信息。像这样:

public class Employee {
    private int employeeNum;
    private Name name;
    private Date hireDate;
    private Address address;


    public void setEmployeeNum(int eNum){
        employeeNum = eNum;
    }

    public int getEmployeeNum(){
        return employeeNum;
    }

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

    public String getHireDate(){
        return hireDate.getDateString();
    }

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

    public String getName(){
        return name.getEmployeeName();
    }

    public void setAddress(Address addy){
        this.address = addy;
    }

    public String getAddress(){
        return address.getEmployeeAddress();
    }
}

然后在你的for循环中,设置值:

  EmployeeArray[i].setName(EmployeeName);
  EmployeeArray[i].setAddress(EmployeeAddress);
  EmployeeArray[i].setHireDate(HireDate);

顺便说一下,你不应该把变量,只有类大写。 变量应该是驼峰式的。