配列への新しい参照の追加？

Question

私は3 parameters：Employees(firstNames, lastNames, idNumbers)を受け入れる配列を持っています。これは文字列配列です。

String[] firstNames= {"Fred","John","Amir", "James","Bob","Jay","Amber"}; 
String[] lastNames = {"Bond","Kates","Memar", "White","Marley","Brown","Nogofski"}; 
String[] idNumbers = {"R111111","A222222","AB11111", "KR22121","V311133","L242434","P102432"}; 
String[] employeeNum = {"1111","2222","3333", "4444","5555","6666","7777"}; 

私は私の印刷メソッドを呼び出すとき、私は出力を得る：

First name: Fred 
Last name: Bond 
Id number: R111111 
Employee number: No employee number has been assigned yet! 

First name: John 
Last name: Kates 
Id number: A222222 
Employee number: No employee number has been assigned yet! 

のように...

あなたはまだ割り当てられた従業員番号がありません見ることができるように。しかし、私は私のassignEmployeeNum()メソッドを使用する場合、従業員の数は、文字列配列内の番号に変更する必要があります。

String[] employeeNum = {"1111","2222","3333", "4444","5555","6666","7777"}; 

をしかし、その代わりに、私はこの出力を得る：

+++After adding the employee number to the list+++ 

First name: null 
Last name: null 
Id number: null 
Employee number: 1111 

First name: null 
Last name: null 
Id number: null 
Employee number: 2222 

のように...

この問題の私の最初の試みは、従業員番号専用の別のコンストラクタを追加していたに過ぎません。任意のアドバイスをいただければ幸いです。

mainメソッド

public static void main(String[] args) 
{ 
String[] firstNames= {"Fred","John","Amir", "James","Bob","Jay","Amber"}; 
String[] lastNames = {"Bond","Kates","Memar", "White","Marley","Brown","Nogofski"}; 
String[] idNumbers = {"R111111","A222222","AB11111", "KR22121","V311133","L242434","P102432"}; 
String[] employeeNum = {"1111","2222","3333", "4444","5555","6666","7777"}; 

Employee[] list = new Employee[firstNames.length]; 
list = listOfEmployees(firstNames,lastNames,idNumbers); // create the list of employees in one array 
printEmployeeList(list); //print the list of employees 
list = assignEmployeeNum(list,employeeNum); // assign the employee number to the employees 

Employeeクラス

public static class Employee{ 
    private String firstName; 
    private String lastName; 
    private String idNumber; 
    private String employeeNumber; 
    private int employeeCount; 

    /** 
    * Constructor 
    * @param firstName first name 
    * @param lastName last name 
    * @param idNumber id number 
    */ 
    public Employee(String firstName, String lastName, String idNumber){ 
     this.firstName = firstName; 
     this.lastName = lastName; 
     this.idNumber = idNumber; 
     employeeCount = 0; 
    } 

    public Employee(String EmployeeNum){ 
     this.employeeNumber = EmployeeNum; 
    } 
    /** 
    * Accessors here 
    */ 

    public String getFirstName(){ 
     return firstName; 
    } 

    public String getLastName(){ 
     return lastName; 
    } 

    public String getIdNumber(){ 
     return idNumber; 
    } 

    public String getEmployeeNumber(){ 
     return employeeNumber; 
    } 

    // mutators here 

    /** 
    * @param firstName first name 
    */ 
    public void setFirstName(String firstName){ 
     this.firstName = firstName; 
    } 

    /** 
    * @param lastName last name 
    */ 
    public void setLastName(String lastName){ 
     this.lastName = lastName; 
    } 

    /** 
    * @param idNumber id number 
    */ 
    public void setIdNumber(String idNumber){ 
     this.idNumber = idNumber; 
    } 

    /** 
    * @param employeeNumber employee number 
    */ 
    public void setEmployeeNumber(String employeeNumber){ 
     this.employeeNumber = ""; 
    } 
    @Override 
    public String toString(){ 
     String result = "\nFirst name: " + getFirstName() + "\nLast name: " + getLastName() 
       + "\nId number: " + getIdNumber() + "\nEmployee number: "; 
     if(getEmployeeNumber() == null){ 
     return result + "No employee number has been assigned yet!\n"; 
    } 
     return result + getEmployeeNumber() + "\n"; 
    } 

} 

割り当て社員方法

public static Employee[] assignEmployeeNum(Employee[] list, String[] number){ 
for(int i = 0; i<list.length; i++){ 
     list[i] = new Employee(number[i]); 
} 
return list;  
} 

Answer 1

あなたがしているCR assignEmployeeメソッド内で完全に新しいEmployeeオブジェクトを使用します.1つは、配列にすでに存在するものを使用するのではなく、すべてのフィールドにnull値を持ちます。解決策：それをしないでください。代わりに、その位置にある配列に保持されている現在のEmployeeオブジェクトを取得し、メソッド内に従業員IDを設定するだけです。

例えば、

public static Employee[] assignEmployeeNum(Employee[] list, String[] number){ 
    for(int i = 0; i<list.length; i++){ 
     list[i].setEmployeeNumber(number[i]); 
    } 
    return list;  
} 

Answer 2

代わりの

list[i] = new Employee(number[i]); 

あなたはあなただけの従業員番号を持つ新しいEmployeeオブジェクトを作成し、あなたのコードで

list[i].setEmployeeNumber(number[i]); 

を使用する必要があります。 変更されたコードでは、既存の従業員を使用して従業員番号を設定します。