對象的一個​​ArrayList列出參數

Question

我想創建一個方法來列出一個ArrayList中的元素，但該方法只返回最新的對象的值：

對象：

//Constructor for guests at the hotel 
public Guest (String name, String checkinDate, String checkoutDate, double depAmt) 
{ 
    gstName = name; 
    checkIn = checkinDate; 
    checkOut = checkoutDate; 
    deposit = depAmt; 
} 

ArrayList中當前對象：

//Fills the roster with three guests to start the program 
public static void fillGuest() 
{ 
    Guest guest1 = new Guest("Mike P.", "2/13/16", "2/23/16", 360.00); 
    guestList.add(guest1); 
    Guest guest2 = new Guest("Randall M.", "4/10/16", "4/17/16", 120.00); 
    guestList.add(guest2); 
    Guest guest3 = new Guest("Bo-Diddly.", "4/20/16", "4/23/16", 600.00); 
    guestList.add(guest3); 
} 

方法列出ArrayList中的對象：

public static void returnGuests() 
{ 
    System.out.println("Currently checked in " + guestList.size() + " guests:"); 
    for (int i = 0; i <= guestList.size() - 1; i++) 
    { 
     System.out.println(guestList.get(i)); 
    } 
} 

輸出：

Currently checked in 3 guests: 
Bo-Diddly. 4/20/16 4/23/16 600.0 
Bo-Diddly. 4/20/16 4/23/16 600.0 
Bo-Diddly. 4/20/16 4/23/16 600.0 

Enter command: 

如何顯示每個客戶對象的單個對象的參數？

Answer 1

你Guest對象應該如下。請注意，字段中缺少static修飾符。另請注意，使用this關鍵字。如果您使用的是帶有static變量，那麼你的IDE應該給你一個警告，它會被解釋爲MyClass.var，而不是this.var。

您的問題是，當您創建新的Guest對象時，所有Guest對象將具有最後一組變量。您需要使用「實例」變量而不是「類」變量。

如果您想了解更多關於靜態「類」變量的話題，請參閱Understanding Class Members。

public class Guest { 

    String gstName, checkIn, checkOut; 
    double deposit; 

    public Guest (String name, String checkinDate, String checkoutDate, double depAmt) 
    { 
     this.gstName = name; 
     this.checkIn = checkinDate; 
     this.checkOut = checkoutDate; 
     this.deposit = depAmt; 
    } 
}