Java輸入條件

Question

我有兩個類。我試圖讓：客戶

-The電話號碼不是空白的，是10個字符
否則重新進入

-The車輛數爲1和10（1和10包括）之間
否則重新輸入

-The燃料箱的數目只能是（2，4，8，10，15，20）
否則重新輸入

我不知道如何讓電話號碼= 10位數字。車輛不止一次輸入（1-10）以外的值後，跳到油箱的數量。輸入除（2,4,8,10,15,20）以外的值後相同。我究竟做錯了什麼？幫助表示讚賞。謝謝。代碼

VehicleApp.Java段

public static void main(String[] args) { 
String firstname = JOptionPane.showInputDialog("Enter your first name"); 
while (firstname.equals("")){ 
firstname = JOptionPane.showInputDialog("Enter your first name"); 
} 

String lastname = JOptionPane.showInputDialog("Enter your last name"); 
while (lastname.equals("")){ 
lastname = JOptionPane.showInputDialog("Enter your last name"); 
} 

String phone = JOptionPane.showInputDialog("Enter your phone"); 
while (phone.equals("")){ 
phone = JOptionPane.showInputDialog("Enter your phone"); 
} 

int nbrVehicles = Integer.parseInt(JOptionPane.showInputDialog("Enter number of vehicles")); 
if (nbrVehicles < 1 || nbrVehicles > 10){ 
JOptionPane.showInputDialog("Enter number of vehicles"); 
} 

int nbrTanks = Integer.parseInt(JOptionPane.showInputDialog("Enter number of tanks")); 
if (nbrTanks != 2 || nbrTanks != 4 || nbrTanks != 8 || nbrTanks != 10 || nbrTanks != 15 || nbrTanks != 200){ 
JOptionPane.showInputDialog("Enter number of tanks"); 
} 

VehicleFactory vehicleObject = new VehicleFactory(); 
vehicleObject.HayloFactory(firstname, lastname, phone, nbrVehicles, nbrTanks); 
vehicleObject.calcFuelTankCost(); 
vehicleObject.calcManufacturingCost(); 
vehicleObject.calcSubtotal(); 
vehicleObject.calcTax(); 
vehicleObject.calcTotal(); 
vehicleObject.getSummary();    
} 
} 

Answer 1

你可以嘗試while：

int nbrVehicles = Integer.parseInt(JOptionPane.showInputDialog("Enter number of vehicles")); 
while (nbrVehicles < 1 || nbrVehicles > 10) 
    nbrVehicles = Integer.parseInt(JOptionPane.showInputDialog("Enter number of vehicles")); 
}