ArrayList对象（java）

Question

我坚持逻辑，需要我的项目帮助。
我有一个文本文件，其中有5个车辆名称。
然后，我要他们读入ArrayList，我没有使用它：

public static void main(String[] args) throws IOException 
{ 
    BufferedReader bTextFileVehicleNames = new BufferedReader(new FileReader("vehicles.txt")); 
    ArrayList<String> vechicleNamesArray = new ArrayList<String>(); 
    while((textFileLine = bTextFileVehicleNames.readLine()) != null) 
    { 
     vehicleNamesArray.add(textFileLine); 
    } 

现在，我需要在ArrayList创建每个项目（车名）一个对象，我没有用：

for(String s : vehicleNamesArray) 
{ 
    newVehicle = new Vehicle(s); 
    //I defined this Vehicle newVehicle = null; in the main class. My main is also in the same Vehicle.java file. 
} 

这些对象中的每一个都具有属性：power,angle, speed; 和行为：powerOn(),powerOff(), SpeedUp(),SlowDown()，等。我在Vehicle类定义。

现在，用户必须输入Vehicle name命令。然后我将它们分开并采取[0]这是车辆名称，并且必须首先检查它是否是ArrayList（源自txt文件）中的那些车辆名称中的一个，并且如果它然后必须将其引用到该特定对象我在上面创建。然后不得不采取在[1]，这是对应于对象的特定行为，它可以是powerOn，speedUp，等等等等命令..

for (int i=0; i< vehicleNamesArray.size(); i++) 
{ 
    if (vehicleNamesArray.get(i).matches(userVehicleName)) 
     //userVehicleName is the [0] vehicle name entered by user 
     //userVehicleCommand is the [1] command entered by user 
    { 
     switch (userVehicleCommand.toLowerCase()) 
     { 
     case "power on": 
      newVehicle.powerOn(); //calling that particular bahaviour of the object defined in Vehicle class. 
      System.out.println(newVehicle.getName()+" is powered ON."); 
      break; 
     ... 
    ... 

例如，让我们考虑有5辆车在txt（因此在ArrayList）命名为：奥迪，宝马，梅赛德斯，大众，保时捷。 问题是，无论我在车辆名称命令中输入，程序默认都采用最后一个元素，在这种情况下，保时捷在ArrayList。 也就是说，当我说“奥迪，powerON”时，它仍然打印出“保时捷开机。”。

我想我搞砸了链接用户输入的名称，以检查ArrayList，然后将其引用到该特定的对象。

Answer 1

请List还创建的对象：

List<Vehicle> vehicleList = new ArrayList<>; 
for(String s : vehicleNamesArray) 
{ 
    newVehicle = new Vehicle(s); 
    vehicleList.add(newVehicle); 
    //I defined this Vehicle newVehicle = null; in the main class. My main is also in the same Vehicle.java file. 
} 

在你的第二个 for loop检索车辆对象，并对其进行更新

然后：

for (int i=0; i< vehicleNamesArray.size(); i++) 
{ 
    if (vehicleNamesArray.get(i).matches(userVehicleName)) 
     //userVehicleName is the [0] vehicle name entered by user 
     //userVehicleCommand is the [1] command entered by user 
    { 
     switch (userVehicleCommand.toLowerCase()) 
      { 
       case "power on": 

       vehicleList.get(i).powerOn(); //calling that particular bahaviour of the object defined in Vehicle class. 
       System.out.println(vehicleList.get(i).getName()+" is powered ON."); 
       break; 
... 
... 

Answer 2

你可能想尝试存储车辆在HashMap什么：

HashMap<String, Vehicle> vehicles = new HashMap<String, Vehicles>(); 

for(String s : vehicleNamesArray) 
{ 
    vehicles.put(s, new Vehicle(s)); 
} 

//Access the vehicle from user input 

Vehicle currentVehicle = vehicles.get(userVehicleName); 

switch (userVehicleCommand.toLowerCase()) 
{ 
    case "power on": 
    currentVehicle.powerOn(); //calling that particular bahaviour of the object defined in Vehicle class. 
    System.out.println(currentVehicle.getName()+" is powered ON."); 
    break; 
    //etc... 
} 

一个HashMap可以用来存储key,value对你的情况key=carnamevalue=Vehicle object。这将使您可以轻松地根据用户输入返回并选择想要的汽车。目前还没有你的存储您Vehicle对象，你只能保存最后一个......