我正在开发一个基于文本的冒险游戏，需要一些帮助来处理getUserRoomChoice（）函数上的IndexOutOfBounds异常。我在菜单上的索引为3，因此当用户输入数字> 3时，它将引发该异常。我尝试在提示用户“选择数字”的行上使用try-catch，但没有捕获它。
这是我的主要班级：
import java.util.Scanner;
public class Game {
private static Room library, throne, study, kitchen;
private static Room currentLocation;
public static void main(String[] args) {
Scanner input = new Scanner(System.in);
initialSetupGame();
String reply;
do {
printNextRooms();
int nextRoomIndex = getUserRoomChoice();
Room nextRoom = getNextRoom(nextRoomIndex);
updateRoom(nextRoom);
System.out.print("Would you like to continue? Yes/No: ");
reply = input.nextLine().toLowerCase();
} while ('y' == reply.charAt(0));
goodbye();
}
public static void initialSetupGame() {
// Instantiate room objects of type Room
library = new Room("Library");
throne = new Room("Throne");
study = new Room("Study");
kitchen = new Room("Kitchen");
// Connect the objects to each other
library.addConnectedRoom(throne);
library.addConnectedRoom(study);
library.addConnectedRoom(kitchen);
throne.addConnectedRoom(library);
throne.addConnectedRoom(study);
throne.addConnectedRoom(kitchen);
study.addConnectedRoom(library);
study.addConnectedRoom(throne);
study.addConnectedRoom(kitchen);
kitchen.addConnectedRoom(library);
kitchen.addConnectedRoom(study);
kitchen.addConnectedRoom(throne);
// Welcome message
System.out.println("Welcome to Aether Paradise, "
+ "a game where you can explore"
+ " the the majestic hidden rooms of Aether.");
// Prompt user for a name
Scanner input = new Scanner(System.in);
System.out.print("\nBefore we begin, what is your name? ");
String playerName = input.nextLine();
System.out.print("\n" + playerName +"? Ah yes. The Grand Warden told us"
+ " to expect you. Nice to meet you, " + playerName + "."
+ "\nMy name is King, a member of the Guardian Aethelorian 12"
+ " who protect the sacred rooms of Aether."
+ "\nAs you hold the Warden's signet ring, you have permission"
+ " to enter.\n\nAre you ready to enter? ");
String response = input.nextLine().toLowerCase();
if ('n' == response.charAt(0)) {
System.out.println("Very well then. Goodbye.");
System.exit(0);
}
if ('y' == response.charAt(0)) {
System.out.println("\nA shimmering blue portal appeared! You leap "
+ "inside it and your consciousness slowly fades...");
}
else {
System.out.println("Invalid input. Please try again.");
System.exit(1);
}
// Set the player to start in the library
currentLocation = library;
System.out.print("\nYou have spawned at the library.");
System.out.println(currentLocation.getDescription());
}
public static void printNextRooms() {
// Lists room objects as menu items
System.out.println("Where would you like to go next?");
currentLocation.printListOfNamesOfConnectedRooms();
}
// How to handle the exception when input > index?
public static int getUserRoomChoice() {
Scanner input = new Scanner(System.in);
System.out.print("(Select a number): ");
int choice = input.nextInt();
return choice - 1;
}
public static Room getNextRoom(int index) {
return currentLocation.getConnectedRoom(index);
}
public static void updateRoom(Room newRoom) {
currentLocation = newRoom;
System.out.println(currentLocation.getDescription());
}
public static void goodbye() {
System.out.println("You walk back to the spawn point and jump into"
+ "the portal... \n\nThank you for exploring the hidden rooms "
+ "of Aether Paradise. Until next time.");
}
}
房间等级
import java.util.ArrayList;
public class Room {
// Instance variables
private String name;
private String description;
private ArrayList<Room> connectedRooms;
// Overloaded Constructor
public Room(String roomName) {
this.name = roomName;
this.description = "";
connectedRooms = new ArrayList<>();
}
// Overloaded Constructor
public Room(String roomName, String roomDescription) {
this.name = roomName;
this.description = roomDescription;
connectedRooms = new ArrayList<>();
}
// Get room name
public String getName() {
return name;
}
// Get room description
public String getDescription() {
return description;
}
// Add connected room to the array list
public void addConnectedRoom(Room connectedRoom) {
connectedRooms.add(connectedRoom);
}
// Get the connected room from the linked array
public Room getConnectedRoom(int index) {
if (index > connectedRooms.size()) {
try {
return connectedRooms.get(index);
} catch (Exception ex) {
System.out.println(ex.toString());
}
}
return connectedRooms.get(index);
}
// Get the number of rooms
public int getNumberOfConnectedRooms() {
return connectedRooms.size();
}
// Print the connected rooms to the console
public void printListOfNamesOfConnectedRooms() {
for(int index = 0; index < connectedRooms.size(); index++) {
Room r = connectedRooms.get(index);
String n = r.getName();
System.out.println((index + 1) + ". " + n);
}
}
}
您必须仔细查看这段代码，尝试在其中访问列表（或数组）。那是引发异常的部分，而不是用户输入异常的部分。您必须在此处检查给定的索引是否大于列表的大小。
if( index >= list.size()) {
// handle error / print message for user
} else {
// continue normaly
}
在您的情况下，可能在类getConnectedRoom(int index)中的方法Room中。
特定部分的try / catch块在哪里？无论如何，您可以为其使用IndexOutOfBound或Custome Exception。
1。创建自定义异常类
class RoomeNotFoundException extends RuntimeException
{
public RoomeNotFoundException(String msg)
{
super(msg);
}
}
为特定部分添加try / catch块
public class Game
{
do {
printNextRooms();
int nextRoomIndex = getUserRoomChoice();
if(nextRoomeIndex>3)
{
throw new RoomNotFoundException("No Rooms Available");
}else{
Room nextRoom = getNextRoom(nextRoomIndex);
updateRoom(nextRoom);
System.out.print("Would you like to continue? Yes/No: ");
reply = input.nextLine().toLowerCase();
}
} while ('y' == reply.charAt(0));
}
或者您可以使用IndexOutOfBoundException代替RoomNotFoundException
您必须在getNextRoom()的函数调用中使用try-catch。因为getNextRoom(nextRoomIndex)导致了异常。您必须将这两个语句放在try块中。
将此更改为
Room nextRoom = getNextRoom(nextRoomIndex);
updateRoom(nextRoom);
此
try{
Room nextRoom = getNextRoom(nextRoomIndex);
updateRoom(nextRoom);
} catch(Exception e){
System.out.println("print something");
}