您可以延迟bufferedReader以便它们在指定时间后才起作用吗？

Question

因此，我正在研究一个基本的数学游戏，并且我有一个与bufferedReaders有关的问题。在应用程序的第一部分中，输出显示一些介绍性消息，显示游戏的工作方式。之后游戏开始。

我唯一的问题是，在introductoryMessage（）方法期间（显然在startGame（）方法之前），用户可以在尚处于介绍阶段的状态下输入和提交项目，这可能会弄乱游戏。是否可以延迟bufferedReader，使其仅在运行startGame（）方法时运行？这是一些代码。

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.Random;
import java.util.concurrent.TimeUnit;

public class mainMathClass {

  public static void introductoryMessages() throws InterruptedException {


    System.out.println("Hello! This is an output based addition game.");

    TimeUnit.SECONDS.sleep(2);

    System.out.println("\nThe rules are simple. I will ask a math" +
      "\nquestion, and you will input the answer" +
      "\nunderneath the most recent question.");

    TimeUnit.SECONDS.sleep(3);

    System.out.println("\nHere is an example:");

    TimeUnit.SECONDS.sleep(2);

    System.out.println("\nWhat is 10/5?");

    TimeUnit.SECONDS.sleep(2);

    System.out.println("2");

    TimeUnit.SECONDS.sleep(2);

    System.out.println("\nIt is as simple as that. Each correct answer is " +
      "worth +1 point. Incorrect answers are worth -1 " +
      "points");

    TimeUnit.SECONDS.sleep(2);

    System.out.println("Here is question 1:");

    TimeUnit.SECONDS.sleep(3);
  }

  public static void startGame() throws IOException, InterruptedException {
    //Global variables. Do not move.
    BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
    String userInput;

    int correctAnswerCount = 0;
    int points = 0;
    int i;

    for (i = 1; i <= 10; i++) {
      /*The following variables must be declared in
       * in the for loop. If they are not, they cannot
       * change, meaning the for loop will not work
       * properly.
       */
      Random r = new Random();
      int low = 1;
      int high = 20;
      int a = r.nextInt(high - low) + low;
      int b = r.nextInt(high - low) + low;
      int problemAnswer = (a + b);
      /*Change the math symbol in problemAnswer
       *to change the way the game is played.
       *Be sure to change the string "+" to whatever
       *symbol you replaced the plus symbol with in problemAnswer
       */

      String aToString = Integer.toString(a);
      String bToString = Integer.toString(b);

      //Questions start here
      System.out.println("What is " + aToString + " + " + bToString + "?");

      userInput = br.readLine();
      int userInputToString = Integer.parseInt(userInput);

      //Check if userInputToString is equal to the math questions answer.
      //Display a certain message depending on if the users answer is correct.
      if (userInputToString == problemAnswer) { //Beginning of if-statement #1

        System.out.println("\nYou said " + userInputToString + ". That is correct!" +
          "\nYou earned 1 point!");
        points++;
        correctAnswerCount++;

        TimeUnit.SECONDS.sleep(2);
        System.out.println();

      } else {
        System.out.println("\nYou said " + userInputToString + ". That is incorrect." +
          "\nYou lost one point. :(");
        points--;

        TimeUnit.SECONDS.sleep(2);
        System.out.println();
      }

    }

    TimeUnit.SECONDS.sleep(2);
    System.out.println("You have " + correctAnswerCount + " questions answered correctly.");

    TimeUnit.SECONDS.sleep(2);
    System.out.println("\nYou have " + points + " points.");

  } //End of initializeProblem() method


  public static void main(String[] args) throws IOException, InterruptedException {

  }
}

此外，我一直在寻找如何使应用程序仅将数字作为输入，并在输入不是整数时显示错误并继续前进的方法。其中很多涉及try-catch块，我只是不知道将其放在哪里。如果有人在这里时有人可以帮助我，那就太好了。谢谢。