Java新手。 在while循环中使用扫描仪类时出错？

Question

So my first assignment involves making a simple question and answer program. The user asks a question, and I generate an answer. I've never done java before. Here is my input class:

//msg is the msg I output (answer to their question).
//Function returns inputStr which is the question the user asks.
public String getInput(String msg) {
    System.out.println(msg);
    Scanner theInput = new Scanner(System.in);
    String inputStr = theInput.nextLine(); //ERROR HERE ON 2nd ITERATION!
    theInput.close();
    if (inputStr.equals("exit")) {
        System.out.println("GoodBye!"); 
        System.exit(0);
    }
    return inputStr;
}

The function that calls this in the while loop is as follows:

    //inputSource is an object that has the getInput method. It is an argument for this function.
    String userQuestion = inputSource.getInput(firstLine);
    String initMsg = processMessage(userQuestion);
    while(!initMsg.equalsIgnoreCase("GoodBye")){
        userQuestion = inputSource.getInput(initMsg);
        //Doesn't get to here.
        initMsg = processMessage(userQuestion);
    }
    System.out.println(initMsg);

Error:

Exception in thread "main" java.util.NoSuchElementException: No line found
at java.util.Scanner.nextLine(Scanner.java:1516)

So basically, what happens is that it asks a question once, and then it gives back an answer once, but when it enters the while loop, it gets stuck at the indicated point. Little help. Thank you.

Answer 1

One thing that I noticed: you should probably not call close() on the scanner. You're closing the underlying input stream (standard input), according to the JavaDocs .