Java 不会读取我的第二个进程

Question

这个问题已经有答案了:

Scanner issue when using nextLine after nextXXX [duplicate]

Scanner is skipping nextLine() after using next() or nextFoo()? (25 个回答)

已关闭 8 年前。

我现在正在学习Java，遇到一个问题。在我的场景中，我创建了一系列方法，并要求用户从其中选择一个。选择所需的方法后，将出现一条消息，要求输入字符串或整数。我的问题是在选择所需的方法后，它跳过了要求输入任何字符串/整数的第二阶段。希望您能理解我的问题。

这是我的简单代码:

import java.util.*;

import java.io.*;

public class MachineProblemChoser {

    static Scanner console = new Scanner(System.in);

    public static void main(String[] args) {

        int chosenProblem;

        System.out.println("Choose a problem you want to process");
        System.out.println("***********************************************");
        System.out.println("  1 -- Sum of digit");
        System.out.println("  2 -- Days of the month");
        System.out.println("  3 -- Largest number");
        System.out.println("  4 -- Fibonacci");
        System.out.println("  5 -- Palindrome");
        System.out.println(" -1 -- Exit");
        System.out.println("***********************************************");
        System.out.print(" Choose from(1-5) and -1 for exit: ");
        chosenProblem = console.nextInt();

        String numberSeries;
        int inputs;

        switch(chosenProblem) {

            case 1:

                //FROM THIS PART IT SKIPPED THE INPUT FROM THE USER
                System.out.println("SUM OF DIGIT");
                System.out.println("Input any integer separated by space:");
                numberSeries = console.nextLine();

                System.out.println("Count is: " + numberSeries.length());

            break;

            case 2:
                //machineProblemTwo();
            break;

            case 3:
                //machineProblemThree();
            break;

            case 4:
               // machineProblemFourth();
            break;

            case 5:
               //machineProblemFifth();
            break;

            case -1:
               exitProgram();
            break;

            default: 
               System.out.println(" Oops: Choose a valid number for the selection!");

        }

    }


    public static void machineProblemOne(String chosenNumber) {
        System.out.println("Chose number are: " + chosenNumber);  
    }

    public static int validateInput(int inputs) {

        return 0;
    }

    public static void exitProgram() {
        System.out.println(" Thanks for using the Machine Problem Choser! ");
    }

}

这是输出:

Choose a problem you want to process
***********************************************
  1 -- Sum of digit
  2 -- Days of the month
  3 -- Largest number
  4 -- Fibonacci
  5 -- Palindrome
 -1 -- Exit
***********************************************
 Choose from(1-5) and -1 for exit: 1
SUM OF DIGIT
Input any integer separated by space:         ---- From this it skipped
Count is: 0

Answer 1

scanner.nextInt();仅从输入中读取下一个整数。您需要清除剩余的回车符。试试这个:

...
System.out.println("***********************************************");
System.out.print(" Choose from(1-5) and -1 for exit: ");
chosenProblem = console.nextInt();
console.nextLine();//this clears out the rest of the input line

String numberSeries;
int inputs;
....