java - 为什么 Scanner.next() 不接受键盘输入按下？

Question

import java.util.InputMismatchException;
import java.util.Scanner;

class ClassB {

    public static void main(String[]args) throws Exception{
        ClassB b = new ClassB();
        b.getInput();
    }

    public void getInput() throws Exception {
        String label = null;
        int input;

        Scanner scan = new Scanner(System.in);
        for (input = 1; input != 4; input++){
            switch(input){
            case 1: label = "name";
            break;
            case 2: label = "password";
            break;
            case 3: label = "Room number";
            break;
            }
            System.out.println("Enter your " + label);
            scan.next();
            try{
                if (input == 1){
                    int name = scan.nextInt();
                    //residence.changeName(name);       
                }
                else if(input == 2){
                    String password = scan.next();
                }
                int rmNumber = scan.nextInt();
            }catch (IllegalArgumentException | InputMismatchException  me ){
                String type = "A string";
                String message = (input == 1 || input == 2) ? type : "An integer";
                input = 1;
            }
        }
    }
}

当我运行这段代码时，当按下计算机的回车键时，try-catch block 中的第一个scan.next()没有响应，因此无法输入后续的if()语句。文本字段中的光标仅换行，但输入永远不会被接受。我正在使用 netbean IDE

Answer 1

http://javatutorialhq.com/java/util/scanner-class-tutorial/

nextInt method does not read the last newline character of your input, and thus that newline is consumed in the next call to nextLine. To resolve this just use next instead of nextline but if you insist of using nextLine add another scan.nextLine() after nextInt. Take a look below snippet

-> 在 scan.nextInt() 之后添加 scan.nextLine()