Question

在这个程序中，我需要用户在另一个数组类中输入yes / no。但是字符串输入不起作用。我用一个整数尝试了它，但它没有用字符串。

package airliner.boarding.system;

import java.util.Scanner;

公共类BoardPlane {

private boolean firstClass[];
private boolean economyClass[];
private static Scanner input ; 


public BoardPlane(){
    firstClass = new boolean[5];
    economyClass = new boolean[5];
    input = new Scanner(System.in);
}

public void setSeat(int seatClass){
    if(seatClass == 1){
        fillFirstClass();
    }else if(seatClass == 2){
        fillEconomyClass();
    }
}

private void fillEconomyClass(){
    for(int counter = 0; counter < economyClass.length; counter++){
        if(economyClass[counter] == false){
            economyClass[counter] = true;
            System.out.println("Your seat number is "+(++counter)+" in the economy class");
            break;
        }else if(counter == 4){
            System.out.println("Economy class is filled. is it okay to place you in first class? YES/NO: ");
            String choice = input.nextLine();
            choice = choice.toUpperCase();
            if(choice.equals("YES")){
                 switchSeats(2);
            }else{
                System.out.println("Next flight leaves in three hours.");
            }
        }
    }
}

private void fillFirstClass(){
    for(int counter = 0; counter < firstClass.length; counter++){
        if(firstClass[counter] == false){
            firstClass[counter] = true;
            System.out.println("Your seat number is "+(++counter)+" in the first class");
            break;
        }else if(counter == 4 ){
            System.out.println("First class is filled. is it okay to place you in economy class? YES/NO:");
            String choice = input.nextLine();
            choice = choice.toUpperCase();
            if(choice.equals("YES")){
                 switchSeats(1);
            }else{
                System.out.println("Next flight leaves in three hours.");
            }

        }
    }
}

private void switchSeats(int i){
    if(i == 1){
        for(int counter = 0; counter < economyClass.length; counter++){
            if(economyClass[counter] == false){
                economyClass[counter] = true;
                System.out.println("Your seat number is "+(++counter)+" in the economy class");
                break;
            }else if(counter == 4){
                System.out.println("Economy class is filled");
            }
        }
    }else if(i == 2){
        for(int counter = 0; counter < firstClass.length; counter++){
            if(firstClass[counter] == false){
                firstClass[counter] = true;
                System.out.println("Your seat number is "+(++counter)+" in the first class");
                break;
            }else if(counter == 4){
                System.out.println("First class is filled");
            }
        }
    }
}

public static void main(String [] args){
    BoardPlane plane = new BoardPlane();
    for(int i = 0; i <= 10; i++){
        System.out.println("Enter 1 for first class and 2 for economy class: ");
        int userInput = input.nextInt();
        plane.setSeat(userInput);
    }
}

}

Answer 1

当你致电nextInt()时，它只会读取数字，而不会读取该行的其余部分，而不是您输入的新行。

这意味着如果您稍后致电nextLine()，它会读取该号码之后的内容，即很可能没有。

一个简单的解决方法是忽略数字后面的其余部分。

int userInput = input.nextInt();
input.nextLine(); // ignore the rest of the line.

Answer 2

我有同样的问题，当你使用扫描仪，并把消息与System.out.println（），newLine无法正常工作。我不知道为什么？！当您在控制台中输出消息后输入= new Scanner（System.in）时，它的工作正常。

但是你可以制作一个方法来提供用户输入，并且在这个方法中制作一个像这样的重新扫描器：

publis static String getUserInput（String message）{

的System.out.println（消息）;

input = new Scanner（System.in）;

返回input.nextLine（）;

}

程序不会提示输入字符串，但会提示其他数据类型

2 个答案: