java - 程序不提示输入字符串，但提示其他数据类型

Question

在这个程序中，我需要用户输入是/否以在另一个数组类中设置。但是字符串输入不起作用。我用整数尝试过，它可以工作，但不能用字符串。

包airliner.boarding.system;

导入java.util.Scanner;

公共(public)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

当您调用 nextInt() 时，它只会读取数字，不会读取该行的其余部分，也不会读取您键入的新行。

这意味着如果您稍后调用nextLine()，它将读取该数字后面的内容，即很可能什么也没有。

一个简单的解决方法是忽略数字后面的行的其余部分。

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