在 do While 循环中出现 "Exception in thread "main" java.util.InputMismatchException" 错误

Question

import java.util.Random;
import java.util.Scanner;


public class Jogo {
 Scanner scanner = new Scanner(System.in);
int tipoJogo;
int turno;
Barco[] jfA,jfB;
Random random = new Random();

public Jogo(Barco[]fA, Barco[]fB, int tamanhomax, int tj)
{
    for(int i =0;i<tamanhomax;i++)
    {
        fA[i]=fB[i]=null;
    }

    jfA = fA;
    jfB = fB;
    tipoJogo=tj;
}



//public Barco[] getFrota() {
//  return frota;
//}
int linhaAC = random.nextInt(7);
int colunaAC = random.nextInt(7);
int orientação = random.nextInt(1);



public Jogo(int TipoJogo){
    TipoJogo = tipoJogo;
}
public  void manual1(){
    System.out.println("Jogador A");
    System.out.println("Insira as coordenadas do Aircraft Carrier e a sua orientação(0 horizontal, 1 vertical):");
    //linhaAC = scanner.nextInt();
    //colunaAC = scanner.nextInt();

    String op= scanner.nextLine();

    int linhaAC = (int) Character.toUpperCase(op.charAt(0))-'A'; //vai buscar o primeiro caracter da String op e transforma do A ao I em interiros 0 a 8
    int colunaAC = (int) op.charAt(1)-'1';
    int orientação = scanner.nextInt();
    System.out.println(linhaAC +"  -  " + colunaAC);


    do{

        System.out.println("Fora do tabuleiro");
        System.out.println("Insira de novo as coordenadas do Aircraft Carrier:  ");
        linhaAC= (int) Character.toUpperCase(op.charAt(0))-'A';
        colunaAC = (int) op.charAt(1)-'1';
        orientação = scanner.nextInt();

    }while((colunaAC > 4 && orientação == 0)|| (linhaAC > 'D' && orientação == 1));

好的，我收到以下错误代码：

Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Scanner.java:864)
at java.util.Scanner.next(Scanner.java:1485)
at java.util.Scanner.nextInt(Scanner.java:2117)
at java.util.Scanner.nextInt(Scanner.java:2076)
at Jogo.manual1(Jogo.java:147)
at Main.start(Main.java:134)
at Main.main(Main.java:26)

当我尝试在 do while 循环中为变量 LinhaAC 和 ColunaAC 设置新值时会发生这种情况。

基本上，如果我将 LinhaAC 设置为大于 'D' 或将 ColunaAC 设置为大于 4，它会启动 Do while 循环，我要求用户向这些变量插入新值。

因此，当我尝试设置新值时，在插入 LinhaAC 和 ColunaAC 后按回车键，以便为 "orientação" 选择新值，这会触发错误。

它只发生在 do while 组中。在我第一次插入值时，它没有给出任何错误。

编辑：即使我使用我第一次选择的相同值也会发生这种情况。它不像我在 scanner.next() 上插入一个 int；

Answer 1

您的代码没有错误。原因是您得到 InputMismatchException 因为您的输入与变量类型不匹配。

您正在接受三个输入，它们的类型应该匹配。

这就是出现这些错误消息的原因：

at java.util.Scanner.next(Scanner.java:1485)
at java.util.Scanner.nextInt(Scanner.java:2117)
at java.util.Scanner.nextInt(Scanner.java:2076)

例如：

orientação = scanner.nextInt();

这一行需要整数值，但如果你添加 String 它会给你 InputMismatchException

解决方案：

为避免这种情况，您可以处理输入类型，如果它不是整数，您可以通过 try-catch block 显示正确的消息。

try{
    orientação = scanner.nextInt();
}catch(InputMismatchException e){
    System.out.println("Enter only integer");
}

或者您可以像这样打印错误消息，

//...
catch(InputMismatchException e){
    System.out.println(e);
}

同样对从键盘获得的每个输入执行此操作。这将避免错误消息并使您的程序更易于处理。

详细了解 exception handling。

Answer 2

终于修好了

public  void manual1(){
    System.out.println("Jogador A");
    System.out.println("Insira as coordenadas do Aircraft Carrier e a sua 
     orientação(0 horizontal, 1 vertical):");
    //linhaAC = scanner.nextInt();
    //colunaAC = scanner.nextInt();

    String op= scanner.next();

    int linhaAC = (int) Character.toUpperCase(op.charAt(0))-'A';
    int colunaAC = (int) op.charAt(1)-'1';
    int orientação = scanner.nextInt();
    System.out.println(linhaAC +"  -  " + colunaAC);


    while((colunaAC >= 4 && orientação == 0) || (linhaAC >= 4 && orientação == 1)){

        System.out.println("Fora do tabuleiro");
        System.out.println("Insira de novo as coordenadas do Aircraft Carrier:  ");
        op= scanner.next();
        linhaAC=(int)Character.toUpperCase(op.charAt(0))-'A';
        colunaAC = (int) op.charAt(1)-'1';
        orientação = scanner.nextInt();
        System.out.println(linhaAC +"  -  " + colunaAC);


    }

在 do While 循环中出现 "Exception in thread "main" java.util.InputMismatchException" 错误

Getting an "Exception in thread "main" java.util.InputMismatchException" error inside a do While Loop

java

java.util.scanner

inputmismatchexception