Java中的Try｛｝Catch｛}在Try{｝之前执行Catch

Question

我遇到了一个无法解决的问题。我正在运行下面的代码，并为此输入：

*输入单元格：XXOO_OX

|X X||O O||O X|

输入坐标：您应该输入数字输入坐标：一你应该输入数字！输入坐标：ont three你应该输入数字！输入坐标：1 3

|X X||O O||O X|

进程结束，退出代码为0*

在运行它之后，我在输入坐标之前得到了catch消息。为什么？我应该更改什么？

扫描仪扫描仪=新扫描仪(System.in(；String[][]tictactoe=新String[3][3]；

//init method
System.out.print("Enter cells: ");
String s = scanner.next();

String a = s.substring(0, 1);
tictactoe[0][0] = a;
String b = s.substring(1, 2);
tictactoe[0][1] = b;
String c = s.substring(2, 3);
tictactoe[0][2] = c;
String d = s.substring(3, 4);
tictactoe[1][0] = d;
String e = s.substring(4, 5);
tictactoe[1][1] = e;
String f = s.substring(5, 6);
tictactoe[1][2] = f;
String g = s.substring(6, 7);
tictactoe[2][0] = g;
String h = s.substring(7, 8);
tictactoe[2][1] = h;
String i = s.substring(8, 9);
tictactoe[2][2] = i;
for (int n = 0; n < 3; n++) {
for (int m = 0; m < 3; m++) {
String cuv = tictactoe[n][m];
if (cuv.equals("_")) {
tictactoe[n][m] =" ";
}
}
}
System.out.println("---------");
System.out.println("| " + tictactoe[0][0] + " " + tictactoe[0][1] + " " + tictactoe[0][2] + " |");
System.out.println("| " + tictactoe[1][0] + " " + tictactoe[1][1] + " " + tictactoe[1][2] + " |");
System.out.println("| " + tictactoe[2][0] + " " + tictactoe[2][1] + " " + tictactoe[2][2] + " |");
System.out.println("---------");
String player1 = "X";
String letter;
boolean correctCoordinate=false;
while (!correctCoordinate){
System.out.print("Enter the coordinates:");
String input=scanner.nextLine();
String [] pieces = input.trim().split("\s+");
int x;
int y;
try {
x = Integer.parseInt(pieces[0]);
y = Integer.parseInt(pieces[1]);
letter = tictactoe[3-y][x-1];
if (letter.equals("X") || letter.equals("O")) {
System.out.println("This cell is occupied! Choose another one!");
} else {
tictactoe[3-y][x-1]=player1;
System.out.println("---------");
System.out.println("| " + tictactoe[0][0] + " " + tictactoe[0][1] + " " + tictactoe[0][2] + " |");
System.out.println("| " + tictactoe[1][0] + " " + tictactoe[1][1] + " " + tictactoe[1][2] + " |");
System.out.println("| " + tictactoe[2][0] + " " + tictactoe[2][1] + " " + tictactoe[2][2] + " |");
System.out.println("---------");
correctCoordinate=true;
}
}catch (NumberFormatException err1) {
System.out.println("You should enter numbers!");
}catch (ArrayIndexOutOfBoundsException err2){
System.out.println("Coordinates should be from 1 to 3!");
}
}

谢谢，Florin

Answer 1

调试代码的最佳方法是堆栈跟踪。

尝试添加

catch (NumberFormatException err1) {
err1.printStackTrace();
System.out.println("You should enter numbers!");
}catch (ArrayIndexOutOfBoundsException err2){
err2.printStackTrace();
System.out.println("Coordinates should be from 1 to 3!");
}

这样你就可以追踪你的问题。

希望对你有所帮助。

祝你今天愉快：(