如何修复java.lang.arrayindexoutofboundsexception:0？

Question

我是新手java.任何人都可以帮我解决错误arrayindexoutofboundsexception.

public class Minesweeper { 
   public static void main(String[] args) { 

      int M = Integer.parseInt(args[0]);
      int N = Integer.parseInt(args[1]);
      double p = Double.parseDouble(args[2]);

      // game grid is [1..M][1..N], border is used to handle boundary cases
      boolean[][] bombs = new boolean[M+2][N+2];
      for (int i = 1; i <= M; i++)
         for (int j = 1; j <= N; j++)
            bombs[i][j] = (Math.random() < p);

      // print game
      for (int i = 1; i <= M; i++) {
         for (int j = 1; j <= N; j++)
            if (bombs[i][j]) System.out.print("* ");
            else             System.out.print(". ");
         System.out.println();
      }

      // sol[i][j] = # bombs adjacent to cell (i, j)
      int[][] sol = new int[M+2][N+2];
      for (int i = 1; i <= M; i++)
         for (int j = 1; j <= N; j++)
            // (ii, jj) indexes neighboring cells
            for (int ii = i - 1; ii <= i + 1; ii++)
               for (int jj = j - 1; jj <= j + 1; jj++)
                  if (bombs[ii][jj]) sol[i][j]++;

      // print solution
      System.out.println();
      for (int i = 1; i <= M; i++) {
         for (int j = 1; j <= N; j++)
            if (bombs[i][j]) System.out.print("* ");
            else             System.out.print(sol[i][j] + " ");
         System.out.println();
      }

   }
}

这是例外:

Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 0 at Minesweeper.main(Minesweeper.java:5) 

Answer 1

可能有两件事,因为它表示索引0(参见第一个案例):

1. 您没有将参数传递给主类.

2. 数组索引始终从0开始而不是1.因此您可能需要更改:

   • 你的循环从0开始并检查i <M或N.
   • 您使用数组索引作为i - 1而不是i.

你得到ArrayIndexOutOfBoundException的原因是假设你有一个数组中的2个元素.它将如下:

a[0] = 1;
a[1] = 2;

当你使用i = 1循环时; 我<= 2你正在访问:

a[1] - which is perfect
a[2] - which was not expected?

Answer 2

args在访问元素之前,您必须检查数组的长度.因为您必须访问数组中的第二个元素,所以长度应至少为3.您必须检查如下所示

if(args.length > 2) {
  //wrap all code here
}