如果维数小于3，则没有中间矩阵，请尝试使用代码，

private static int[][] cropCenterPart(int[][] arr, int row, int col) {
    if (!(row > 2 && col > 2))
        return arr;
    int[][] resultArr = new int[row - 2][col - 2]; // as the first row,col and 
                                                   // last row,col is neglected
    for (int i = 1; i < row-1; i++) {
        System.arraycopy(arr[i], 1, resultArr[i - 1], 0, col - 1 - 1);
    }
    return resultArr;
}

在main函数（或从中调用的函数）中，如下打印

int resultArr[][] = cropCenterPart (arr, row, col);
for(int i = 0; i<row-2; i++) {   // here the row is the actual row size of arr
    System.out.println();
    for(int j=0; j<col-2; j++) {
        System.out.print(" " + resultArr[i][j]);
    }
}

答案是

public class A {

    public void extractBoundaries(int a[][],int rows,int cols){

        for (int i = 0; i < rows; i++) { 
            for (int j = 0; j < cols; j++) { 
                if (i == 0 || j == 0 || i == 3 || j == 3) 
                    System.out.print(a[i][j] + " "); 

                else
                    System.out.print("  "); 
            } 
            System.out.println(""); 
        }
        System.out.println("");
   }
    public void cropCenterPart(int a[][],int rows,int cols){

        for (int i = 0; i < rows; i++) { 
            for (int j = 0; j < cols; j++) { 
                if (i == 0 || j == 0 || i == 3 || j == 3) 
                  System.out.print("  ");
                else

                    System.out.print(a[i][j] + " ");
            } 
            System.out.println(""); 
        }
        System.out.println("");

    }
}