如何确定我从文件中读取的内容？ 爪哇

Question

So I want to read a file, that contains numbers separated by spaces. For example, the file "try.txt" content is:

1 2 3
4 5 6
7 8 9

I know how to read this numbers and store them in an array with a Scanner, and two nested for loops.Ignore any possible sintax errors here. It would look like:

int i,j;
Scanner sc
for(i=0;i<array.length;i++){
   for(j=0;j<array[i].length;j++){
      array[i][j]=sc.nextInt();
   }
}

So my question is, how can I check that what I am reading is actually an integer? What happens if nextInt() finds a letter, or another ASCII symbol?

Thank you.

Answer 1

Try this code

if (obj instanceof Integer) 
{
    // is a integer
} 
else 
{
   // is not
}

Answer 2

At the end, I solved this problem using InputMissmatchException. Here is an example:

Scanner sc = new Scanner(System.in);
try{
    int a = sc.nextInt();
}catch(java.util.InputMismatchException e) {
        System.out.println("Invalid file content");
}