从.txt文件中读取字符串，然后将其转换为整数

Question

I am attempting to read some data from a text file, this goes in the format:

10
1
s
q

here is the code:

public static void main(String[] args) {

        String line = null;

        int[] b= new int[10];
        int i = 0;

        try {
            BufferedReader bf = new BufferedReader(new FileReader("C:\\myFile.txt"));

            while ((line = bf.readLine()) != null) {

                b[i] = Integer.parseInt(line);
                i++;

            }

        } catch (IOException e) {
            System.out.println(e.getMessage());

        }
}

this b[i] = Integer.parseInt(line); easily reads first line from the file that is '10' and same goes for the second line that is '1' but for the third line 's' compiler gives me following error

Exception in thread "main" java.lang.NumberFormatException: For input string: "s"
    at java.lang.NumberFormatException.forInputString(NumberFormatException.java:65)
    at java.lang.Integer.parseInt(Integer.java:580)
    at java.lang.Integer.parseInt(Integer.java:615)
    at test.Main.main(Main.java:41)

I need to convert String 's' and 'H' to an integer value and then store into my array b of integer type.

Answer 1

Check first that if string contains alphabet or numbers

if(line.matches("[a-zA-Z]+"))
    int a=(int)line.charAt(0);

else if(line.matches("[0-9]+"))
    int a=Integer.parseInt(line);

Answer 2

This should work if you have only one character:

char c = b[i].charAt(0);
int x = c - 48;

Answer 3

you can convert your text file into byte array then convert this array into int array

public static void Do()
{

    try {
        InputStream in;
        in = new FileInputStream("a.txt");
        byte[] array = new byte[in.available()];
        in.read(array);
        int[] array2 = new int[array.length];
        for (int i = 0 ; i<array.length ; i++)
        {
            array2[i] = array[i];
            System.out.println(array2[i]+"");
        }

    } catch (FileNotFoundException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }


}

and the output will be like this

13 10 99 13 10 100 13 10 100 102 104 102 103 104 103 102 104

its depending in your text file characters . data in a.txt is (abcd dfhfghgfh )

but for me ,,, I will give every char an integer value then use if statment to convert char to int