Java String.split() - NumberFormatException

Question

So, here's the thing, I've got this code:

public static void main(String[] args) {
    try {
        FileInputStream fstream = new FileInputStream("test.txt");
        // Use DataInputStream to read binary NOT text.
        BufferedReader br = new BufferedReader(new InputStreamReader(fstream));
        String strLine = br.readLine();
        String[] split = strLine.split(" ");

        System.out.println(Integer.parseInt(split[0]));
        in.close();
    }
    catch (Exception e) {//Catch exception if any
        System.err.println("Error: " + e);
    }
}

let's say I have a file named test.txt , with just " 6 6 ". So, it reads first line and splits that line into two strings. The problem is that I can use Integer.parseInt for the split[1], but I can't use that method for split[0] ( System.out.println(split[0]) prints " 6 "), which outputs me an error of:

Error: java.lang.NumberFormatException: For input string: "6"

UPDATE: It might be problem of eclipse, because if I compile my .java files in terminal with javac, I don't get any exceptions!:))

UPDATE2: solved. something went wrong while saving with Kate. Don't know what, but gedit works better:D Thank you all.

Answer 1

Just try with: hexdump -C test.txt if you have linux, you can see the non-printable chars you have.

Also the trim() answer it's fine.

Answer 2

This problem at the start of the file is usually due to a BOM , which some software (mainly Notepad in fact) like to put at the start of Unicode files.

Open the file in a good text editor and configure it to save the files without the BOM.

If you can't change the file, skip the first char when reading it.

Answer 3

I'd try the following to rule out spurious/unexpected characters:

.. setup/read code in main method...
String[] split = strLine.split(" ");
for (String s : split) {
      System.out.println(String.format("[%s] => integer? %b", s, isInteger(s)));
}
... the rest of the main method....


private static boolean isInteger(String n) {
    try {
        Integer.parseInt(n);
    } catch(NumberFormatException e) {
        return false;
    }
    return true;
}

If you see anything inbetween the square brackets that isnt a number, or where the integer? returns false thats a likely the problem

Answer 4

如果您能够确定正在读取的文件的实际编码，则可以对其进行显式设置，以便将任何多余的字节正确地转换为字符。

new InputStreamReader(new FileInputStream(...), <encoding>)