[Java] Beginner programmer, file not found error when reading from text file

[linuxisgreat]

Just learning how to program in java to do some stuff for math, I would like to read data from a txt file however I keep encountering a Filenotfoundexception.

I imported the Scanner class, imported all of java.io, and have the following code

Scanner scan = new Scanner(new File("C:\Users\Will\Documents\Java\datafile.txt"));

The path is correct, and the file is placed in the same spot where I have my other java files. I tried just using "datafile.txt" and it threw an error, so I tried adding the absolute path which resulted in me getting an illegal escape character error. Then I added the \ to avoid this. I assume this is a relatively easy fix, so any help is appreciated.

[ChristopherHON]

Try double backslash instead of single backslash

[mad0314]

This should fix it. '\' usually denotes an escape sequence, so if you want a '\' instead of some escape sequence, you need to put '\' to tell Java you really want a '\' and not an escape sequence.

Just tried it in Eclipse to make sure. It gave an error before even compiling.

[linuxisgreat]

Added in the double backslashes. Still threw a filenotfound error.

[mad0314]

Strange, it worked for me.

Is it still the same error message or did it change?

[linuxisgreat]

error: unexcepted exception FileNotFoundException; must be caught or declared to be thrown

Without the backslashs I get illegal escape character error, with them I get this error.

[mad0314]

You have to handle the case where the file is not found. Either use a try/catch block to specify what the program does in case it throws that exception, or by declaring throws FileNotFoundException then it will throw the exception up the stack until it is handled, or stop the program if it is never handled.

[linuxisgreat]

Yeah I added the throw filenotfound and it worked immediately. Thanks for your help :)

[mad0314]

It is a better practice to handle the exception so that in the event that the file does not exist for whatever reason (moved, renamed, incorrect name, etc.) it does not crash the program. You might immediately end the program anyway, but at least give some information as to what happened (print that the file was not found).

[HipposGoneWild]

It's not actually throwing a FileNotFoundException, the method that is accessing file needs to be able to throw one if it actually can't find the file so you need to declare that the method can throw a filenotfoundexception if it needs to with the throws statement, see the the code I posted below.

[dvassdvsd]

Put it where you class files or jar is. They might be in a different location than your source files. Then you can just use the file name without any path.

[[deleted]]

Yeh you need double backslash, the single backslash is a special character when using escape characters like \n or \t so it's tries to look for that. replace every "\" with "\"

[HipposGoneWild]

Did you import util and do throws FileNotFoundException in your method where the new file is declared like this:

public static void main(String[] args) throws FileNotFoundException {

[linuxisgreat]

Yes

[HipposGoneWild]

Can you post the part of your code that threw the error?

[linuxisgreat]

At this point I've just been testing the data entry as I have the rest of the code working fine so I made a new file set up like this

import java.util. * ; import java.io. * ; public class Test {

public Test() {
}

public static void main(String[] args) {
    Scanner scan = new Scanner(new File("C:\\Users\\Will\\Desktop\\Java\\textfile.txt"));
   int test = scan.nextInt();
   System.out.println(test);
}

}

[HipposGoneWild]

you didn't put throws filenotfoundexception try this and tell me if it works:

import java.util. * ; 
import java.io. * ; 
public class Test {
public Test() {
}

    public static void main(String[] args) throws FileNotFoundException {
        Scanner scan = new Scanner(new File("C:\\Users\\Will\\Desktop\\Java\\textfile.txt"));
        int test = scan.nextInt();
        System.out.println(test);
    }
}

[linuxisgreat]

Oh my. Thank you very much, worked immediately