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Thread: Can't find file (not sure the error)

  1. #1
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    Question Can't find file (not sure the error)

    Hello, I'm Taco. I am trying to create a java program that will allow users to open certain files (stored in a text file) by selecting something on a JList and clicking ok. When i program an application (the only other major experience in programming is in dos batch file), I try to make sure a certain element works before continuing, starting from the begging. So, first i tried to make sure java could read from the text file items.txt and store the names and path of a file

    this is the format the text in items.txt would be in (eventually i wat the user to be able press a button to create an item):

    <Name> (what the user sees on the list) <filepath> (the path that will be run)

    the code i used in the class is as follows:
    import java.awt.*;
    import java.io.*;
    import java.util.*;
    import javax.swing.*;
     
     
     
    public class b extends JFrame{
     
    	JList itemList;
    	Scanner x;
    	String items = "items.txt";
    	String[] itemNames;
    	String[] filepaths;
     
    	public b(){
    		super("Super Essentials");
    		setLayout(new FlowLayout());
     
    		getItemNamesAndPaths();
     
     
    	}
    	public void getItemNamesAndPaths(){
    		try{
    			x = new Scanner(new File(items));
    			int i = 0;
    			while(x.hasNext()){
    				itemNames[i] = x.next();
    				filepaths[i] = x.next();
    				i++;
    			}
    			x.close();
    			System.out.println(itemNames);
    		}
    		catch(Exception e){
    			System.out.println("error occured");
    		}
     
     
    		}
     
     
     
    	}

    i tried rearranging everything (except the first line) of the try block, but with everything in the try block that way it opens the window and gets rid of the exception stack, but there's still an error....

    it seems to me that the error is it cant find items.txt, even if change the path and such. or it could be that it cant input anything into itemNames[] or filepaths[].

    Heres the Exception stack (what was removed before i put the while loop, x.close(), and the println statement in the try block:

    Exception in thread "main" java.lang.NullPointerException
    at b.getItemNamesAndPaths(b.java:33)
    at b.<init>(b.java:20) (where the while loop was before)
    at a.main(a.java:6) (in a.java that line is b list = new b() i know fr a fact there's nothing wrong there, everything just needs to work)

    By the way, I use Eclipse.


  2. #2
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    Default Re: Can't find file (not sure the error)

    Which is line 33?
    Where is the rest of your code? If it is too long then create a SSCCE (google it).
    In the catch statement put e.printStackTrace() as this will give you more information than "error occured".
    Improving the world one idiot at a time!

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    Default Re: Can't find file (not sure the error)

    i kept the code as it is there. and put e.printStackTrace(); this is what was returned:

    java.io.FileNotFoundException: items.txt (The system cannot find the file specified)
    at java.io.FileInputStream.open(Native Method)
    at java.io.FileInputStream.<init>(Unknown Source)
    at java.util.Scanner.<init>(Unknown Source)
    at b.getItemNamesAndPaths(b.java:26)
    at b.<init>(b.java:20)
    at a.main(a.java:6)

    line 26 is x = new Scanner ...
    line 20 is getItemNamesAndPaths();
    and line 6 in a.java is the same as stated in the thread

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    Default Re: Can't find file (not sure the error)

    File not found is self evident. Your program cannot find a file called items.txt in the current working directory. Where is it?
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    Default Re: Can't find file (not sure the error)

    in the same directory as b.java

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    Default Re: Can't find file (not sure the error)

    System.out.println(System.getProperty("user.dir"));
    Add that as the first line in your program and it will display where it is looking for the file.
    Improving the world one idiot at a time!

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    Default Re: Can't find file (not sure the error)

    By the way you can just use a JFileChooser.
    Improving the world one idiot at a time!

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    Default Re: Can't find file (not sure the error)

    i was planning to use the JFileChooser for when the user wants to add an item. first an input dialog would appear for an alias they want, then the JFileChooser would ask them to find the file. both would be put into the text file.

    i put System.out.println(System.getProperty("user.dir")) ; in the catch statement (didn't seem to work outside the method, idk why) says its looking in C:\Users\(me)\workspace\(project name) ...

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    Default Re: Can't find file (not sure the error)

    is there any way to change where java is searching for the text file?

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    Default Re: Can't find file (not sure the error)

    You can either place the file in the location that the JVM is looking or you can include the full path.
    String filename = "C:/full/path/to/file/items.txt";
    Improving the world one idiot at a time!

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    Default Re: Can't find file (not sure the error)

    so know, String items = System.getProperty("user.dir") + "items.txt" in the exception stack i see at b.getItemNamesAndPaths(b.java:26) which is x = new Scanner(new File(items)); and im thinking that its the '(new File(items))' thats the problem, but i wouldnt know what else to put there...

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    Default Re: Can't find file (not sure the error)

    so now String items = System.getProperty("user.dir") + "items.txt"; and in the exception stack i see at b.getItemNamesAndPaths(b.java:26) which is the line that initiates x. i think maybe the error resides in (new File(item.txt)) however i dont knw what other parameters Scanner can take that'd be the same...

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    Default Re: Can't find file (not sure the error)

    oops... didnt mean t double post, didnt know there was another page

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    Default Re: Can't find file (not sure the error)

    Quote Originally Posted by KILL3RTACO View Post
    String items = System.getProperty("user.dir") + "items.txt"
    That is not going to work because that is not where the file is. Where in my previous reply did I suggest doing that?
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    Default Re: Can't find file (not sure the error)

    if i put the path to where the file is on my computer, then it wouldnt work if i distribute the program

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    Default Re: Can't find file (not sure the error)

    How are you launching the application?
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    Default Re: Can't find file (not sure the error)

    in Eclipse theres a green play button called run.

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    Default Re: Can't find file (not sure the error)

    Try running it from the command prompt or wrap all your files up in a jar file.
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    Default Re: Can't find file (not sure the error)

    Failed to load Main-Class manifest...

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    Default Re: Can't find file (not sure the error)

    Did you create a manifest file?
    Did the manifest file have the correct information?
    Did you include the manifest file in the jar file?
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    Default Re: Can't find file (not sure the error)

    when exporting, it doesnt show a .manifest to include... i didnt notice that last time.... in situations like this a usually start completely from scratch or close to it... however i end up typing the same thing or very similar... this'll be the second day where i have no idea what this problem is...

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    Default Re: Can't find file (not sure the error)

    Use the command line to create the jar file. Search for a jar tutorial. Or search for how your IDE can be configured to create the jar file.
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