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Thread: Collecting Data from File

  1. #1
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    Default Collecting Data from File

    Hi guys,

    So I have a problem getting some Data from a particular file
    In this context I used API I/O and this is my chunk of code

    Scanner scanner = new Scanner(System.in);
    			System.out.print("Enter filename: ");
    			String file;
     
    			file = scanner.next();
    			//checks if the filename by the user exists
    			try{
    				dataFile = new Scanner(new File(file));
    			}
    			catch (FileNotFoundException e){
    				e.printStackTrace();
    			}  
    			scanner.close();

    The file is located right outside the package of all the code and program
    It always return an exception of the file not found and printing the stacktrace


    Thanks beforehand if anyone could help out


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    Default Re: Collecting Data from File

    Are you giving relative path of the file to be read?.

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    Default Re: Collecting Data from File

    Quote Originally Posted by dineshj83 View Post
    Are you giving relative path of the file to be read?.
    No,

    I want the program to work not only in my pc, and that's why I cannot use a specific path that only works in my Pc
    but the path itself is always right outside the package.

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    Default Re: Collecting Data from File

    Thats why i asked you to relative path which will work even if you package it and share it as jar to external world. Only in absolute path you will point to any of your drives in PC. Hope you got it now.

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    Default Re: Collecting Data from File

    I think relative path is used to specify the path has to be there, or can we give the path to link it for the directory outside the package?

    For example, if we put my package in the desktop, and the data also in the desktop
    how do you make a relative path that the data location is outside the package?

    Note: Sorry I'm still a newbie

    --- Update ---

    OH nevermind,
    I get it now,
    But could you give a simple example to create a relative path which in here i want it located outside my package?
    I've never using this kind of method so it probably would help me a lot to implement this way.

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    Default Re: Collecting Data from File

    For example if your code is in src/<package>/file and your file is in the same level as src then give only file name if its in a folder then it will be like foldername/filename. Hope you got it now.

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    Default Re: Collecting Data from File

    I know the concept now,
    but still confused how to implement it
    Could you / anyone explain how to implement the relative path inside my code?
    I've been trying to write it like this
    Scanner scanner = new Scanner(System.in);
    			System.out.print("Enter filename: ");
     
    			File file = new File(scanner.next());
     
     
    			// checks if the filename by the user exists
     
    			try {
     
    				dataFile = new Scanner(file);
    			} catch (FileNotFoundException e) {
    				e.printStackTrace();
    			}
     
    			scanner.close();
     
    		}
    so what's next?

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    Default Re: Collecting Data from File

    Your input on the console will be the filename and hence that has to be fed as relative path as explained.

  9. The Following User Says Thank You to dineshj83 For This Useful Post:

    blacksteel (November 29th, 2013)

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    Default Re: Collecting Data from File

    Quote Originally Posted by dineshj83 View Post
    Your input on the console will be the filename and hence that has to be fed as relative path as explained.
    What i was asking was, what do i need to write/add inside my code to make things(relative path) work

    Sorry for asking too much, because this is my first time using this kind of way

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    Default Re: Collecting Data from File

    Can you give examples of the file structure for the package and the location of the file? I'm not sure what you mean by the file being "right outside the package." Post code that demonstrates the problem, if possible.

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    Default Re: Collecting Data from File

    Quote Originally Posted by GregBrannon View Post
    Can you give examples of the file structure for the package and the location of the file? I'm not sure what you mean by the file being "right outside the package." Post code that demonstrates the problem, if possible.
    a.jpg
    I need to collect the data inside "DataFile"
    My program starts inside the PJ3.package(GasStationSimulator.java)

    My current code is the same as the first post

    What i want to happen, when I type the file name ( which is "DataFile" ) I can retrieve the data and use it for other method
    But with my current code, it always returning an exception of the file not found

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    Default Re: Collecting Data from File

    For me, the statement that would work in your case is:

    File = new File( "./src/PJ3/DataFile" );

    (notice the leading '.' or period.)

    So you'll need to "condition" the user's input with the appropriate relative file location and then use the resulting string instead of the user's input directly.

  14. The Following User Says Thank You to GregBrannon For This Useful Post:

    blacksteel (November 29th, 2013)

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    Default Re: Collecting Data from File

    Actually i figured out a very small mistake by accident
    Thanks to both of your help for the assistance

    Note for other people references : In fact, my code was working perfectly fine. If I compile and run in through cmd it works perfectly fine and read the file i wanted to open.
    Since i tried to run it using IDE (Eclipse) which create some default directory and few supporting files. It mislead the targeting directory that i want.(by adding another folder with the name "src")

    So in general for other people who face the same problem like I did, my tips will be, check your original directory by printing the current directory
    System.out.println(System.getProperty("user.dir");

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