Jar can't access txt files

Question

I'm pretty new to Java and I'm facing a problem that I can't find a solution for. I have written a program that reads and writes to a txt file. When I run it in NetBeans it seems to be working fine, but when I try to run the JAR file, it seems as if the program can't access the txt file.

I created the file using the following code :

File data = new File("src/data.txt");

Could the reason why it won't work be in the creation of the file? And if not what could it be?

EDIT: The text file is being modified as program advances, if I use the inputstream I won't be able to write to or change the txt file, should I change the way on which I'm managing my data? ( txt files) or is there a way for the jar to still have access to the Txt file?

Reimeus · Answer 1 · 2013-09-24T16:16:51.580

7

This statement

File data = new File("src/data.txt");

relys on the file being present in the file system. You need to read the file as a resource so that the JAR file can be run independently of the text file

InputStream input = getClass().getResourceAsStream("/path/to/data.txt");

Edit:

I suggest using the strategy of storing the the text file in as a "default", then when changes are required, write a new file under "user.home". Check the existence of the modified file before reading any data.

edited Sep 24 '13 at 16:16

answered Sep 24 '13 at 14:18

Reimeus

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Just out of interest: are you able to explain the difference between your solution and @shamimz's answer below? I can't quite work it out. – devrobf Sep 24 '13 at 14:31
1

Also I just realised OP says that he is writing to the file as well; so surely his problem is more than just this? It sounds like he really does want to read/write to a file on disk, and his problem is the use of the `src` directory which probably doesn't exist... – devrobf Sep 24 '13 at 14:33
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@jazzbassrob In relation to your first question there are some subtle differences between the 2 such as this approacj requires the absolute path to be specified, i.e. leading `/` needed. See this [answer](http://stackoverflow.com/questions/676250/different-ways-of-loading-a-file-as-an-inputstream) – Reimeus Sep 24 '13 at 14:36
@ShaharKazaz Only use the text file JAR file as a "default" input. See the update – Reimeus Sep 24 '13 at 16:25

score 5 · Accepted Answer · edited Feb 11 '18 at 08:38

5

Method 1: Where you are creating jar and running the program there is no such folder called "src" under the jar directory. You should create a folder called "src" in same directory of jar location. This will allow file write operation.

Method 2: If you want to keep the txt file inside the jar then you can use:

InputStream in = this.getClass().getClassLoader()
                            .getResourceAsStream("your package path/data.txt");

A complete example:

package com.file.loader;

public class Main {
    public static void main(String[] args) throws IOException {
    InputStream in = Main.class.getClassLoader().getResourceAsStream(
            "com/file/loader/data.txt");
    }
}

edited Feb 11 '18 at 08:38

Robbie III

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answered Sep 24 '13 at 14:19

Shamim Ahmmed

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I have tried placing the files in a different package but that doesn't work – Shahar Kazaz Sep 24 '13 at 15:11
please post your package name and the path you are providing – Shamim Ahmmed Sep 24 '13 at 15:14
Package name : storageData and the file name is data.txt. But look at what I've edited. I want writing to the file, not only reading from it – Shahar Kazaz Sep 24 '13 at 15:31
1

@ShaharKazaz, See my updated answer, I think this might help you understand better. – Shamim Ahmmed Sep 24 '13 at 15:32
Correct me if I'm wrong but what you suggest only give me the option to read from the file and not write to it right? – Shahar Kazaz Sep 24 '13 at 15:34
When you want to write on this file you can not do it because the txt file is inside jar and it is read only. But if you want to write you should follow the first part of my answer. – Shamim Ahmmed Sep 24 '13 at 15:37

Jar can't access txt files

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