Java：如何导出使用.txt文件的程序？

Question

I created a program which uses a .txt file and wan't to know how I can use the .txt file when my program is exported.

Just ignore the comments in the code

Scanner cl;

// Creating a JFrame for the change-log
JFrame changelogFrame;

JTextArea changelogText;
JScrollPane scroll;


// Open the change-log file & setup changelogFrame, changelogText and scroll
public void openChangelog() {

    // Setting up the changelogFrame
    changelogFrame = new JFrame();
    changelogFrame.setVisible(false);
    changelogFrame.setDefaultCloseOperation(HIDE_ON_CLOSE);
    changelogFrame.setSize(500, 500);
    changelogFrame.setLocationRelativeTo(null);
    changelogFrame.setTitle("Change-log");

    // Setting up the changelogText
    changelogText = new JTextArea();
    changelogText.setEditable(false);
    changelogText.setMargin(new Insets(5, 5, 5, 5));
    // Setting up the scroll (Scroll-pane for changelogText)
    scroll = new JScrollPane(changelogText, JScrollPane.VERTICAL_SCROLLBAR_AS_NEEDED, JScrollPane.HORIZONTAL_SCROLLBAR_AS_NEEDED);
    changelogFrame.add(scroll);

    try{
        cl = new Scanner(new File("Change-log.txt"));
    }
    catch(Exception e) {
        JOptionPane.showMessageDialog(null, "An error occurred while loading the changelog...", "Error loading changelog", JOptionPane.ERROR_MESSAGE);
    }
}

// Read the change-log file
public void readChangelog() {
    cl.useDelimiter("\\Z");
    String loadChangelog = cl.next();

    changelogText.setText(loadChangelog);
    changelogFrame.setVisible(true);


}

// Close the change-log file
public void closeChangelog() {
    cl.close();
}

When I export my program to a Runnable JAR file and try to load the Change-log.txt it won't load. I get the error message.
How can I export my program and use the Change-log.txt without any errors? Is the Change-log.txt not being exported with the source code?

Answer 1

You should include the exceptions message in your error-message. That way, you'll have more information on what goes wrong, and can debug this yourself.

I would assume that the file you want to read out from does not exist in the folder your exported program is executed in. In that case, you either need to handle this case, or create it, depending on your end-goal.

Answer 2

Simple and short method of doing this (while cutting some corners) using part of your code is:

String path = System.getProperty("user.home");
path = (path+"\\Change-log.txt")

cl = new Scanner(new File(path));`

This way you always place the file into users home directory, where the read/write privileges are ussually given, and you can also write that file there with some other method, following the same structure I have given you

You will probably also need to write a piece of code that generates the changelog for the user, if it is not present in the home dir.