Develop Reference

Generate a file next to the jar file containing the code

I have a jar with my application that should create a file next to it. So in folder I will have this :
Source
|_ MyApplication.jar
|_ generatedFile.txt
Easy thing I thought... nope.. I am lost... I have a code like this:
URL location = MyClass.class.getProtectionDomain().getCodeSource().getLocation();
String path = location.getFile().substring(0, location.getFile().lastIndexOf("/MyContext"));
File file = new File(fileName + ".txt");
File file1 = new File(path + "/MyFileName.txt");
File file2 = new File(path.substring(1) + "/MyFileName.txt");
I tried different combinations, googled alot and I am lost... if I get for example
file1.getPath();
file2.getAbsolutePath();
and so on, the paths are correct... but the file isn't generated... Only working case is the first one, but that is located inside the jar and I don't want that.
I also tried to moving the existing file outside using
Paths.move(...
but that hasn't helped me at all..
Can someone help me with this ? And explain to me why isn't the examples above working ? Thanks..

The call File file = new File("my path string"); just creates a Java File Object instance in memory. You need to write something to the actual file you are targeting. The simplest way to create an empty file is to call file.createNewFile().

How to set file path to src folder of project

I want to make a program that you can email to someone and they can run it.
Right now my code for making a file is like this:
File f = new File("/Users/S0urceC0ded/Desktop/Code/project/JavaStuffs/src/axmlfile.xml);
f.createNewFile();
But what if someones username is not S0urceC0ded, or they put the project in a different place? How could I set the file path to the src folder plus the filename?

Leave the path off entirely, it will use the directory of the project.
Change
File f = new File("/Users/S0urceC0ded/Desktop/Code/project/JavaStuffs/src/axmlfile.xml");
To
File f = new File("axmlfile.xml");

I generally use code like this for temporary file storage, this way it gets cleaned up when the application finishes. If required you can allow the user to save a version of the file or move it to a permanent location.
try{
//create a temporary file
File temp = File.createTempFile("axmlfile", ".xml");
System.out.println("Location: " + temp.getAbsolutePath());
}catch(IOException e){
e.printStackTrace();
}

Reading .txt file from another directory

The code I am running is in /Test1/Example. If I need to read a .txt file in /Test1 how do I get Java to go back 1 level in the directory tree, and then read my .txt file
I have searched/googled and have not been able to find a way to read files in a different location.
I am running a java script in an .htm file located at /Test1/Test2/testing.htm. Where it says script src=" ". What would I put in the quotations to have it read from my file located at /Test1/example.txt.

In Java you can use getParentFile() to traverse up the tree. So you started your program in /Test1/Example directory. And you want to write your new file as /Test1/Example.txt
File currentDir = new File(".");
File parentDir = currentDir.getParentFile();
File newFile = new File(parentDir,"Example.txt");;
Obviously there are multiple ways to do this.

You should be able to use the parent directory reference of "../"
You may need to do checks on the OS to determine which directory separation you should be using ['\' compared to '/']

When you create a File object in Java, you can give it a pathname. You can either use an absolute pathname or a relative one. Using absolutes to do what you want would require:
File file = new File("/Test1/myFile.txt");
if(file.canRead())
{
// read file here
}
Using relatives paths if you want to run from the location /Test1/Example:
File file = new File("../myFile.txt");
if(file.canRead())
{
// read file here
}

I had a similar experience.
My requirement is: I have a file named "sample.json" under a directory "input", I have my java file named "JsonRead.java" under a directory "testcase". So, the entire folder structure will be like untitled/splunkAutomation/src and under this I have folders input, testcase.
once after you compile your program, you can see a input file copy named "sample.json" under a folder named "out/production/yourparentfolderabovesrc/input" and class file named "JsonRead.class" under a folder named "out/production/yourparentfolderabovesrc/testcase". So, during run time, Java will actually refer these files and NOT our actual .java file under "src".
So, my JsonRead.java looked like this,
package testcase;
import java.io.*;
import org.json.simple.JSONObject;
public class JsonRead{
public static void main(String[] args){
java.net.URL fileURL=JsonRead.class.getClass().getResource("/input/sample.json");
System.out.println("fileURL: "+fileURL);
File f = new File(fileURL.toURI());
System.out.println("fileIs: "+f);
}
}
This will give you the output like,
fileURL: file:/C:/Users/asanthal/untitled/out/production/splunkAutomation/input/sample.json
fileIs: C:\Users\asanthal\untitled\out\production\splunkAutomation\input\sample.json

It worked for me. I was saving all my classes on a folder but I needed to read an input file from the parent directory of my classes folder. This did the job.
String FileName = "Example.txt";
File parentDir = new File(".."); // New file (parent file ..)
File newFile = new File(parentDir,fileName); //open the file

Android writing to a CSV file via OpenCsv

I try to write to a Csv file via:
mFileWriter = new FileWriter(
"/sdcard/program/file");
mCsvWriter = new CSVWriter(mFileWriter);
At the moment it throws an exception that the file doesn't exist.
It's true that the file doesn't exist. What's the easiest way to create the file?

Does the FILE not exist, or the DIRECTORY it's supposed to go into?
If you want to create a directory structure, you can always do
File file = new File("/full/path/to/file");
file.mkdirs();
This will create any path leading up to this file that doesn't exist yet.
I suppose the missing quotes around your file name are a typo?

Java File manipulation

So I have an application with a JFileChooser from which I select a file to read. Then I change some words and write a new file. The problem that I am having is that when I write the new file it's saved in the project directory. How do I save it in the same directory as the file that I chose using the JFileChooser. Note: I don't want to use the JFileChooser to choose the location. I just need to save the file in the same directory as the original file that I read.

You choose a file like this:
File fileToRead = JFileChooser.getSelectedFile();
Then you read and change the content and write it back to the same location with a different name:
File fileToWrite = new File( fileToRead.getParent(), "newName.txt" );