Whenever you are working with files in Java, sometimes you need to get the full path to the directory the .jar file is located in. Most of the time you can just use
.String path = "./File_Name.txt"; // Note the "." before the "/"
.
when dealing with reading/writing/creating files and directories - HOWEVER for those times when that is not enough, you'll need to extract a "clean" path to the .jar file.
Below is a simplified example that does exactly this. I cut out all of the unnecessary, over complicated, and/or outdated items you may find in other posts about this subject.
I will explain how it works as we go along.
.public class Main { public static void main (String[] args) throws Exception { String i; // ignore - not important String pathName; // path to create new file String fileName; // name of new file File file; // File object to create i = "\n**********\n"; // ignore - not important fileName = "/Test_File.txt"; // set the file name pathName = Main.class.getProtectionDomain().getCodeSource().getLocation().getPath(); // get the path of the .jar pathName = URLDecoder.decode(pathName,"utf-8"); // convert the path format from HTML to UTF pathName = pathName.substring(1,pathName.lastIndexOf("/") ); //create a new string by removing the garbage System.out.println(i + pathName + fileName + i ); // this is for debugging - see the results file = new File(pathName + fileName); // create file file.createNewFile(); // make new file }}
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.pathName = Main.class.getProtectionDomain().getCodeSource().getLocation().getPath();
.
This returns the *raw* path of the .jar file in a HTML format with some extra junk that is not needed. Using ".toURI()", ".toURL()" and ".toString() is not necessary AND will create more junk in the path name!
.[quote]

C:\Users\RICK\Desktop>java -jar test1111.jar

**********
/C:/Users/RICK/Desktop/Test1111.jar
**********
[/quote]
.
Note: If you have any directories with special characters in them, you will end up with the HTML equivalent ... "%20" instead of " " for example.
The next line parses the HTML format into UTF, which Java can understand as a path name
.pathName = URLDecoder.decode(pathName,"utf-8");
.
This cleans up the HTML format, but leaves some junk behind
.[quote]

C:\Users\RICK\Desktop>java -jar test1111.jar

**********
/C:/Users/RICK/Desktop/Test1111.jar
**********[/quote]
.
Now we need to remove the junk, and create a usable path for Java to use
.pathName = pathName.substring(1,pathName.lastIndexOf("/") );
.
This removed the first "/" from the string, and also cuts off the name of the .jar file !

This creates a usable path name, to be used, in this example, to make a file
.file = new File(pathName + fileName); file.createNewFile();
.
.[quote]

C:\Users\RICK\Desktop>java -jar test1111.jar

**********
C:/Users/RICK/Desktop/Test_File.txt
**********[/quote]
.
Thank you for reading. Please leave feedback below !