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How to attach file to jar that can be edited inside this jar?

I am making a program that works with MySQL database,for now i store URL, login, password e.t.c as public static String. Now i need to make it possible to work on another computer, so database adress will vary, so i need a way to edit it inside programm and save. I would like to use just external txt file, but i don't know how to point it's location.
I decided to make it using Property file, i put it in src/res folder. It work correct while i'm trying it inside Intellij Idea, but when i build jar (artifact) i get java.io.FileNotFoundException
I tried two ways:
This one was just copied
private String getFile(String fileName) {
StringBuilder result = new StringBuilder("");
//Get file from resources folder
ClassLoader classLoader = getClass().getClassLoader();
File file = new File(classLoader.getResource(fileName).getFile());
System.out.println(file.length());
try (Scanner scanner = new Scanner(file)) {
while (scanner.hasNextLine()) {
String line = scanner.nextLine();
result.append(line).append("\n");
}
scanner.close();
} catch (IOException e) {
e.printStackTrace();
}
return result.toString();
}
System.out.println(obj.getFile("res/cfg.txt"));</code>
And second one using Properties class:
try(FileReader reader = new FileReader("src/res/cfg.txt")) {
Properties properties = new Properties();
properties.load(reader);
System.out.println(properties.get("password"));
}catch (Exception e) {
e.printStackTrace();
System.out.println(e);
}
In both ways i get java.io.FileNotFoundException. What is right way to attach config file like that?

Since the file is inside a .JAR, it can't be accessed via new File(), but you can still read it via the ClassLoader:
Properties properties = new Properties();
try (InputStream stream = getClass().getResourceAsStream("/res/cfg.txt")) {
properties.load(stream);
}
Note that a JAR is read-only. So this approach won't work.
If you want to have editable configuration, you should place your cfg.txt outside the JAR and read it from the filesystem. For example like this:
Properties properties = new Properties();
File appPath = new File(MyClass.class.getProtectionDomain().getCodeSource().getLocation().toURI()).getParentFile();
try (InputStream stream = new FileInputStream(new File(appPath, "cfg.txt"))) {
properties.load(stream);
}

There are multiple places your can place your configuration options, and a robust deployment strategy will utilize some (or all) of the following techniques:
Storing configuration files in a well known location relative to the user's home folder as I mentioned in the comments. This works on Windows (C:\Users\efrisch), Linux (/home/efrisch) and Mac (/Users/efrisch)
File f = new File(System.getProperty("user.home"), "my-settings.txt");
Reading environment variables to control it
File f = new File(System.getenv("DEPLOY_DIR"), "my-settings.txt");
Using a decentralized service such as Apache ZooKeeper to store your database settings
Use Standalone JNDI
(or the JNDI built-in to your deployment target)
Use a Connection Pool

Properties file reads old data when jar is executed from command line

I have created a java application that copies data from properties file (resources-> settings -> config.properties) and uses it. At one point the properties file values are updated and the code has to use the new values. The code works fine when executed from Netbeans. But when I execute ti from the dist folder after build, the old values get loaded everytime even when I change the the properties file. The properties file gets updated but the values used are still the old ones.
Code to write properties file
File f = new File(System.getProperty("user.dir") + "\\resources\\settings\\config.properties");
try (OutputStream output = new FileOutputStream(f)) {
Properties prop = new Properties();
// set the properties value
prop.setProperty("xml", xmlFileTextBox.getText());
// save properties to project root folder.
prop.store(output, null);
} catch (IOException exception) {
exception.printStackTrace();
}
Code to read values in properties file
try {
Properties prop = new Properties();
String propFileName = "settings/config.properties";
try (InputStream inputStream = getClass().getClassLoader().getResourceAsStream(propFileName)) {
if (inputStream != null) {
prop.load(inputStream);
xmlFileTextBox.setText(prop.getProperty("xml"));
}
inputStream.close();
}
} catch (Exception e) {
System.out.println("Exception: " + e);}

The file you are reading from is a file that is packaged with your application and not the file you are saving to.
This code, getClass().getClassLoader().getResourceAsStream(propFileName)), gives you a resource from the classpath.
You need to create the File in the same way as when you save the properties, then get the InputStream from that File.
If you want to have the defaults in your original properties file you might need to check for null in the "save file" and if it don't have data then read from your default resourse file.

Assigning a destination for properties file in a java program

Sorry if this seems like a newbie question and im sure its just a little thing i need to change but it seems like my program cannot locate the destination for a properties file i coded in.
here is my code
public String metrics() throws IOException {
String result = "";
Properties prop = new Properties();
String propFileName = "C:\\Users\\JChoi\\Desktop\\config.properties";
InputStream inputStream = getClass().getClassLoader().getResourceAsStream(propFileName);
prop.load(inputStream);
if (inputStream == null) {
throw new FileNotFoundException("property file '" + propFileName + "' not found in the classpath");
}
// get the property value and print it out
String Metrics = prop.getProperty("Metrics");
result = Metrics;
System.out.println(result);
return result;
}
I get a nullpointerexception error everytime i run the code but however, when i put the properties file in the resources folder and edit the string name to...
String propFileName = "config.properties";
works fine...any suggestions?
EDIT:
String result = "";
Properties prop = new Properties();
String propFileName = "C:\\Users\\JChoi\\Desktop\\config.properties";
FileInputStream fileInputStream = getClass().getClassLoader().getResourceAsStream(propFileName);
prop.load(fileInputStream);
SOLVED!
String propFileName = "C:\\Users\\JChoi\\Desktop\\googlebatchfile\\config.properties";
BufferedInputStream inputStream;
FileInputStream fileInputStream = new FileInputStream(propFileName);
inputStream = new BufferedInputStream(fileInputStream);

If you know the full path to a file, then do not try to open it using a classpath search (which is what getResourceAsStream() does).
Instead open the file using an inputsteam that takes a path.
Here is some code:
FileInputStream inputStream = new FileInputStream(propFileName);
The following might be a better technique (I'm not sure with property loading):
BufferedInputStream inputStream;
FileInputStream fileInputStream = new FileInputStream(propFileName);
inputStream = new BufferedInputStream(fileInputStream);

You are attempting to load a file using a classpath-based input stream but specifying a filepath.
This:
getClass().getClassLoader().getResourceAsStream(propFileName);
Will attempt to search the classpath starting at the root (based on whatever the classloader considers the root).
If you want to load a file from outside the classpath, you probably just want to use something like a FileInputStream instead.

Java properties not loading

I am trying to set up a java .properties file outside of the packaged jar. This is my code to load it:
public static final String FILENAME = "test.properties";
public static void load() throws IOException {
FileInputStream fis = null;
try {
props = new Properties();
fis = new FileInputStream(FILENAME);
props.load(fis);
System.out.println("Properties successfully loaded: "+props);
validateProperties();
} catch (FileNotFoundException e) {
System.err.println("Properties file not found. Creating...");
new File(FILENAME).createNewFile();
//fill with default properties
System.out.println("Properties file successfully created");
} finally {
if (fis != null) try {fis.close();} catch(Exception e) {}
}
}
Unfortunately, when I run this, I get the following output:
Properties successfully loaded: {}
Here is test.properties:
#no comment
#Sun Jun 23 19:21:45 CDT 2013
port=55142
handSize=10
maxPlayers=8
timeout=1500
I have confirmed, by manually reading and printing, that the FileInputStream is reading from the correct file. So why aren't my properties loading?
EDIT: Here is some code which loads the contents of the properties file directly:
public static void test() throws IOException {
FileInputStream fis = new FileInputStream(FILENAME);
byte[] b = new byte[fis.available()];
fis.read(b);
String text = new String(b);
System.out.println(text);
}
and it outputs:
#no comment
#Sun Jun 23 19:21:45 CDT 2013
port=55142
handSize=10
maxPlayers=8
timeout=500
so the FIS must be reading from the correct file.
EDIT 2: Ok, so I don't know what the problem was, but I restarted eclipse and now it's working. Very sorry to have wasted your time.

Check what line separator your java system uses. Eg:
System.out.println((int)System.getProperty("line.separator").charAt(0));
On UNIX that will give 10, which is newline \n, on Windows that will be 13 (eg: the first char of \r\n).
I think your java code is reading the file using Windows encoding, yet the property file is edited in UNIX, hence everyting appears to be in "one single line" -- which will result in empty properties because your first line is commented

As your properties file is not present in the classpath so you cannot read it without giving the proper path. There are multiple approaches to read an external properties file from a jar. One of the simplest way is to use the -D switch to define a system property on a java command line. That system property may contain a path to your properties file.
E.g
java -cp ... -Dmy.app.properties=/path/to/test.properties my.package.App
Then, in your code you can do :
public static final String FILENAME = "test.properties";
public static void load() throws IOException {
FileInputStream fis = null;
String propPath = System.getProperty(FILENAME);
try {
props = new Properties();
fis = new FileInputStream(propPath);
props.load(fis);
System.out.println("Properties successfully loaded: "+props);
validateProperties();
} catch (FileNotFoundException e) {
System.err.println("Properties file not found. Creating...");
new File(propPath ).createNewFile();
//fill with default properties
System.out.println("Properties file successfully created");
} finally {
if (fis != null) try {fis.close();} catch(Exception e) {}
}
}

When there is no absolute path mentioned, JVM tries to load resources from the JVM & project classpath. In your case, empty output signifies that JVM is trying to load property file from classpath but the file is not there.
Solutions:
1) Either place your property file in your classpath
2) Or mention absolute path to property file.

A ResourceBundle offers a very easy way to access key/value pairs in a properties file in a Java...
You can refer following.
http://www.avajava.com/tutorials/lessons/how-do-i-read-a-properties-file-with-a-resource-bundle.html
You can directly specify your properties file name while loading the bundle when it is present in the same folder as your jar/classes.

Writing to a properties file does not work

I want to write into a *.properties file. Thats my code how I do this:
properties = loadProperties("user.properties");//loads the properties file
properties.setProperty(username, password);
try {
properties.store(new FileOutputStream("user.properties"), null);
System.out.println("Wrote to propteries file!" + username + " " + password);
I do not get an exception, but I also do not get the output written into the file.
Here is also my file-structure:
I appreciate your answer!!!
UPDATE
I load my properties file with:
InputStream in = ClassLoader.getSystemResourceAsStream(filename);
My question is, how to load it from a specific path?
Here is my "new" File Structure:

Here is my testing code:
#Test
public void fileTest() throws FileNotFoundException, IOException {
File file = null;
Properties props = new Properties();
props.setProperty("Hello", "World");
URL url = Thread.currentThread().getContextClassLoader()
.getResource("exceptions/user.properties");
try {
file = new File(url.toURI().getPath());
assertTrue(file.exists());
} catch (URISyntaxException e) {
e.printStackTrace();
}
props.store(new FileOutputStream(file), "OMG, It werks!");
}
It does creates and rewrites a file in my target/classes/exceptions directory (in a maven/eclipse proyect) so I guess it really works, but of course that is not tested in a JAR file.
Here is the file:
#OMG, It werks!
#Sat Nov 10 08:32:44 CST 2012
Hello=World
Also, check this question: How can i save a file to the class path
So maybe what you want to do never will work.