Static method to read text file within JAR.

Question

I've a small problem. I've got my JAR file stuff working great, so I thought I'd give a go to running it via WebStart. Through a little research, I've found that if you're distributing your application via WebStart, you need to pack up everything in a JAR file. This is no problem for the JDBC drivers, because its already in a JAR, so I should be able to distribute that fine.
I've managed to digitally sign my application JAR and have a preliminary (i.e. untested) JNLP file set up.
My problem is, my application gets its available data sources from an external text file. I've already written my own file I/O class which I use in my "commonfiles" package to read in a text file and return it as an array with each element holding a line from the text file. This class is basically just a bunch of static methods.
So instead of rewriting this, I thought I'd just add a boolean flag to this method to state whether to load this file from the external file system or the JAR file. I've found out that to load a text file from within the JAR you have to use something like: -
String str = (this.getClass().getResource("/myData.txt")).getFile();
java.io.File fil = new java.io.File(str);
java.io.FileReader fr = new java.io.FileReader (fil);
java.io.BufferedReader bin = new java.io.BufferedReader (fr) ;The sticking point is that my method (ReturnFileAsArray()) is declared as static, because my own FileIO class is just a bunch of static methods to do file I/O stuff. Therefore, I can't use the above method because of the instance variable "this" (I assume).
Is there any way I can load an included text file as above without having to declare my method as an instance method? I guess I could write a seperate class to do this for my commonfiles package, but I'd rather not if possible.
Any ideas?

Answer 1

Don't put a "flag" and code different ways to read files depending on whether it's in a JAR or not. Just use
the getResource/getResourceAsStream API regardless. Hmmm.....so that will load it from either place depending on the situation? I keep getting a NullPointerException doing that, on this line: -
String strFileName = (FileIO.class.getResource(fileName)).getFile();...although I've only tried it using the external local filesystem file (in the same directory) as I've not really finished setting up my WebStart stuff yet.
Here is the method in question...
public static String[] ReadFileAsArray(String dirName, String fileName, boolean bFromJAR) {
        String[] resultStringArray = null;
        StringBuffer strBuffer = null;
        StringTokenizer strTokenizer = null;
        FileReader fReader = null;
        BufferedReader bReader = null;
        int iElementCount = 0;
        if ((dirName.length() < 1) || (fileName.length() < 1)) {
            // Null parameters found. Failure.
            return null;
        } else {
            // Parameters correct, continue.
            try {
                // Read the file contents and convert to String array.
                //if (bFromJAR) {
                    // Open file from within JAR file.
                    String strFileName = (FileIO.class.getResource(fileName)).getFile();
                    File jarFile = new File(strFileName);
                    fReader = new FileReader(jarFile);
                //} else {
                    // Open from local filesystem.
                //    fReader = new FileReader(dirName + File.separator + fileName);
                bReader = new BufferedReader(fReader);
                strBuffer = new StringBuffer();
                while (bReader.ready()) {
                    strBuffer.append(bReader.readLine() + "%%");
                strTokenizer = new StringTokenizer(strBuffer.toString(), "%%");
                resultStringArray = new String[strTokenizer.countTokens()];
                while ((strTokenizer.hasMoreTokens()) && (iElementCount < resultStringArray.length)) {
                    resultStringArray[iElementCount++] = strTokenizer.nextToken();
                bReader.close();
                return resultStringArray;
            } catch (IOException e) {
                return null;
    }I'm calling it using: -
// Load the external file into a String array, one row for each element.
String[] fileArray = FileIO.ReadFileAsArray(System.getProperty("user.dir"), "datasources.dat", true);Cheers on any info on this.