How to run a Java program on all files in a directory from command line

Question

I've got this java program which is currently programmed to take in a filename as an argument from command line, open it and then read it. I want to configure it so I can pass it a directory name and the program will execute on the files in the directory. Not really sure how to go about it. This is my code currently:

static XMLInputFactory factory = XMLInputFactory.newInstance(); 
XMLEventReader reader = null;  
XMLEventFactory eventFactory = null;

public XMLTrimmer(File ifp) throws XMLStreamException, FileNotFoundException {
    this(new FileInputStream(ifp));
}

public XMLTrimmer(InputStream str) throws XMLStreamException, FileNotFoundException {
    try {
        reader = factory.createXMLEventReader(str);
    } catch (XMLStreamException e) {
        e.printStackTrace();
    }
}

In main it goes like this:

public static void main(String args[]) throws IOException, XMLStreamException {

    File readFile = new File(args[0]);

    XMLTrimmer xr = new XMLTrimmer(readFile);

please let me know, any help is appreciated.

Are you wanting your java code to do this or are you OK to have a script run your java code for each file in the directory? — user3885927, Aug 27 '14 at 21:13
Only two options: Change the program to take multiple arguments and/or check if an arg is really a directory (J4v4's answer) or write a script or batch file that calls the program once for each file — Gus, Aug 27 '14 at 21:15

score 3 · Accepted Answer · answered Aug 27 '14 at 21:03

You will have to modify the code to check if the argument points to a directory:

if(readFile.isDirectory()) {
    for(File file : readFile.listFiles()) {
        //process all files in the directory
    }
} else {
    //process single file
}

You can also add support for more than one argument (since args is an array of Strings) or no argument.

score 0 · Answer 2 · answered Aug 27 '14 at 21:25

If you want to go through all files recursively you might rather need

public static void main(String[] args) {
    File readFile = new File(args[0]);

    executeForPath(readFile);
}

private static void executeForPath(File readFile) {
    if (readFile.isDirectory()) {
        for (File file : readFile.listFiles()) {
            executeForPath(file);
        }
    } else {
        XMLTrimmer xr = new XMLTrimmer(readFile);
    }
}

How to run a Java program on all files in a directory from command line

2 Answers2