Extract DLL from Jar

Question

I have a project set up with a resources directory similar to this:

[Project]
    [java]
        MainClass
        ...
        ...
    [resources]
        MyDll.dll

I want to be able to load MyDll.dll using System.load(). I read that to be able to do this from the jar, I need to first extract the dll to a temporary location. I am currently using this code to do so:

try {
    InputStream input = this.class.getResourceAsStream("MyDll.dll");

    byte[] buffer = new byte[1024];
    int read = -1;
    File temp = File.createTempFile("MyDll.dll", "");
    FileOutputStream output = new FileOutputStream(temp);

    while ((read = input.read(buffer)) != -1) {
        output.write(buffer, 0, read);
    }
    output.close();
    input.close();

    System.load(temp.getAbsolutePath());
} catch (Exception e) {
    e.printStackTrace();
}

However, I think it's not finding the file. input is always null. Is there a way I can locate MyDll.dll in the resources folder?

George Vassilev · Answer 1 · 2015-12-29T09:55:13.993

0

    InputStream input = this.getClass().getClassLoader().getResourceAsStream("MyDll.dll");

edited Dec 29 '15 at 09:55

answered Dec 29 '15 at 08:55

George Vassilev

129
10

Unfortunately, this did not work. It still returns null. – Panda Dec 29 '15 at 09:03
@grandmind1 try with classloader, and you are sure that the file exists ? ) – George Vassilev Dec 29 '15 at 09:56
Code only answers are usually not helpful. Add some explanation. – Manos Nikolaidis Dec 29 '15 at 10:36

Extract DLL from Jar

1 Answers1