Cannot read image in jar

Question

i have written a program to encrypt an image in Netbeans. The program works fine when running from netbeans but when i build it into a .jar file its not working, it cannot read the image even though i placed the image file in the same folder as the .jar file.

    package test;

    import java.io.IOException;
    import java.io.File;
    /**
     *
 * @author AMaR
*/
public class Test {

/**
 * @param args the command line arguments
 */
public static void main(String[] args) throws IOException, Exception {


    File EnImage = new File("encrypted.png");
    File DeImage = new File("decrypted.png");
    int[] pixels;

    LoadImage l = new LoadImage();
    l.load();
    pixels= l.getImagePixels();

    RC4New rc4 = new RC4New();
    int key[]= {13,2,4,6,};
  //  int data[]={5,10,90,5};
    rc4.KSA(key);
    int[] text = rc4.PRNG(pixels);
    l.write((int)512,(int)512,text,EnImage);

    //RC4New rc41 = new RC4New();
    rc4.KSA(key);
    int[] text1 = rc4.PRNG(text);
    l.write((int)512,(int)512,text1,DeImage);



 /*   for(int i=0;i<text.length;i++){
        System.out.println(text[i]);
    }

     RC4New rc41 = new RC4New();
     rc4.KSA(key);
    int[] text1 = rc4.PRNG(text); 
     for(int i=0;i<text1.length;i++){
        System.out.println(text1[i]);
    }

   */ 
    System.out.println("length:"+pixels.length);
  //  l.write((int)512,(int)512,text);

    // TODO code application logic here
}
    } 

//encryption

 package test;

 /**
     *
 * @author AMaR
 */
 public class RC4New {
 int state[] = new int[256];

 int j;
 /**
 *
 * @param key
 */
public void KSA(int[] key){ 

    int tmp;
    for (int i=0; i < 256; i++) {
        state[i] = i;
    }

    j=0;

    for (int i=0; i < 256; i++) {

       j = (j + state[i] + key[i % key.length]) % 256;
        tmp = state[i];
        state[i] = state[j];
        state[j] = tmp;
    }
}
    public int[] PRNG(int[] data){
    int tmp,k;
    int i=0;
    j=0;
    int[] cipherText = new int[data.length];
    for(int x=0;x<data.length;x++){
        i = (i + 1) % 256;
        j = (j + state[i]) % 256;
        tmp = state[i];
        state[i] = state[j];
        state[j] = tmp;
        k = state[(state[i] + state[j]) % 256];
        cipherText[x]=  (data[x] ^ k);
    }
    return cipherText;



    }


    }

//loading/writing image

    package test;

    import java.awt.Dimension;
    import java.awt.image.BufferedImage;
    import java.awt.image.Raster;
    import java.io.IOException;
    import javax.imageio.ImageIO;
    import java.io.File;
    import java.awt.image.WritableRaster;
    /**
    *
    * @author AMaR
    */


    public class LoadImage {
      BufferedImage image;
      void load()throws Exception { 

   //  FIle newfile = new File("lena.png)

     image = ImageIO.read(getClass().getResourceAsStream("lena.png"));
    }
    public Dimension getImageSize() {
    return new Dimension(image.getWidth(), image.getHeight());
    }

   public int[] getImagePixels() {
    int [] dummy = null;
    int wid, hgt;

   // compute size of the array
    wid = image.getWidth();
    hgt = image.getHeight();

   // start getting the pixels
   Raster pixelData;
   pixelData = image.getData();
   return pixelData.getPixels(0, 0, wid, hgt, dummy);


   }
    @SuppressWarnings("empty-statement")
   public void write(int width ,int height, int[] pixels,File outputfile) {

       try {
   // retrieve image
    BufferedImage writeImage = new BufferedImage(512, 512, BufferedImage.TYPE_BYTE_GRAY);;
     // File outputfile = new File("encrypted.png");
    WritableRaster raster = (WritableRaster) writeImage.getData();
    raster.setPixels(0,0,width,height,pixels);
    writeImage.setData(raster);
    ImageIO.write(writeImage, "png", outputfile);

    } catch (IOException e) {
      }

     }
    }

Answer 1

It's not clear which of the below is triggering your error. This

 File EnImage = new File("encrypted.png");

will read from the current directory, which is not necessarily the same directory as that your jar file is in.

This

image = ImageIO.read(getClass().getResourceAsStream("lena.png"));

will read from the directory in the jar file that your class is in. Note that you're reading from the jar file, not the directory.

Given the above code, I would:

1. determine or explicitly specify the working directory for the File() operations. Your working directory is the one you invoke java from, and this may differ within/without the IDE
2. package the lena.png as a resource within your .jar file.