run java in javascript

Question

I am making a function that compares two pictures if they are the same. I have this code:

var rez = null;

rez = compareImages();

alert(rez);


boolean
function compareImages() {
  BufferedImage bi1 = java.ImageIO.read(new File("C:\\MyFiles\\pic1.png")),
    bi2 = java.ImageIO.read(new File("C:\\MyFiles\\pic2.png"));
  Raster r1 = bi1.getData(),
    r2 = bi2.getData();
  DataBuffer db1 = r1.getDataBuffer(),
    db2 = r2.getDataBuffer();
  int size1 = db1.getSize(),
    size2 = db2.getSize();

  // checking if the files sizes are the same
  if (size1 != size2)
    return false;

  // pixel by pixel check up
  for (int i = 0; i < size1; i++)
    if (db1.getElem(i) != db2.getElem(i))
      return false;

  return true;
}

Now I want to run this code in .js file but when I do I get an error, missing ";" error. So how do I make this function javascript compatible ?

Thanks.

Write the javascript bytecode interpreter, that will prob help you. — Roman C
– Roman C, Commented Nov 17, 2012 at 0:37

Nico Burns · Accepted Answer · 2012-11-17 00:22:07Z

4

Unfortunately Javacript and Java are completely seperate languages, and the only thing which they have in common in the name, therefore this is impossible.

If you want to learn about doing something similar in javascript then take a look at the File API's: https://developer.mozilla.org/en-US/docs/DOM/File_APIs

answered Nov 17, 2012 at 0:22

Nico Burns

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1 Comment

edinvnode Over a year ago

Yeah but check this out ` //Function to write the file function writeFile(filename, data) { try { //write the data out = new java.io.BufferedWriter(new java.io.FileWriter(filename, true)); out.newLine(); out.write(data); out.close(); out=null; } catch(e) //catch and report any errors { alert(""+e); } } ` This is en example of how java is being called to open and write data into a .csv file. So there is a way to run java in javascript. Right? I hope you can read the code.

jangxx · Accepted Answer · 2012-11-17 00:24:18Z

3

You can't run Java code in JavaScript. You can either compile your Java code as an applet and embed that in you page, or you just rewrite your code in JS. If you use the html5 canvas and the getImageData() function, this should be doable. That way you can easily interact with your code from JavaScript.

answered Nov 17, 2012 at 0:24

jangxx

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3 Comments

edinvnode Over a year ago

Ok, so you are telling me I can do this operation (compare two images) ij JS. What is the code for that?

jangxx Over a year ago

Okay, I threw this together: jsfiddle.net/tETdW/11 It might not work if you use it on jsfiddle because of the cross-domain policy, but if the images an the js are on the same server there should be no problem. Alternatively, you can use this image for testing: jangxx.com/images/megaman_mc.png (my avatar).

edinvnode Over a year ago

Thanks. This is by far the best solution.

Natix · Accepted Answer · 2012-11-17 01:40:34Z

1

It is somewhat possible to use Java classes and APIs in code that you write in JavaScript with Mozilla Rhino.

Rhino is simply a JS interpret written in Java that is bundled with the JDK. It basically allows you to use the Java APIs with JS syntax, but on the other hand, there is no DOM API available and you can't run such scripts in a Web browser. They are run by the JVM.

edited Nov 17, 2012 at 1:40

answered Nov 17, 2012 at 1:35

Natix

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