Running Javascript from Java (but need jQuery, DOM and ajax)

Question

I'm building a web app with Diagram in it.

For the diagram I used jsPlumb library Link: https://jsplumbtoolkit.com/

One of my requirement is to make Blocks inside the Diagram like flowchart. And one type of the blocks is a able to be inserted by customizable script. So, when user double-clicked that block, they can input Javascript code in the textarea and will be executed later.

Here lies my problem : I able to run the script code very well, when it is still on the front-end side (jsp) using browser using "new Function" from Javascript. But after the block is saved, the script saved to DB. And if I need to run it again, then it will be executed from back-end (Java).

Therefore, I used ScriptEngine to run the Javascript. The problem is ajax, $-sign, console, etc are not recognized from Java. And I found out later, that ScriptEngine did not support for those kind of things.

So, I wonder is there is any possible way to make these possible ? I'm open to other alternative idea.

Thank you

• Reporter: According documentation ajax is supported by this library.
• Lyn: @reporter I see, but the $-sign just before ajax ($.ajax) is not recognized
• Reporter: This lib uses a different syntax.

Answer 1

Use HtmlUnit Java Library

Sample code

final WebClient webClient = new WebClient(BrowserVersion.CHROME);
final HtmlPage page = webClient.getPage("http://127.0.0.1:9090/mysite");
page.executeJavaScript("$");
webClient.close();

This http://127.0.0.1:9090/mysite can be your local website which already has jquery

You can also inject a script tag on the fly in a blank html page

If your are behind a proxy then

final WebClient webClient = new WebClient(BrowserVersion.CHROME, "proxyhost", 8080);

Alternate Idea

Use Jaunt - Java Web Scraping & JSON Querying Java Library

Sample code and full documentation available in the site

• Lyn: final WebClient webClient = new WebClient(BrowserVersion.CHROME); The first line already indicating that I might need to anticipated all kind of browsers to use this. Regardless of that, Thank you for your idea. I will try it and see if it will work.