send java class instance from javascript (via ajax) to jsp or servlet

Question

I am trying to send the JAVA CLASS INSTANCE from my javascript code to the JSP file via ajax . How can i send ? I tried sending the instance like this :

   data = {}
   data['my_instance'] = JAVA_CLASS_INSTANCE

and sending this data via ajax , problem is , in JSP, it is receiving it as a string rather than a class

By the way, I am getting the java class instance like this :

<script type='text/javascript'>
     var class_instance = "<%= my_class_instance %>"; //if this method is wrong, plz tell me correct method to get instance and send via ajax. Already I have a form, along with the form data, i am trying to send this class also. If there is anyother good way for this, just tell me. 
</script>

Answer 1

(Updated below)

Fundamentally, what you send from the client to the server via ajax is always a string. It can only be turned into something else by a server-side process interpreting it.

The question doesn't seem to make any sense. Unless you're using a Java applet on the client and LiveConnect, you don't have a Java class instance on the client at all.

If you did have a Java class instance on the client (e.g., from the applet), the only way to send it to the server would be:

1. Serialize it to a byte stream.

2. Encode that byte stream into a string (Base64 or similar).

3. Send that encoded string to the server via ajax.

4. Decode the string back into a byte stream on the server.

5. Deserialize it on the server.

...and there would almost certainly be a much better way of getting that information from the client to the server.

---

You've edited your question to say:

By the way, I am getting the java class instance like this :

<script type='text/javascript'>
     var class_instance = "<%= my_class_instance %>";
</script>

That won't give you a "Java class instance" on the browser. At best, you'll have a string with some information in it. More likely, depending on what's inside your my_class_instance server-side variable, you'll have a JavaScript syntax error. (E.g., if you have a ' or a line break or an invalid JavaScript escape sequence, etc., inside it.)

If you believe that's a Java class instance, you need to step back and study the fundamentals of web applications before trying to write this code.

Answer 2

You are writing scriptlet to your jsp. This is a bad thing 99.9% of times. You should avoid it all the times. Most of the case, you can write it better with the jstl.

And more importantly, your code is not going to put the java object instance to client browser. It's totally wrong.

Please take a look. How to avoid using scriptlets in my JSP page?