jsp - Call Servlet and invoke Java code from JavaScript along with parameters -

I have a session key that is a JavaScript variable that I received from a REST API call. I have to call my Java code in servlet and pass that key as a parameter

In many ways:

1. Use window.location to set a GET request. The warning is that it is synchronous (hence the customer current page Will see changing).

     window.location = "http://example.com/servlet?key=" + encodeurIComponent  

   before requesting the parameter to the request parameter Note the importance of the built-in encodeurIComponent () function to convert into words.

2. Use form.submit () to fire the GET or POST request. The warning is also that it is synchronous.

     document.formname .key.value = key; Document.formname.submit ();  

     & lt; Form name = "formname" action = "servlet" method = "post" & gt; & Lt; Input type = "hidden" name = "key" & gt; & Lt; / Form & gt;  

   Alternatively, you can also just set the hidden area of ​​an existing form and wait for the user to submit it.

3. Use XMLHttpRequest # send () An asynchronous request in the fire (also known as Ajax) to fire. Example below servlet "s doGet () .

     var xhr = new XMLHttpRequest (); xhr.open (" GET "," http: // Example ". Com / servlet? Key = "+ encodeurcomponent (key)); Xhr.send (null);    "Post", "http://example.com/servlet"); Xhr.send ("key =" + encodeurIC component (key));  

4. Use to send a crossbrowser compatible Ajax request (above xhr code works in real browsers only, for MSIE compatibility, you "(" http: //example.com/servlet " , {"Key": key});

   Note that jQuery's already transparent request parameters automatically encode all the way, so come Should not be " encodeurIComponent () .

Any method, key just request.getParameter ( "Key") will be available in servlet by .

Also see: