How to encode request parameters?

Question

Hi I'm running a small web application developed with JSP pages. But it turns out that it relies on cookies to maintain sessions, which is a limitation if the client's cookie setting disables cookies.
I know that I could encode the request parameters and use GET method to communicate information between client and server, but have no idea how this is done.
Can you give me some code, or recommend some tutorial to me? Thanks!

Answer 1

1. If you don't want to use cookies, you could use URL rewriting to append the session ID. When you redirect to another page, do something like the following:
a. first choose whether you want to forward or sendRedirect: (the following example is a redirect)
//encode the parameter values to encode special characters, such as spaces
String parameterOne = java.net.URLEncoder.encode("some value");
String parameterTwo = java.net.URLEncoder.encode("some other value");
//build the query string any way you want
String queryString="?key1="+parameterOne+"&key2="+parameterTwo;
/* Use response.encodeRedirectURL if running it through a sendRedirect.
   Doing so will rewrite the url with the session ID appended to the
   end. */
response.sendRedirect(response.encodeRedirectURL("some.jsp"+queryString));This little code snippet demonstrates two things. It shows that URL rewriting can be used to append the session ID. It also shows you how to encode parameters (i.e. use URLEncoder.encode()).
If you want to encode your string in the JSP, you could also do it using javascript:
<script language="JavaScript">
<!--
   //this is just an example javascript function
   function openPage() {
      var thisForm=document.formName;
      /* get your form element values (these are text boxes).
         Note: the javascript escape() function url encodes the values.
               there are also other js functions to do this. */
      var paramOne=escape(thisForm.paramOne);
      var paramTwo=escape(thisForm.paramTwo);
      var queryString="?paramOne="+paramOne+"&paramTwo="+paramTwo;
      window.open("some.jsp"+queryString,"some_window_name");
   }//end openPage
//-->
</script>Or, you could build it using JSP expressions and scriptlets. Its really up to you. These are just rudimentary examples to help you get started.