Head First Servlets and JSP, 2nd Edition

Sending and using TWO parameters

HTML form

HTTP POST request

Servlet class

public void doPost(HttpServletRequest request, HttpServletResponse response)
                                             throws IOException, ServletException {
   String colorParam = request.getParameter("color");
   String bodyParam = request.getParameter("body");
     // more code here
}

Note

Now the String variable colorParam has a value of “dark” and bodyParam has a value of “heavy”.

Watch it!

You can have multiple values for a single parameter! That means you’ll need getParameterValues() that returns an array, instead of getParameter() that returns a String.

Some form input types, like a set of checkboxes, can have more than one value. That means a single parameter (“sizes”, for example) will have multiple values, depending on how many boxes the user checked off. A form where a user can select multiple beer sizes (to say that he’s interested in ALL of those sizes) might look like this:

<form method=POST
 action="SelectBeer.do">
 Select beer characteristics<p>
 Can Sizes: <p>
 <input type=checkbox name=sizes value="12oz"> 12 oz.<br>
 <input type=checkbox name=sizes value="16oz"> 16 oz.<br>
 <input type=checkbox name=sizes value="22oz"> 22 oz.<br>
 <br><br>

 <center>
   <input type="SUBMIT">
 </center>
</form>

In your code, you’ll use the getParameterValues() method that returns an ...