JSP tag to use to call servlet

[chure abcede]

Hi guys,

I've already read bunch of tutorials about jsp and servlet and I'm already aware of not using a scriplet inside a jsp. My problem is that i'm still confuse of the different tags and I don't know yet much of the functionality of the different tags.What tag would be use if I will call a servlet inside Jsp where that servlet is just simply execute something behind the scene, ie. not returning any variable.. , for example is Connection in Database.

Thanks

[Bear Bibeault]

You would not call the servlet from the JSP. Any preparation needed by the page would be handled in the servlet controller before the servlet forwards to the JSP.

[chure abcede]

oh I see. I thought we could just easily call and run a servlet in Jsp line with a Tag. So Sir Beau,if that's the case, what tag should I use or the preparation. Are you referring for the JavaBeans tag and setAttributes place inside servlet and forward the response to JSP?[based on BeerSelect.java :). I tried it but I guess its only applicable if your passing a variable from a servlet to JSP.

[Bear Bibeault]

chure abcede wrote:I thought we could just easily call and run a servlet in Jsp line with a Tag.

You actually can -- the <jsp:include> action can call any resource. It's just not considered a good practice. Common practice is to handle all data activity in the controller and to keep the JSP as "dumb" as possible.

what tag should I use or the preparation.

Again, no tag. Any data activity that needs to be performed should be done before the JSP gets invoked. Have you read this article which describes page controllers?

setAttributes place inside servlet and forward the response to JSP?

Pretty much. The controller does the data access, places the data into request scope, and the request is forwarded to the JSP which accesses the values via the EL and JSTL.

I tried it but I guess its only applicable if your passing a variable from a servlet to JSP.

What do mean by "only applicable"? This is always applicable when using accepted practices.

[chure abcede]

What do mean by "only applicable"? This is always applicable when using accepted practices.

I mean, in the code below:BeerExpert.java

                PrintWriter out= response.getWriter();
		BeerExpert BExpert= new BeerExpert();
		RequestDispatcher view;
		List result;
		String color;
		
		color=request.getParameter("color");
		result= BExpert.getBrands(color);
		
		request.setAttribute("styles", result); ---->Im referring to this line, since it it passing a variable List type.
		
		view= request.getRequestDispatcher("/WEB-INF/result.jsp");
		view.forward(request, response);

JSP-result.jsp

<%
	List styles = (List)request.getAttribute("styles"); ------->Initializing the variable that has been passed.
	Iterator it= styles.iterator();
	while(it.hasNext()){
		out.print("<br>try: " + it.next());
	}
%>

Im wondering if, I could revise this code and just execute a bunch of codes inside the servlet and not passing a variable.

[Bear Bibeault]

Why?

Are you not interested in following accepted best practices? Why would you want make it many times more messy than necessary, and therefore more confusing and fragile?

And, of course, you should modernize the JSP to use JSTL and EL, and not obsolete scriptlets.

[chure abcede]

Oh.. I see.. there is a misunderstanding. : ) . I'm referring about the use of setAttribute, hence it is passing a variable object. Of course sir Beau, I would love to follow the best practices and also consider learning JSTL and EL. I'm still reading the tutorial you've shared to me. It's a great book maybe its just me who can't catch up easily in JSP :(.

[Bear Bibeault]

What is your beef with using setAttribute()? It's the way that scoped variables are created to send data from the controller to the page.