How to link different URLs to different items in forEach loop in JSP page?

Question

I have a facultylist.jsp page which displays List<Faculty> as a request attribute parameter in forEach loop and I want every item in this loop to be a link to specified faculty facultyview.jsp. How can I achieve that ?

facultylist.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Faculties</title>
</head>
<body>
<h1>Faculties list</h1>
    <ul>
        <c:forEach var="faculty" items="${faculties}">
            <li><a href="???">${faculty.name}</a></li>
        </c:forEach>
    </ul>
</body>
</html>

facultyview.jsp:

<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>Faculty</title>
</head>
<body>
    <h1>${faculty.name}</h1>
    <ul>
        <li>Faculty name: <c:out value="${requestScope.name}"></c:out></li>
        <li>Total seats: <c:out value="${requestScope.total_seats}"></c:out></li>
        <li>Budget seats: <c:out value="${requestScope.budget_seats}"></c:out></li>
    </ul>
    <a href="faculty?apply">apply for this faculty </a>
</body>
</html>

I don't know if its may help, but I'm using following technologies: tomcat, jsp, servlets and log4j.In my project I have one FrontController, which is a servlet that interacts with Command pattern - each Command returns a path to resource and action type: forward or redirect.

Are the URLs really different, or can you have the same URL and have the faculty as a parameter concatenated to the URL? — Ofer Lando, Jan 20 '15 at 09:07
are you trying to pass list of faculty.links like names and use smth like `
@JordiCastilla faculty represents an entity from database, i'm not sure if I want to change it adding another field, or you mean some other way ? — marknorkin, Jan 20 '15 at 09:11
@Jango but `${faculty.url}` means that I have a field in faculty, which is not true — marknorkin, Jan 20 '15 at 09:12
check my answer's edit, but since i'm not sure how you get the URL's, I can't help more... — Jordi Castilla, Jan 20 '15 at 09:17

Master Slave · Accepted Answer · 2015-01-20T09:56:29.820

1

You can solve your issue by adding a query params to the link, edit with respect to the comment. Note that you cannot access directly the JSP pages that reside under WEB-INF folder. Also, to encode properly the paramters, better construct url like

<c:url value="facultyview.jsp" var="url">
  <c:param name="name" value="${faculty.name}"/>
  <c:param name="total_seats" value="${faculty.total_seats}"/>
  <c:param name="budget_seats" value="${faculty.budget_seats}"/>
</c:url>
<li><a href="${url}">${faculty.name}</a></li>

and than than in your facultyview.jsp read from the query params

<li>Faculty name: ${param.name}</li>
<li>Total seats: ${param.total_seats}</li>
<li>Budget seats:${param.budget_seats}</li>

This direct JSP communication should solve your immediate issue, but a truly proper way would be to pass an id of a faculty to servlet, fetch the faculty instance, place in the model and pass to the view.

edited Jan 20 '15 at 09:56

answered Jan 20 '15 at 09:17

Master Slave

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i have tried your solution, but I get the `HTTP Status 404 Error`. The URL that I'm forwarding is as example: `http://localhost:8080/WEB-INF/view/client/faculty/view.jsp?name=faculty of applied mathematics&total_seats=20&budget_seats=10` – marknorkin Jan 20 '15 at 09:46
I've edited the response, the main issue is that you can't directly access a page under /WEB-INF so you'll either have to move the jsp, or forward to it – Master Slave Jan 20 '15 at 09:58
oh thank you for practice advice! but as I know for now the only way to get info from servlet is to use
tags. And they are not working with `
` tags as I know. So my question is should I replace in `facultyview.jsp` `
` tags with `` and use it like: `
` or there is another way ?
– marknorkin Jan 20 '15 at 10:08
is this approach the same ? ` ` – marknorkin Jan 20 '15 at 10:34
1

no need for form, the link inside your a tag can hit a servlet e.g. http://stackoverflow.com/questions/1907482/call-a-servlet-on-click-of-hyperlink, and from the servlet, its perfectly OK to forward to a jsp page that resides in WEB-INF, e.g. http://stackoverflow.com/questions/22928427/how-to-redirect-to-jsp-inside-web-inf-folder. The work inside your servlet is to collect the parameters, and either append them when forwarding to jsp, or adding them into a request scope, in which case your original facultyview page will work well also – Master Slave Jan 20 '15 at 10:34
regarding forward, you can't do jsp forward when clicking on a link, so either use servlets, or place your jsp outside of WEB-INF folder so that it can be accessed directly (via link) – Master Slave Jan 20 '15 at 10:37
Let us [continue this discussion in chat](http://chat.stackoverflow.com/rooms/69197/discussion-between-mark-and-master-slave). – marknorkin Jan 20 '15 at 10:42

Jordi Castilla · Answer 2 · 2015-01-20T10:17:35.503

0

If you have a field in Faculty entity simply:

<a href="${faculty.url}">${faculty.name}</a>

@Mark: faculty represents an entity from database, i'm not sure if I want to change it adding another field, or you mean some other way ?

Add a field does not means you must change database, you can have a Helper entity that inherits from Faculty and have more fields you can need,

public class FacultyFormHelper extends Faculty implements Serializable {

    private String URL;

and in your view:

<a href="${facultyHelper.url}">${facultyHelper.name}</a>

But, If you don't want to modify your database, either create a helper class, you may add onclick event to the <a>

<a onclick="goToURL(${faculty.id})">

Then retrieve the data... i'm not sure how you get the urls... from a variable in the view, ajax call or wherever you have this URL...

edited Jan 20 '15 at 10:17

answered Jan 20 '15 at 09:09

Jordi Castilla

26,609
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thanks for suggestion. I'm a starter, so may I ask you for the future if this is a good practice to extend entity functionality in children and use them in jsp's ? – marknorkin Jan 20 '15 at 09:50
As far as I know (I'm not an expert either) it is a good and usual practice, Also you must check how to implement an entity populator or use a framework like `dozer` to manage your database / model / view entities... – Jordi Castilla Jan 20 '15 at 10:08

score 0 · Answer 3 · answered Jan 20 '15 at 09:09

in other way is just take the selected value from the drop down with a name and forward it to front controller servlet ,there use if else conditions and depends on the value you could forward the request to corresponding jsp or servlet

<select name="value"> in jsp 

String value=req.getParameter("value");   in servlet

if()
else if()

How to link different URLs to different items in forEach loop in JSP page?

3 Answers3