Question

BACKGROUND

I am learning Java and currently on JSF. I come from an ASP.NET MVC background and have only recently been exposed to the Java world, so be gentle 😉

PROBLEM

I can’t quite figure out how to get a model (which is of List<T>) into the JSF view. What I did when recently learning Struts was the following:

1. Created a Servlet like this:

   @WebServlet(name = "ViewProductsServlet", urlPatterns = {"/ViewProductsServlet"})

   public class ViewProductsServlet extends HttpServlet {

       protected void processRequest(HttpServletRequest request, HttpServletResponse response)
               throws ServletException, IOException {
   
           ProductRepository repository = new ProductRepository();
           List<Product> model = repository.getAll();
           request.setAttribute("model", model);
           request.getRequestDispatcher("/viewProducts.jsp").forward(request, response);
       }
   

2. Linked to the view products page like this:

<html:link forward="viewProducts" styleClass="btn btn-primary">View Products</html:link>

1. In the view, I got the model like this:

   <%
List<Product> model = (List<Product>)request.getAttribute("model");
%>

and then I just iterated over the items with JSTL tags.. not sure if that was the “correct” way to do it, but it worked..

Now for the JSF stuff, I am trying to take a similar approach but I noticed that the <% %> tags don’t work in xhtml pages. Fair enough, but then how do I pass a collection to a page so I can display the items in a table/grid?

EDIT

Thanks to Sanjeevi.V, I can see that I am supposed to use the h:dataTable tag. However, it is not displaying data. Here is my code:

MODEL/Manage Bean:

@ManagedBean
@SessionScoped
public class EmployeeCollection {
    private List<Employee> items;

    public List<Employee> getItems() {
        if (items == null) {
            EmployeeRepository repository = new EmployeeRepository();
            items = repository.getAll();
        }

        return items;
    }
}

View Markup:

<div class="container-fluid">
            <div class="row-fluid">
                <div class="span8 offset2">
                    <h:dataTable class="table table-striped" value="#{EmployeeCollection.items}" var="item">
                        <h:column>
                            <f:facet name="header">First Name</f:facet>
                            #{item.getFirstName()}
                        </h:column>
                        <h:column>
                            <f:facet name="header">Last Name</f:facet>
                            #{item.getLastName()}
                        </h:column>
                        <h:column>
                            <f:facet name="header">Date of Birth</f:facet>
                            #{item.getDateOfBirth().toString()}
                        </h:column>
                    </h:dataTable>
                </div>
            </div>
        </div>

I tried to follow that tutorial, so I’m not sure where I am going wrong. Personally, I don’t understand how it could work.. how does the EmployeeCollection bean get wired up? Is it because it’s got @SessionScoped that there is only ever one per session and so will use that? Even so, at the time of running, it would be a null object. What am I missing here? How can I make this work? I do indeed have rows in the database, so don’t ask about that. 🙂

Answer 1

Try the following code,

Managed Bean:

@ManagedBean(name = "bean")
@SessionScoped
public class Bean {
private List<Integer> numList;

public List<Integer> getNumList() {
    return numList;
}

public void setNumList(List<Integer> numList) {
    this.numList = numList;
}

public Bean() {
    numList=new ArrayList<Integer>();
    for (int i = 0; i < 10; i++) {
        numList.add((int)(Math.random()*100));
    }
}

}

Markup:

<h:dataTable value="#{bean.numList}" var="num">
  <h:column><h:outputText value="#{num}"/></h:column>
</h:dataTable>

source : http://www.mkyong.com/jsf2/jsf-2-datatable-example/

Hope this helps.