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Passing Static Array from JSP to Java Bean

Greenhorn

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posted 8 years ago

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This is for a class. After searching through many forums, I know that this isn't "ideal", but it is the assignment.

That said, I'm trying to pass an array from JSP to a Java Bean. When I call the Java Bean method from my JSP, the error it throws says "Cannot make a static reference to the non-static method setItems(String[]) from the type CatalogPage" (and another error for the title).

I understand that something has to be added to the java in order to accept the static info from the JSP, I'm just stuck on exactly how to do that. Any/all help is appreciated!

PhonePage.jsp

CatalogPage.java:

package shoppingCart;

import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
import item.CatalogItem;
import inventory.Catalog;
/** Base class for pages showing catalog entries.
 *  Servlets that extend this class must specify
 *  the catalog entries that they are selling and the page
 *  title <I>before</I> the servlet is ever accessed. This
 *  is done by putting calls to setItems and setTitle
 *  in init.
 *  <P>
 *  Taken from Core Servlets and JavaServer Pages 2nd Edition
 *  from Prentice Hall and Sun Microsystems Press,
 *  http://www.coreservlets.com/.
 *  © 2003 Marty Hall; may be freely used or adapted.
 */

public abstract class CatalogPage extends HttpServlet {
		
	  private CatalogItem[] items;
	  private String[] itemIDs;
	  private String title;
	
	  /** Given an array of item IDs, look them up in the
	   *  Catalog and put their corresponding CatalogItem entry
	   *  into the items array. The CatalogItem contains a short
	   *  description, a long description, and a price,
	   *  using the item ID as the unique key.
	   *  <P>
	   *  Servlets that extend CatalogPage <B>must</B> call
	   *  this method (usually from init) before the servlet
	   *  is accessed.
	   */

public void setItems(String[] itemIDs) {
	    this.itemIDs = itemIDs;
	    items = new CatalogItem[itemIDs.length];
	    for(int i=0; i<items.length; i++) {
	      items[i] = Catalog.getItem(itemIDs[i]);
	    }
	  }
	
	  /** Sets the page title, which is displayed in
	   *  an H1 heading in resultant page.
	   *  <P>
	   *  Servlets that extend CatalogPage <B>must</B> call
	   *  this method (usually from init) before the servlet
	   *  is accessed.
	   */
	  
	  public void setTitle(String title) {
	    this.title = title;
	  }
	
	  /** First display title, then, for each catalog item,
	   *  put its short description in a level-two (H2) heading
	   *  with the price in parentheses and long description
	   *  below. Below each entry, put an order button
	   *  that submits info to the OrderPage servlet for
	   *  the associated catalog entry.
	   *  <P>
	   *  To see the HTML that results from this method, do
	   *  "View Source" on KidsBooksPage or TechBooksPage, two
	   *  concrete classes that extend this abstract class.
	   */
	  
	  public void doGet(HttpServletRequest request,
	                    HttpServletResponse response)
	      throws ServletException, IOException {
	    if (items == null) {
	      response.sendError(response.SC_NOT_FOUND,
	                         "Missing Items.");
	      return;
	    }
	    response.setContentType("text/html");
	    PrintWriter out = response.getWriter();
	    String docType =
	      "<!DOCTYPE HTML PUBLIC \"-//W3C//DTD HTML 4.0 " +
	      "Transitional//EN\">\n";
	    out.println(docType +
	                "<HTML>\n" +
	                "<HEAD><TITLE>" + title + "</TITLE></HEAD>\n" +
	                "<BODY BGCOLOR=\"#FDF5E6\">\n" +
	                "<H1 ALIGN=\"CENTER\">" + title + "</H1>");
	    CatalogItem item;
	    for(int i=0; i<items.length; i++) {
	      out.println("<HR>");
	      item = items[i];
	      // Show error message if subclass lists item ID
	      // that's not in the catalog.
	      if (item == null) {
	        out.println("<FONT COLOR=\"RED\">" +
	                    "Unknown item ID " + itemIDs[i] +
	                    "</FONT>");
	      } else {
	        out.println();
	        String formURL =
	          "/csj/OrderPage";
	        // Pass URLs that reference own site through encodeURL.
	        formURL = response.encodeURL(formURL);
	        out.println
	          ("<FORM ACTION=\"" + formURL + "\">\n" +
	           "<INPUT TYPE=\"HIDDEN\" NAME=\"itemID\" " +
	           "       VALUE=\"" + item.getItemID() + "\">\n" +
	           "<H2>" + item.getShortDescription() +
	           " ($" + item.getCost() + ")</H2>\n" +
	           item.getLongDescription() + "\n" +
	           "<P>\n<CENTER>\n" +
	           "<INPUT TYPE=\"SUBMIT\" " +
	           "VALUE=\"Add to Shopping Cart\">\n" +
	           "</CENTER>\n<P>\n</FORM>");
	      }
	    }
	    out.println("<HR>\n</BODY></HTML>");
	  }
	}

Bear Bibeault

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posted 8 years ago

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Is it a bean or a servlet? It shouldn't be both. What's the resins for trying to make it a servlet?

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Bear Bibeault

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posted 8 years ago

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In any case, if you want to call methods from a static context, they need to be static themselves.

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Tony McManus

Greenhorn

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posted 8 years ago

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It is a bean, not a servlet. I'm not 'trying' to make it a servlet. The assignment was to convert a servlet into beans & jsps.

I know that I need to call methods from a static context. My point is: how do I do that? I need to take the values from the PhonePage.jsp and pass them to the CatalogPage.class. I know there probably has to be a way to define a method to do this, i just can't figure out how (and that's after 4 days of google searching, so clearly I'm either doing it wrong or I'm searching for the wrong stuff).

Bear Bibeault

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posted 8 years ago

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Well, it it's a bean it shouldn't be abstract or static in the first place, it should not extend HttpServlet, and shouldn't have any doXXX methods.

First step is to remove the servlet-ness from the class, make it non-abstract, and make sure it follows the bean pattern.

Next step, you'd instantiate an instance of the bean and you won;t have any static context to begin with.

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Campbell Ritchie

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Question too difficult for “beginning”. Moving discussion.

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