How to access element attributes using JSP and XML?

[nathj]

Hi,

I'm trying to develop what should be a simple jsp that reads an XML file, parses it and displays the content in a web page. Simple right?

I have developed the XML and so any changes can be made there.

The XML IS

 
<?xml version="1.0" encoding="UTF-8"?>
<featured>
    <module type="Course Tool" title="Video Loader">
        <description>Do you want to deliver high quality vidoe to your class? This tool will enable you to load video content quickly and easily.</description>
        <img></img>
    </module>
    <module type="Course Tool" title="Content Block Loader">
        <description>Class content is more engaging when it is beautifully presented - use this tool to easily present the information in the most appealing manner possible.</description>
        <img></img>
    </module>
    <module type="Module" title="Art Gallery" priority="1">
        <description>Showcasing the best student artwork from across the foundation.</description>
        <img></img>
    </module>
    <module type="Module" title="Open Source">
        <description>Details on software that is free to use. Categorised to help you find the best application available.</description>
        <img></img>
    </module>
</featured>
 

The JSP that reads this uses a little Java class so here they are:

Java Class

package org.esf.utils;
 
import java.io.File;
 
import javax.servlet.jsp.JspWriter;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
 
import org.w3c.dom.Document;
import javax.xml.parsers.*;
import org.w3c.dom.*;
 
public class EsfDomParserBean implements java.io.Serializable
{
    public EsfDomParserBean()
    {
    }
 
    public static Document getDocument(String file) throws Exception
    {
 
        // Step 1: create a DocumentBuilderFactory
        DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
 
        // Step 2: create a DocumentBuilder
        DocumentBuilder db = dbf.newDocumentBuilder();
 
        // Step 3: parse the input file to get a Document object
        Document doc = db.parse(new File(file));
        return doc;
    }
}
 

The JSP

<div class="horizontalScroll" id="horizontalScroll" style="display:block;float:left;overflow:auto;overflow-x:scroll;overflow-y:hidden;height:250px">
    <%
        String esfXMLPath = blackboard.platform.plugin.PlugInUtil.getUri("ESFN", "Featured-Module", "FeaturedModule.xml");
        Document doc = EsfDomParserBean.getDocument(esfXMLPath);
        traverseTree(doc, out);
    %>
 
    <%!private void traverseTree(Node node, JspWriter out) throws Exception 
        {
            if (node == null) 
            {
                return;
            }
            int type = node.getNodeType();
            String itemTitle = "";
            switch (type) 
            {
                // handle document nodes
                case Node.DOCUMENT_NODE: 
                {
                    out.println("<div class=\"detailsContainer\" id=\"detailsContainer\" style=\"display:inline-block;float:left;\">");
                    traverseTree(((Document) node).getDocumentElement(), out);
                    break;
                }
                // handle element nodes
                case Node.ELEMENT_NODE: 
                {
                    String elementName = node.getNodeName();
 
                    if (elementName.equalsIgnoreCase("module")) 
                    {
                        Element e = (Element) node;
                        if(e.hasAttribute("type") && e.hasAttribute("title"))
                        {
                            itemTitle = "<h3>" + e.getAttribute("type") + " " + e.getAttribute("title") + "</h3>";
                        }
                        else
                        {
                            itemTitle = "<h3>Cannot find type or title</h3>";
                        }
                        out.println("</div><div class=\"detailsContainer\" id=\"detailsContainer\" style=\"display:inline-block;float:left;\">");
                    }
                    NodeList childNodes = node.getChildNodes();
                    if (childNodes != null) 
                    {
                        int length = childNodes.getLength();
                        for (int loopIndex = 0; loopIndex < length; loopIndex++) 
                        {
                            traverseTree(childNodes.item(loopIndex), out);
                        }
                    }
                    break;
                }
                // handle text nodes
                case Node.TEXT_NODE: 
                {
                    String data = node.getNodeValue().trim();
                    if ((data.indexOf("\n") < 0) && (data.length() > 0)) 
                    {
                        if(data.toUpperCase().contains(".jpg")||data.toUpperCase().contains(".jpeg")||data.toUpperCase().contains(".png"))
                        {
                            out.println("<span class=\"rightContainer\" id=\"rightContainer\" style=\"display:inline;float:right\"><img src=\"" + data + "\"/></span>");
                        }
                        else
                        {
 
                            out.println("<span class=\"leftContainer\" id=\"leftContainer\" style=\"display:inline;float:left\">" + itemTitle +  data + "</span>");
                        }
                    }
                }
            }
        }
%>
</div>
 

I need to get the type and title attributes out of the module element so that I can write them out in a <h3> tags inside the leftContainer span. The trouble is I can't find the way to retrieve this information. I've been reading around the web for a couple of days now and I'm not finding anything on this.

Does anyone have a great tip/pointer for me or even a tutorial where this has been done already?

Cheers
nathj

[nathj]

Hi,

Here's a quick update on the progress I'm making. As such the question has changed slightly now.

<%
    String esfXMLPath = blackboard.platform.plugin.PlugInUtil.getUri("ESFN", "Featured-Module", "FeaturedModule.xml");
    Document doc = EsfDomParserBean.getDocument(esfXMLPath);
    //traverseTree(doc, out);
    Element root = doc.getDocumentElement();
    NodeList moduleList = root.getChildNodes();
 
    StringBuilder output = new StringBuilder("<div class=\"horizontalScroll\" id=\"horizontalScroll\" style=\"display:block;float:left;overflow:auto;overflow-x:scroll;overflow-y:hidden;height:250px\">");
 
    for(int i = 0; i < moduleList.getLength(); i++)
    {
        Node module = moduleList.item(i);
        if(module.getNodeName().equals("module"))
        {
            output.append("<div class=\"detailsContainer\" id=\"detailsContainer\" style=\"display:inline-block;float:left;\">");
            Element section = (Element) moduleList.item(i);
            String title= "<h3>" + section.getAttribute("type") + "&nbsp;&mdash;&nbsp;" + section.getAttribute("title") + "</h3>";
 
            NodeList moduleDetails = module.getChildNodes();
            for(int j = 0; j < moduleDetails.getLength(); j++)
            {
                Node moduleDetail = moduleDetails.item(j);
                if(moduleDetail.getNodeName().equalsIgnoreCase("description"))
                {
                    output.append("<span class=\"leftContainer\" id=\"leftContainer\" style=\"display:inline;float:left\">" + title + moduleDetail.getNodeValue() + "</span>");
                }
                if(moduleDetail.getNodeName().equalsIgnoreCase("img"))
                {
                    output.append("<span class=\"rightContainer\" id=\"rightContainer\" style=\"display:inline;float:right\"><img src=\"" + moduleDetail.getNodeValue() + "\"/></span>");
                }
            }
            output.append("</div>");
        }
    }
    output.append("</div>");
%>
<%=output.toString() %>
 

Now I'm getting the type and title out of the module element which is great. The trouble is that I now am not getting the data out of the XML, so I'm not seeing the description coming out.

Any help on this is greatly appreciated.

Cheers
nathj

[nathj]

Hi,

A little bit of perseverance and some playing around I have it cracked.

<%
    String esfXMLPath = blackboard.platform.plugin.PlugInUtil.getUri("ESFN", "Featured-Module", "FeaturedModule.xml");
    Document doc = EsfDomParserBean.getDocument(esfXMLPath);
    //traverseTree(doc, out);
    Element root = doc.getDocumentElement();
    NodeList moduleList = root.getChildNodes();
 
    StringBuilder output = new StringBuilder("<div class=\"horizontalScroll\" id=\"horizontalScroll\" style=\"display:block;float:left;overflow:auto;overflow-x:scroll;overflow-y:hidden;height:250px\">");
 
    for(int i = 0; i < moduleList.getLength(); i++)
    {
        Node module = moduleList.item(i);
        if(module.getNodeName().equals("module"))
        {
            output.append("<div class=\"detailsContainer\" id=\"detailsContainer\" style=\"display:inline-block;float:left;\">");
            Element section = (Element) moduleList.item(i);
            String title= "<h3>" + section.getAttribute("type") + "&nbsp;&mdash;&nbsp;" + section.getAttribute("title") + "</h3>";
 
            NodeList moduleDetails = module.getChildNodes();
            for(int j = 0; j < moduleDetails.getLength(); j++)
            {
                Node moduleDetail = moduleDetails.item(j);
                if(moduleDetail.getNodeName().equalsIgnoreCase("description"))
                {
                    output.append("<span class=\"leftContainer\" id=\"leftContainer\" style=\"display:inline;float:left\">" + title + "<p>" + moduleDetail.getChildNodes().item(0).getNodeValue() + "</p></span>");
                }
                if(moduleDetail.getNodeName().equalsIgnoreCase("img"))
                {
                    output.append("<span class=\"rightContainer\" id=\"rightContainer\" style=\"display:inline;float:right\"><img src=\"" + moduleDetail.getChildNodes().item(0).getNodeValue() + "\"/></span>");
                }
            }
            output.append("</div>");
        }
    }
    output.append("</div>");
%>
<%=output.toString() %>
 

I admit I need some error trapping in here - particularly to cater for NullPointerExceptions but the basics are there thanks to :
http://groups.google.com/group/Googl...d9b39322?pli=1
http://www.java2s.com/Code/JavaAPI/o...tNodeValue.htm

Thanks
nathj