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Reading an XML file in WEB-INF with Bean

Posted on 2010-11-14
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Last Modified: 2012-05-10
Hi there experts,

i have a short question:
I'm currently writing my own Web Application with Java and this Webapplication has its own configuration xml files. These files are under the WEB-INF folder, so only the Servlet or JSP can access it.
Now i want to write a Java Bean that reads this config-files and provides some getter functions...
The reason, why i want to write a bean is, because this config files should be accessed by many servlets and some JSPs.

How can i access the config files with a java bean?
and what would be the best way to parse the XMLs?


thx for your help and best regards!
manuel
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Comment
Question by:mesX
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6 Comments
 
LVL 27

Expert Comment

by:rrz
ID: 34132880
Please read
previous discussion  
We can help you with anyway you want to go with this.
JSTL is the easy way to go.  
0
 

Author Comment

by:mesX
ID: 34134259
Hi and thx for your comment!
As i understand JSTL is only for JSP pages, isn't it?
... and i can't use it within a Java Bean?

Or is my understanding of a Java Bean wrong?
What i want to do is, that my Servlets and JSPs create an Object from my "ApplicationConfig" class which parses the XML and has some getter functions like "String[] getAllEmployeeNames()". So if i change the XML file one day, i just have to re-write my ApplicationConfig class.

Please correct me if my idea is not a good one, because i'm very new to all this :)

regards
Manuel
0
 
LVL 27

Accepted Solution

by:
rrz earned 500 total points
ID: 34138005
To get started, try this code.
The file employees.xml contains  
<?xml version="1.0"?>
<company>
	<employee>
		<firstname>John</firstname>
		<lastname>Smith</lastname>
	</employee>
	<employee>
		<firstname>Jane</firstname>
		<lastname>Doe</lastname>
	</employee>
	<employee>
		<firstname>Jerry</firstname>
		<lastname>Brown</lastname>
	</employee>
</company>

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put that xml file into your web app's classes folder.

Create a JSP containing  
<jsp:useBean id="reader" class="rrz.XMLReader" />
<%=reader.read()%>

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This is just quick and dirty demo code. We should create getter and setter methods for fields in your bean.
Show us an example of your XML and tell us what you want to access, if you want more help.

package rrz;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
public class XMLReader {
  public String read(){
      StringBuilder sb = new StringBuilder();
      try {
           DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
           DocumentBuilder db = dbf.newDocumentBuilder();
           Document doc = db.parse(getClass().getClassLoader().getResourceAsStream("employees.xml"));
           doc.getDocumentElement().normalize();
           sb.append("Root element " + doc.getDocumentElement().getNodeName() + "<br/>");
           NodeList nodeLst = doc.getElementsByTagName("employee");
           sb.append("Information of all employees" + "<br/>");
           for (int s = 0; s < nodeLst.getLength(); s++) {
              Node fstNode = nodeLst.item(s);
              if (fstNode.getNodeType() == Node.ELEMENT_NODE) {
                 Element fstElmnt = (Element) fstNode;
                 NodeList fstNmElmntLst = fstElmnt.getElementsByTagName("firstname");
                 Element fstNmElmnt = (Element) fstNmElmntLst.item(0);
                 NodeList fstNm = fstNmElmnt.getChildNodes();
                 sb.append("First Name : "  + ((Node) fstNm.item(0)).getNodeValue() + "<br/>");
                 NodeList lstNmElmntLst = fstElmnt.getElementsByTagName("lastname");
                 Element lstNmElmnt = (Element) lstNmElmntLst.item(0);
                 NodeList lstNm = lstNmElmnt.getChildNodes();
                 sb.append("Last Name : " + ((Node) lstNm.item(0)).getNodeValue() + "<br/>");
              }
           }
      } catch (Exception e) {
                             e.printStackTrace();
        }
      return sb.toString();
  }
}

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Author Comment

by:mesX
ID: 34138573
You're absolutely awesome!!!! THANK YOU VERY MUCH!

I just have a very small question:
What if i put the employee.xml directly under the WEB-INF folder? Or in my case /WEB-INF/configs/employee.xml? How can i access files inside the WEB-INF folder but outside the classes folder?


best regards
Manuel
0
 
LVL 27

Assisted Solution

by:rrz
rrz earned 500 total points
ID: 34138969
>How can i access files inside the WEB-INF folder but outside the classes folder?  
There are several ways. One simple way is pass the path from JSP to bean.
<jsp:useBean id="reader" class="rrz.XMLReader" />
<%
  String path = application.getRealPath("/WEB-INF/configs/employees.xml");
  reader.setPath(path);
%>
<%=reader.read()%>

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and in source code  
File file = new File(path);
           DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
           DocumentBuilder db = dbf.newDocumentBuilder();
           Document doc = db.parse(file);

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Better to solution at  previous discussion
0
 

Author Closing Comment

by:mesX
ID: 34139232
Thank you so much for all your help! You're a truly expert ;)

I hope you can help me in my future questions too (and i will surely have many  ;) )

best regards
Manuel
0

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