关于java类，转发jsp页面问题

package com;

import java.io.IOException;

import javax.servlet.jsp.PageContext;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;

public class LoadClass extends ClassLoader {
private DocumentBuilderFactory dbf;
private DocumentBuilder bd;
private Document doc;

/**
* 根据参数,查找xml返回结果
*/
private String getStr(String str) {
try {
// 加载xml方法
dbf = DocumentBuilderFactory.newInstance();
bd = dbf.newDocumentBuilder();
doc = bd.parse("struts-config.xml");
NodeList nl = doc.getElementsByTagName("action");
for (int i = 0; i < nl.getLength(); i++) {
Element ele = (Element) nl.item(i);
String tempname = ele.getAttribute("name");
if (str.equals(tempname)) {
return ele.getAttribute("class");
}
}
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}