Java 创建过滤器 解析xml文件

package accp.com.xh.utils;
import java.io.IOException;
import java.io.InputStream;
import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.NodeList;
/**
 * 创建过滤器 
 * 前端控制器 接收所有参数；设置编码的格式；做登陆的控制拦截；分发请求
 * @author xiaohua
 *
 */
public class ActionFilter implements Filter{

    /**
     * tomcat启动时执行，只会执行一次;
     * 解析配置的规则文件 ：actions.xml
     */
    @Override
    public void init(FilterConfig config) throws ServletException {
        try {
            //得到action.xml文件
            InputStream is = Thread.currentThread().getContextClassLoader()
                    .getResourceAsStream("actions.xml");
            //解析xml文件
            Document document = DocumentBuilderFactory.newInstance()
                    .newDocumentBuilder().parse(is);
            //获取action标签元素：<action name="pro_.*" class="XXXXXAction">
            NodeList nodeList = document.getElementsByTagName("action");
            for(int i = 0 ;i<nodeList.getLength();i++){
                //解析action标签元素
                Element actionElement = (Element)nodeList.item(i);
                String actionName = actionElement.getAttribute("name");
                String actionClass = actionElement.getAttribute("class");
                System.out.println("actionName属性："+actionName);
                System.out.println("actionClass属性："+actionClass);
                //获取result 标签元素
                //<result name="reload" type="redirect">product</result>
                NodeList resultList = actionElement.getElementsByTagName("result");
                for(int j=0;j<resultList.getLength();j++){
                    Element resultEl =(Element) resultList.item(j);
                    String resultName = resultEl.getAttribute("name");//得到action.xml中的result name属性
                    String resultType = resultEl.getAttribute("type");
                    System.out.println("name属性："+resultName);
                    System.out.println("type属性："+resultType);
                }
                

            }
        } catch (Exception e) {
            throw new RuntimeException("解析action.xml文件出错："+e.getMessage());
        }
    }
    
    /**
     * 每次请求都会执行的过滤器 ；
     * 根据请求的URL 找出对应处理的XXXaction，判断哪个方法处理
     */
    @Override
    public void doFilter(ServletRequest request, ServletResponse response,
            FilterChain chain) throws IOException, ServletException {
        HttpServletRequest req =(HttpServletRequest)request;
        HttpServletResponse resp = (HttpServletResponse)response;
//        resp.sendRedirect("");
    }

    /**
     * 正常停止tomcat的时候执行，只会执行一次;
     * 销毁资源的操作，
     */
    @Override
    public void destroy() {
        
    }


}

<?xml version="1.0" encoding="UTF-8"?>
<!-- 定义业务规则 -->
<actions>
    <action name="pro_.*" class="XXXXXAction">
        <result name="list">/WEB-INF/view/list.jsp</result>
        <result name="edit" type="redirect">/WEB-INF/view/edit.jsp</result>
        <result name="reload" type="redirect">product</result>
    </action>
</actions>