web.xml 同时配置Struts2与Servlet的解决方法

* 该类是定义了一个过滤器（随便你放在摸个包下面），当既用到struts2有用到servlet时，
* 必须用该过滤器对所有的servlet做一次过滤，否则servlet将无法正常运行。
* 同时在web.xml中，在定义struts的核心控制器前面添加该过滤器，添加代码如下：
* <filter>
*   <filter-name>redisp</filter-name>
*   <filter-class>filters.ReDispatcherFilter（该过滤器的类名）</filter-class>
*   <init-param>
*    <param-name>includeServlets</param-name>
*    <param-value>所配置的servlet，注意是那url-pattern</param-value>
*   </init-param>
* </filter>
* <filter-mapping>
*   <filter-name>redisp</filter-name>
*   <url-pattern>/*</url-pattern>
* </filter-mapping>
* @author xsl
*
*/

ReDispatcherFilter的完整代码为:

package zy.page.demo.servletconf;

import java.io.IOException;
import java.util.ArrayList;
import java.util.Arrays;

import javax.servlet.Filter;
import javax.servlet.FilterChain;
import javax.servlet.FilterConfig;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.ServletRequest;
import javax.servlet.ServletResponse;
import javax.servlet.http.HttpServletRequest;

public class ReDispatcherFilter implements Filter {

	public void destroy() {
		// TODO Auto-generated method stub

	}

	public void doFilter(ServletRequest req, ServletResponse resp,
			FilterChain chain) throws IOException, ServletException {

		HttpServletRequest request = (HttpServletRequest) req;
		String target = request.getRequestURI();
		target = target.lastIndexOf("?") > 0 ? target.substring(target
				.lastIndexOf("/") + 1, target.lastIndexOf("?")
				- target.lastIndexOf("/")) : target.substring(target
				.lastIndexOf("/") + 1);

		System.out.println(target);
		if (this.includes.contains(target)) {
			RequestDispatcher rdsp = request.getRequestDispatcher(target);

			System.out.println("go..............." + rdsp);
			rdsp.forward(req, resp);
		} else
			chain.doFilter(req, resp);
	}

	private ArrayList<String> includes = new ArrayList<String>();

	public void init(FilterConfig config) throws ServletException {

		this.includes.addAll(Arrays.asList(config.getInitParameter(
				"includeServlets").split(",")));

	}

}

web.xml做的配置为(可参照第一段内容的说明配置拦截器)：

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://java.sun.com/xml/ns/javaee 
	http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
	<welcome-file-list>
		<welcome-file>./page/showpage.jsp</welcome-file>
	</welcome-file-list>
	<filter>
		<filter-name>redisp</filter-name>
		<filter-class>zy.page.demo.servletconf.ReDispatcherFilter</filter-class>
		<init-param>
			<param-name>includeServlets</param-name>
			<param-value>downexcel</param-value>
		</init-param>
	</filter>
	<filter-mapping>
		<filter-name>redisp</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>
	<servlet>
		<description>This is the description of my J2EE component</description>
		<display-name>This is the display name of my J2EE component</display-name>
		<servlet-name>downexcel</servlet-name>
		<servlet-class>zy.demo.test.DownExcel</servlet-class>
	</servlet>

	<servlet-mapping>
		<servlet-name>downexcel</servlet-name>
		<url-pattern>/downexcel</url-pattern>
	</servlet-mapping>
	<filter>
		<filter-name>struts2</filter-name>
		<filter-class>org.apache.struts2.dispatcher.ng.filter.StrutsPrepareAndExecuteFilter</filter-class>
	</filter>
	<!-- 让Struts 2的核心Filter拦截所有请求 -->
	<filter-mapping>
		<filter-name>struts2</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>

	<!--
		<servlet> <servlet-name>Readxml</servlet-name>
		<servlet-class>zy.demo.utils.Readxml</servlet-class>
		<load-on-startup>1</load-on-startup> </servlet>
	-->
</web-app>

注意：拦截器的配置要放在servlet配置的前面，否则无效。实测成功！