求教struts2的文件下载问题？
在网上看了好多关于struts2的文件下载代码，自己试了一下，现在出现类型转换问题求教哪位高手帮解决一下。谢谢
我用的框架是SSI框架

代码如下：
DownloadAction.java

Java code

package com.test.action;import java.io.InputStream;import com.opensymphony.xwork2.ActionSupport;public class DownloadAction extends ActionSupport {    public InputStream getTargetFile() throws Exception {        return new java.io.FileInputStream("F:\\222.doc");    }    public String execute() throws Exception {        return SUCCESS;    }}

struts.xml

XML code

<?xml version="1.0" encoding="UTF-8" ?><!DOCTYPE struts PUBLIC         "-//Apache Software Foundation//DTD Struts Configuration 2.1//EN"         "http://struts.apache.org/dtds/struts-2.1.dtd"><struts>    <!--     <constant name="struts.enable.DynamicMethodInvocation" value="true" />     -->    <constant name="struts.custom.i18n.resources" value="messages"/>    <constant name="struts.i18n.encoding" value="GBK"/>    <constant name="struts.objectFactory" value="spring"></constant>    <package name="struct2" namespace="/" extends="struts-default">        <action name="download" class="downloadAction" method="getTargetFile">            <result name="success" type="stream">                <!--<param name="contentType">application/excel</param>-->                <param name="contentType">text/plain</param>                <param name="inputName">targetFile</param>                <param name="contentDisposition">attachment;filename="222.txt"</param>                <param name="bufferSize">4096</param>            </result>        </action>    </package>    <!-- Add packages here --></struts>

异常信息：java.io.FileInputStream cannot be cast to java.lang.String








[解决办法]
<param name="inputName">${targetFile}</param>

[解决办法]
文件输出流应该在execute方法里吧