struts2文件下载

strut.xml:

<action name="download" class="com.telewave.policesystemweb.szrk.DownloadAction" >
            <result name="success" type="stream">
<!-- 下载文件类型定义 -->
     <param name="contentType">application/octet-stream</param>
<!-- 下载文件输出流定义 -->
     <param name="inputName">inputStream</param>
　　　　　　　　　　　　　　　　　　<!-- 下载文件处理方式 -->
　　　　　　　　　　　　　　   　　<param name="contentDisposition">attachment;filename="${downfilename}"</param>   
     <!-- 下载文件的缓冲大小 -->
     <param name="bufferSize">4096</param>
</result>
        </action>

java代码（可见附件）：

package com.telewave.policesystemweb.szrk;
import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.InputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.apache.commons.lang.StringUtils;
import org.apache.struts2.ServletActionContext;

import com.opensymphony.xwork2.ActionSupport;
import com.sun.xml.messaging.saaj.packaging.mime.internet.MimeUtility;


/**
* 文件下载
* @author Luxh
*/
public class DownloadAction extends ActionSupport {


    private static final long serialVersionUID = -3036349171314867490L;
    
    //文件名
    private String fileName;
    private String downfilename;
    public String getFileName() {
        return fileName;
    }
public void setFileName(String fileName) throws UnsupportedEncodingException {
        //用UTF-8重新编码文件名,解决中文乱码
        this.fileName = fileName;
    }
    public String getDownfilename() {
return downfilename;
}
public void setDownfilename(String downfilename) {
this.downfilename = downfilename;
}    
public InputStream getInputStream() throws UnsupportedEncodingException, FileNotFoundException{
int i = fileName.lastIndexOf("\\");
String str = fileName.substring(i+1);//截取文件名
HttpServletRequest request = ServletActionContext.getRequest();
String userAgent = request.getHeader("User-Agent");
userAgent = userAgent.toLowerCase();
String filernd = "";
//针对不同浏览器，进行不同的编码，目前支持火狐、谷歌、ie
if (null != userAgent){ 
            if (-1 != userAgent.indexOf("firefox")) {//Firefox 
            filernd = "=?UTF-8?B?" + (new String(org.apache.commons.codec.binary.Base64.encodeBase64(str.getBytes("UTF-8"))))+ "?="; 
            }else if (-1 != userAgent.indexOf("chrome")) {//Chrome 
            filernd = new String(str.getBytes(), "ISO8859-1"); 
            } else {//IE7+ 
            filernd = java.net.URLEncoder.encode(str, "UTF-8"); 
            filernd = StringUtils.replace(filernd, "+", "%20");//替换空格 
            } 
        } else { 
        filernd = str; 
        }
setDownfilename(filernd);
//      IE浏览器可以用以下方式，不通过xml文件<param name="contentDisposition">attachment;filename="${downfilename}"</param>，但是非ie不支持以下这种方式，
// 只能通过xml文件方式读取action中的downfilename
// ServletActionContext.getResponse().setHeader(
// "Content-Disposition",
// "attachment;fileName="+filernd);
// + java.net.URLEncoder.encode(str, "ISO-8859-1"));
InputStream inputStream = new FileInputStream(fileName);
return inputStream;
 

    }  
    
    @Override
    public String execute() throws Exception {
        return SUCCESS;
    }


}