Struts2文件下载

一个简单的利用struts2做文件下载的demo……

首先配好struts：

web.xml

1. <?xml version="1.0" encoding="UTF-8"?>
2. <web-app version="2.4"
3.         xmlns= "http://java.sun.com/xml/ns/j2ee"
4.         xmlns:xsi= "http://www.w3.org/2001/XMLSchema-instance"
5.         xsi:schemaLocation= "http://java.sun.com/xml/ns/j2ee
6.         http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" >
7.   <welcome-file-list>
8.     <welcome-file>index.jsp </welcome-file>
9.   </welcome-file-list>
10.  
11.   <filter>
12.         <filter-name>struts2 </filter-name>
13.         <filter-class>org.apache.struts2.dispatcher.FilterDispatcher </filter-class>
14.   </filter>
15.   <filter-mapping>
16.         <filter-name>struts2 </filter-name>
17.         <url-pattern>/* </url-pattern>
18.   </filter-mapping>
19.  
20. </web-app>

struts.xml——这里是重点

1. <!DOCTYPE struts PUBLIC
2.          "-//Apache Software Foundation//DTD Struts Configuration 2.0//EN"
3.          "http://struts.apache.org/dtds/struts-2.0.dtd">
4.   <struts>
5.       <package name="default" extends="struts-default">
6.          <action name="download" class="action.DownloadAction">
7.             <result type="stream">
8.                                 <param name="contentType">application/octet-stream </param>
9.                                 <param name="inputName">inputStream </param>
10.                                 <param name="contentDisposition">attachment;filename="${fileName}" </param>
11.                                 <param name="bufferSize">4096 </param>
12.             </result>
13.          </action>
14.       </package>
15.   </struts>

当result为stream类型时，struts2会自动根据你配置好的参数下载文件。

其中主要使用的参数是：
contentType 指定下载文件的文件类型 —— application/octet-stream 表示无限制
inputName 流对象名 —— 比如这里写inputStream，它就会自动去找Action中的getInputStream方法。
contentDisposition 使用经过转码的文件名作为下载文件名 —— 默认格式是attachment;filename="${fileName}"，将调用该Action中的getFileName方法。
bufferSize 下载文件的缓冲大小

之后写个DownloadAction：

1. package action;
2.  
3. import java.io.InputStream;
4.  
5. import org.apache.struts2.ServletActionContext;
6.  
7. public class DownloadAction {
8.        
9.         private String fileName;
10.        
11.         public void setFileName ( String fileName ) {
12.                 this. fileName = fileName;
13.         }
14.         public InputStream getInputStream ( ) {
15.                 return ServletActionContext. getServletContext ( ). getResourceAsStream ( "/" + fileName );
16.         }
17.        
18.         public String execute ( ) {
19.                 return "success";
20.         }
21.  
22. }

* 注意使用getResourceAsStream方法时，文件路径必须是以“/”开头，且是相对路径。这个路径是相对于项目根目录的。
* 可以用return new FileInputStream(fileName)的方法来得到绝对路径的文件。

在WEB-INF下随意丢一个test.txt，部署好后进入浏览器，输入tomcat地址/项目路径/download.action?fileName=test.txt即可下载到该文件。

附:contentType类型.
'ez' => 'application/andrew-inset',
'hqx' => 'application/mac-binhex40',
'cpt' => 'application/mac-compactpro',
'doc' => 'application/msword',
'bin' => 'application/octet-stream',
'dms' => 'application/octet-stream',
'lha' => 'application/octet-stream',
'lzh' => 'application/octet-stream',
'exe' => 'application/octet-stream',
'class' => 'application/octet-stream',
'so' => 'application/octet-stream',
'dll' => 'application/octet-stream',
'oda' => 'application/oda',
'pdf' => 'application/pdf',
'ai' => 'application/postscript',
'eps' => 'application/postscript',
'ps' => 'application/postscript',
'smi' => 'application/smil',
'smil' => 'application/smil',
'mif' => 'application/vnd.mif',
'xls' => 'application/vnd.ms-excel',
'ppt' => 'application/vnd.ms-powerpoint',
'wbxml' => 'application/vnd.wap.wbxml',
'wmlc' => 'application/vnd.wap.wmlc',
'wmlsc' => 'application/vnd.wap.wmlscriptc',
'bcpio' => 'application/x-bcpio',
'vcd' => 'application/x-cdlink',
'pgn' => 'application/x-chess-pgn',
'cpio' => 'application/x-cpio',
'csh' => 'application/x-csh',
'dcr' => 'application/x-director',
'dir' => 'application/x-director',
'dxr' => 'application/x-director',
'dvi' => 'application/x-dvi',
'spl' => 'application/x-futuresplash',
'gtar' => 'application/x-gtar',
'hdf' => 'application/x-hdf',
'js' => 'application/x-javas

cript',
'skp' => 'application/x-koan',
'skd' => 'application/x-koan',
'skt' => 'application/x-koan',
'skm' => 'application/x-koan',
'latex' => 'application/x-latex',
'nc' => 'application/x-netcdf',
'cdf' => 'application/x-netcdf',
'sh' => 'application/x-sh',
'shar' => 'application/x-shar',
'swf' => 'application/x-shockwave-flash',
'sit' => 'application/x-stuffit',
'sv4cpio' => 'application/x-sv4cpio',
'sv4crc' => 'application/x-sv4crc',
'tar' => 'application/x-tar',
'tcl' => 'application/x-tcl',
'tex' => 'application/x-tex',
'texinfo' => 'application/x-texinfo',
'texi' => 'application/x-texinfo',
't' => 'application/x-troff',
'tr' => 'application/x-troff',
'roff' => 'application/x-troff',
'man' => 'application/x-troff-man',
'me' => 'application/x-troff-me',
'ms' => 'application/x-troff-ms',
'ustar' => 'application/x-ustar',
'src' => 'application/x-wais-source',
'xhtml' => 'application/xhtml+xml',
'xht' => 'application/xhtml+xml',
'zip' => 'application/zip',
'au' => 'audio/basic',
'snd' => 'audio/basic',
'mid' => 'audio/midi',
'midi' => 'audio/midi',
'kar' => 'audio/midi',
'mpga' => 'audio/mpeg',
'mp2' => 'audio/mpeg',
'mp3' => 'audio/mpeg',
'aif' => 'audio/x-aiff',
'aiff' => 'audio/x-aiff',
'aifc' => 'audio/x-aiff',
'm3u' => 'audio/x-mpegurl',
'ram' => 'audio/x-pn-realaudio',
'rm' => 'audio/x-pn-realaudio',
'rpm' => 'audio/x-pn-realaudio-plugin',
'ra' => 'audio/x-realaudio',
'wav' => 'audio/x-wav',
'pdb' => 'chemical/x-pdb',
'xyz' => 'chemical/x-xyz',
'bmp' => 'image/bmp',
'gif' => 'image/gif',
'ief' => 'image/ief',
'jpeg' => 'image/jpeg',
'jpg' => 'image/jpeg',
'jpe' => 'image/jpeg',
'png' => 'image/png',
'tiff' => 'image/tiff',
'tif' => 'image/tiff',
'djvu' => 'image/vnd.djvu',
'djv' => 'image/vnd.djvu',
'wbmp' => 'image/vnd.wap.wbmp',
'ras' => 'image/x-cmu-raster',
'pnm' => 'image/x-portable-anymap',
'pbm' => 'image/x-portable-bitmap',
'pgm' => 'image/x-portable-graymap',
'ppm' => 'image/x-portable-pixmap',
'rgb' => 'image/x-rgb',
'xbm' => 'image/x-xbitmap',
'xpm' => 'image/x-xpixmap',
'xwd' => 'image/x-xwindowdump',
'igs' => 'model/iges',
'iges' => 'model/iges',
'msh' => 'model/mesh',
'mesh' => 'model/mesh',
'silo' => 'model/mesh',
'wrl' => 'model/vrml',
'vrml' => 'model/vrml',
'css' => 'text/css',
'html' => 'text/html',
'htm' => 'text/html',
'asc' => 'text/plain',
'txt' => 'text/plain',
'rtx' => 'text/richtext',
'rtf' => 'text/rtf',
'sgml' => 'text/sgml',
'sgm' => 'text/sgml',
'tsv' => 'text/tab-separated-values',
'wml' => 'text/vnd.wap.wml',
'wmls' => 'text/vnd.wap.wmlscript',
'etx' => 'text/x-setext',
'xsl' => 'text/xml',
'xml' => 'text/xml',
'mpeg' => 'video/mpeg',
'mpg' => 'video/mpeg',
'mpe' => 'video/mpeg',
'qt' => 'video/quicktime',
'mov' => 'video/quicktime',
'mxu' => 'video/vnd.mpegurl',
'avi' => 'video/x-msvideo',
'movie' => 'video/x-sgi-movie',
'ice' => 'x-conference/x-cooltalk'