struts.xml——这里是重点

<!DOCTYPE struts PUBLIC"-//Apache Software Foundation//DTD Struts Configuration 2.0//EN""http://struts.apache.org/dtds/struts-2.0.dtd"><struts><package name="default" extends="struts-default">   <action name="download" class="action.DownloadAction">      <result type="stream"><param name="contentType">application/octet-stream</param><param name="inputName">inputStream</param><param name="contentDisposition">attachment;filename="${fileName}"</param><param name="bufferSize">4096</param>      </result>   </action></package></struts>当result为stream类型时，struts2会自动根据你配置好的参数下载文件。其中主要使用的参数是：contentType 指定下载文件的文件类型 —— application/octet-stream 表示无限制inputName 流对象名 —— 比如这里写inputStream，它就会自动去找Action中的getInputStream方法。contentDisposition 使用经过转码的文件名作为下载文件名 —— 默认格式是attachment;filename="${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：package action;import java.io.InputStream;import org.apache.struts2.ServletActionContext;public class DownloadAction { private String fileName;public void setFileName(String fileName) { this.fileName = fileName;}public InputStream getInputStream() { return ServletActionContext.getServletContext().getResourceAsStream("/" + fileName);}public String execute(){ return "success";}}* 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-javascript', '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'