原因：

从IIS或者Tomcat之类的Web服务器通过二进制流下载文件时（比如通过设置Header为Content-disposition:inline），如果被下载的文件是Office2007的dotx,docx,pot等后缀的时候，下载对话框中的图标会变成ZIP的，相应的文件名也会成为zip为扩展后缀的文件。其实出现这样的情况，是由于IE中对下载文件类型的判断，假如找不到相应后缀的MIME的话，会自动根据数据流来判断文件的类型，而微软对Office2007的格式做了和以前完全不同的处理。

以前的Office文档是100%的二进制格式。第三方的工具操作起来非常不方便，而 Office2007从整体上都是基于XML格式的，这里并不是说Office2007文档可以保存成XML格式。而是Office2007默认的文档格式就是XML的（Word的docx、Excel的xlsx等）。也许有人会感到奇怪，用文本编辑器打开docx后，显示的仍然是二进制格式，并不是什么 XML。其实docx并不是普通的XML格式，当然，也不只是一个XML文件，docx本质上是一个zip文件，里面有一系列的xml、目录和其他的文件。如果我们将docx改成zip。就可以用winzip等软件将其解开。

解决方案：

在Server端添加MIME映射就可以了。如Tomcat , 修改/%tomcat_home%/conf/web.xml

<mime-mapping>
	<extension>docx</extension>
	<mime-type>application/vnd.openxmlformats-officedocument.wordprocessingml.document</mime-type>
</mime-mapping>
<mime-mapping>
	<extension>xlsx</extension>
	<mime-type>application/vnd.openxmlformats-officedocument.spreadsheetml.sheet</mime-type>
</mime-mapping>
<mime-mapping>
	<extension>pptx</extension>
	<mime-type>application/vnd.openxmlformats-officedocument.presentationml.presentation</mime-type>
</mime-mapping>

附录：

下面收集了大部分文件的扩展名和相应的MIME对应，有需要的可以在列表中找到并添加。

.asx,video/x-ms-asf
.xml,text/xml
.tsv,text/tab-separated-values
.ra,audio/x-pn-realaudio
.sv4crc,application/x-sv4crc
.spc,application/x-pkcs7-certificates
.pmc,application/x-perfmon
.lit,application/x-ms-reader
.crd,application/x-mscardfile
.isp,application/x-internet-signup
.wmlsc,application/vnd.wap.wmlscriptc
.vst,application/vnd.visio
.xlam,application/vnd.ms-excel.addin.macroEnabled.12
.ttf,application/octet-stream
.pfm,application/octet-stream
.csv,application/octet-stream
.aaf,application/octet-stream
.one,application/onenote
.hta,application/hta
.atom,application/atom+xml
.323,text/h323
.mhtml,message/rfc822
.midi,audio/mid
.p7r,application/x-pkcs7-certreqresp
.mny,application/x-msmoney
.clp,application/x-msclip
.vsd,application/vnd.visio
.lpk,application/octet-stream
.bin,application/octet-stream
.onetoc,application/onenote
.x,application/directx
.wvx,video/x-ms-wvx
.vcf,text/x-vcard
.htc,text/x-component
.htt,text/webviewhtml
.h,text/plain
.mht,message/rfc822
.mid,audio/mid
.p7b,application/x-pkcs7-certificates
.gz,application/x-gzip
.dvi,application/x-dvi
.cpio,application/x-cpio
.vdx,application/vnd.ms-visio.viewer
.sldm,application/vnd.ms-powerpoint.slide.macroEnabled.12
.xlm,application/vnd.ms-excel
.fdf,application/vnd.fdf
.setreg,application/set-registration-initiation
.eps,application/postscript
.p7s,application/pkcs7-signature
.toc,application/octet-stream
.mdp,application/octet-stream
.ics,application/octet-stream
.chm,application/octet-stream
.asi,application/octet-stream
.afm,application/octet-stream
.evy,application/envoy
.wmp,video/x-ms-wmp
.qt,video/quicktime
.mpv2,video/mpeg
.xslt,text/xml
.etx,text/x-setext
.cod,image/cis-cod
.snd,audio/basic
.au,audio/basic
.man,application/x-troff-man
.qtl,application/x-quicktimeplayer
.pmw,application/x-perfmon
.class,application/x-java-applet
.iii,application/x-iphone
.csh,application/x-csh
.z,application/x-compress
.vtx,application/vnd.visio
.vsw,application/vnd.visio
.wps,application/vnd.ms-works
.potx,application/vnd.openxmlformats-officedocument.presentationml.template
.ps,application/postscript
.p7c,application/pkcs7-mime
.thn,application/octet-stream
.mso,application/octet-stream
.dot,application/msword
.doc,application/msword
.sgml,text/sgml
.nws,message/rfc822
.pbm,image/x-portable-bitmap
.ief,image/ief
.wav,audio/wav
.texi,application/x-texinfo
.mvb,application/x-msmediaview
.hdf,application/x-hdf
.vsx,application/vnd.visio
.dotm,application/vnd.ms-word.template.macroEnabled.12
.docm,application/vnd.ms-word.document.macroEnabled.12
.pptx,application/vnd.openxmlformats-officedocument.presentationml.presentation
.psm,application/octet-stream
.java,application/octet-stream
.eot,application/octet-stream
.jar,application/java-archive
.mpeg,video/mpeg
.xsf,text/xml
.map,text/plain
.uls,text/iuls
.rf,image/vnd.rn-realflash
.m3u,audio/x-mpegurl
.wma,audio/x-ms-wma
.aifc,audio/aiff
.mdb,application/x-msaccess
.mvc,application/x-miva-compiled
.stl,application/vnd.ms-pki.stl
.ppsx,application/vnd.openxmlformats-officedocument.presentationml.slideshow
.xlsb,application/vnd.ms-excel.sheet.binary.macroEnabled.12
.setpay,application/set-payment-initiation
.prm,application/octet-stream
.mix,application/octet-stream
.lzh,application/octet-stream
.hhk,application/octet-stream
.onepkg,application/onenote
.xaf,x-world/x-vrml
.flr,x-world/x-vrml
.IVF,video/x-ivf
.cnf,text/plain
.asm,text/plain
.tiff,image/tiff
.wax,audio/x-ms-wax
.ms,application/x-troff-ms
.tcl,application/x-tcl
.shar,application/x-shar
.sh,application/x-sh
.nc,application/x-netcdf
.hlp,application/winhlp
.oda,application/oda
.pfb,application/octet-stream
.fla,application/octet-stream
.wm,video/x-ms-wm
.rgb,image/x-rgb
.ppm,image/x-portable-pixmap
.ram,audio/x-pn-realaudio
.sit,application/x-stuffit
.dir,application/x-director
.mpp,application/vnd.ms-project
.xla,application/vnd.ms-excel
.ssm,application/streamingmedia
.axs,application/olescript
.ods,application/oleobject
.psp,application/octet-stream
.jpb,application/octet-stream
.wrz,x-world/x-vrml
.m1v,video/mpeg
.mno,text/xml
.cmx,image/x-cmx
.jpeg,image/jpeg
.dib,image/bmp
.rmi,audio/mid
.aiff,audio/aiff
.wmd,application/x-ms-wmd
.wri,application/x-mswrite
.pub,application/x-mspublisher
.ins,application/x-internet-signup
.wks,application/vnd.ms-works
.xls,application/vnd.ms-excel
.ai,application/postscript
.crl,application/pkix-crl
.qxd,application/octet-stream
.dwp,application/octet-stream
.xof,x-world/x-vrml
.wmv,video/x-ms-wmv
.nsc,video/x-ms-asf
.mpa,video/mpeg
.pnm,image/x-portable-anymap
.rpm,audio/x-pn-realaudio-plugin
.aif,audio/x-aiff
.me,application/x-troff-me
.pml,application/x-perfmon
.trm,application/x-msterminal
.m13,application/x-msmediaview
.js,application/x-javascript
.dxr,application/x-director
.potm,application/vnd.ms-powerpoint.template.macroEnabled.12
.xltx,application/vnd.openxmlformats-officedocument.spreadsheetml.template
.xlt,application/vnd.ms-excel
.xlc,application/vnd.ms-excel
.p10,application/pkcs10
.smi,application/octet-stream
.sea,application/octet-stream
.hqx,application/mac-binhex40
.spl,application/futuresplash
.movie,video/x-sgi-movie
.lsf,video/x-la-asf
.txt,text/plain
.jfif,image/pjpeg
.jpe,image/jpeg
.zip,application/x-zip-compressed
.wmf,application/x-msmetafile
.m14,application/x-msmediaview
.latex,application/x-latex
.wcm,application/vnd.ms-works
.pptm,application/vnd.ms-powerpoint.presentation.macroEnabled.12
.xlsx,application/vnd.openxmlformats-officedocument.spreadsheetml.sheet
.hhp,application/octet-stream
.aca,application/octet-stream
.accdb,application/msaccess
.jcz,application/liquidmotion
.wrl,x-world/x-vrml
.wmx,video/x-ms-wmx
.asr,video/x-ms-asf
.lsx,video/x-la-asf
.xsl,text/xml
.html,text/html
.tif,image/tiff
.der,application/x-x509-ca-cert
.pfx,application/x-pkcs12
.p12,application/x-pkcs12
.ppsm,application/vnd.ms-powerpoint.slideshow.macroEnabled.12
.cur,application/octet-stream
.accdt,application/msaccess
.hdml,text/x-hdml
.htm,text/html
.xbm,image/x-xbitmap
.jpg,image/jpeg
.texinfo,application/x-texinfo
.ppam,application/vnd.ms-powerpoint.addin.macroEnabled.12
.xlw,application/vnd.ms-excel
.rm,application/vnd.rn-realmedia
.pdf,application/pdf
.rar,application/octet-stream
.psd,application/octet-stream
.inf,application/octet-stream
.emz,application/octet-stream
.dsp,application/octet-stream
.onea,application/onenote
.jck,application/liquidmotion
.mpe,video/mpeg
.mp2,video/mpeg
.sct,text/scriptlet
.ras,image/x-cmu-raster
.swf,application/x-shockwave-flash
.wmz,application/x-ms-wmz
.gtar,application/x-gtar
.dcr,application/x-director
.sldx,application/vnd.openxmlformats-officedocument.presentationml.slide
.pps,application/vnd.ms-pps
.p7m,application/pkcs7-mime
.xsn,application/octet-stream
.ocx,application/octet-stream
.accde,application/msaccess
.mov,video/quicktime
.wmls,text/vnd.wap.wmlscript
.cpp,text/plain
.c,text/plain
.bas,text/plain
.css,text/css
.art,image/x-jg
.mp3,audio/mpeg
.t,application/x-troff
.roff,application/x-troff
.tar,application/x-tar
.hhc,application/x-oleobject
.scd,application/x-msschedule
.pko,application/vnd.ms-pki.pko
.sst,application/vnd.ms-pki.certstore
.ppt,application/vnd.ms-powerpoint
.xtp,application/octet-stream
.u32,application/octet-stream
.pcx,application/octet-stream
.msi,application/octet-stream
.exe,application/octet-stream
.asd,application/octet-stream
.onetoc2,application/onenote
.fif,application/fractals
.mpg,video/mpeg
.vml,text/xml
.xdr,text/plain
.vcs,text/plain
.hxt,text/html
.eml,message/rfc822
.xpm,image/x-xpixmap
.ico,image/x-icon
.gif,image/gif
.dwf,drawing/x-dwf
.src,application/x-wais-source
.tr,application/x-troff
.pmr,application/x-perfmon
.pma,application/x-perfmon
.dll,application/x-msdownload
.bcpio,application/x-bcpio
.wmlc,application/vnd.wap.wmlc
.wdb,application/vnd.ms-works
.dotx,application/vnd.openxmlformats-officedocument.wordprocessingml.template
.docx,application/vnd.openxmlformats-officedocument.wordprocessingml.document
.pot,application/vnd.ms-powerpoint
.xltm,application/vnd.ms-excel.template.macroEnabled.12
.rtf,application/rtf
.prf,application/pics-rules
.snp,application/octet-stream
.cab,application/octet-stream
.avi,video/x-msvideo
.asf,video/x-ms-asf
.dtd,text/xml
.wml,text/vnd.wap.wml
.vbs,text/vbscript
.rtx,text/richtext
.dlm,text/dlm
.xwd,image/x-xwindowdump
.pgm,image/x-portable-graymap
.bmp,image/bmp
.crt,application/x-x509-ca-cert
.ustar,application/x-ustar
.tex,application/x-tex
.sv4cpio,application/x-sv4cpio
.tgz,application/x-compressed
.cdf,application/x-cdf
.vss,application/vnd.visio
.cat,application/vnd.ms-pki.seccat
.thmx,application/vnd.ms-officetheme
.xlsm,application/vnd.ms-excel.sheet.macroEnabled.12
.prx,application/octet-stream
.pcz,application/octet-stream
.onetmp,application/onenote
.acx,application/internet-property-stream
.wsdl,text/xml
.disco,text/xml
.xsd,text/xml
.wbmp,image/vnd.wap.wbmp
.png,image/png
.pnz,image/png
.smd,audio/x-smd
.smz,audio/x-smd
.smx,audio/x-smd
.mmf,application/x-smaf