tomcat 支持文件下载

<mime-mapping> 
<extension>doc</extension>
<mime-type>application/msword</mime-type> 
</mime-mapping> 
<mime-mapping> 
<extension>xls</extension> 
<mime-type>application/msexcel</mime-type> 
</mime-mapping> 
<mime-mapping> 
<extension>pdf</extension> 
<mime-type>application/pdf</mime-type> 
</mime-mapping>
<mime-mapping> 
<extension>zip</extension> 
<mime-type>application/zip</mime-type> 
</mime-mapping>
<mime-mapping> 
<extension>rar</extension> 
<mime-type>application/rar</mime-type> 
</mime-mapping>
<mime-mapping> 
<extension>txt</extension> 
<mime-type>application/rar</mime-type> 
</mime-mapping>
<mime-mapping> 
<extension>chm</extension> 
<mime-type>application/rar</mime-type>
</mime-mapping>

<mime-mapping> 
<extension>RAR</extension> 
<mime-type>application/rar</mime-type> 
</mime-mapping>

<mime-mapping> 
<extension>ZIP</extension> 
<mime-type>application/zip</mime-type> 
</mime-mapping>

<mime-mapping> 
<extension>CHM</extension> 
<mime-type>application/rar</mime-type>
</mime-mapping>

<mime-mapping> 
<extension>iso</extension> 
<mime-type>application/rar</mime-type>
</mime-mapping>

<mime-mapping> 
<extension>ISO</extension> 
<mime-type>application/rar</mime-type>
</mime-mapping>

<mime-mapping> 
<extension>exe</extension> 
<mime-type>application/rar</mime-type>
</mime-mapping>

<mime-mapping> 
<extension>EXE</extension> 
<mime-type>application/rar</mime-type>
</mime-mapping>