在web.xml最后加上如下声明：
<mime-mapping>
<extension>doc</extension>
<mime-type>application/msword</mime-type>
</mime-mapping>
<mime-mapping>
<extension>xls</extension>
<mime-type>application/x-msexcel</mime-type>
</mime-mapping>
<mime-mapping>
<extension>zip</extension>
<mime-type>application/octet-stream</mime-type>
</mime-mapping>
<mime-mapping>
<extension>rar</extension>
<mime-type>application/octet-stream</mime-type>
</mime-mapping>