我们用浏览器打开文件的时候会发现如果是doc文件， 会用记事本打开，出现乱码， 但是如果在web.xml里面配置了类型，浏览器就会根据配置的类型自动调用相应的程序打开
在 WEB.XML 配置常用文件类型
<mime-mapping>
<extension>doc</extension>
<mime-type>application/vnd.ms-word</mime-type>
</mime-mapping>
<mime-mapping>
<extension>gif</extension>
<mime-type>image/gif</mime-type>
</mime-mapping>
<mime-mapping>
<extension>htm</extension>
<mime-type>text/html</mime-type>
</mime-mapping>
<mime-mapping>
<extension>html</extension>
<mime-type>text/html</mime-type>
</mime-mapping>
<mime-mapping>
<extension>jnlp</extension>
<mime-type>application/x-java-jnlp-file</mime-type>
</mime-mapping>
<mime-mapping>
<extension>jpeg</extension>
<mime-type>image/jpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>jpg</extension>
<mime-type>image/jpeg</mime-type>
</mime-mapping>
<mime-mapping>
<extension>js</extension>
<mime-type>application/x-javascript</mime-type>
</mime-mapping>
<mime-mapping>
<extension>pdf</extension>
<mime-type>application/pdf</mime-type>
</mime-mapping>
<mime-mapping>
<extension>png</extension>
<mime-type>image/png</mime-type>
</mime-mapping>
<mime-mapping>
<extension>rar</extension>
<mime-type>application/x-rar-compressed</mime-type>
</mime-mapping>
<mime-mapping>
<extension>txt</extension>
<mime-type>text/plain</mime-type>
</mime-mapping>
<mime-mapping>
<extension>xls</extension>
<mime-type>application/vnd.ms-excel</mime-type>
</mime-mapping>
<mime-mapping>
<extension>xml</extension>
<mime-type>text/xml</mime-type>
</mime-mapping>
<mime-mapping>
<extension>xul</extension>
<mime-type>application/vnd.mozilla.xul-xml</mime-type>
</mime-mapping>
<mime-mapping>
<extension>zhtml</extension>
<mime-type>text/html</mime-type>
</mime-mapping>
<mime-mapping>
<extension>zip</extension>
<mime-type>application/x-zip</mime-type>
</mime-mapping>
<mime-mapping>
<extension>zul</extension>
<mime-type>text/html</mime-type>
</mime-mapping>
