Q: Tomcat did not decode the uri (particularly the file download link) correctly, why? 

A: Tomcat 5 and later use ISO-8859-1 for the URI encoding/decoding by default. If you are using UTF-8,
   you must add URIEncoding="UTF-8" useBodyEncodingForURI="true" into the Connector, such
   like the following (in Tomcat's conf/server.xml):

    <Connector port="8080" URIEncoding="UTF-8" useBodyEncodingForURI="true"
               maxThreads="150" minSpareThreads="25" maxSpareThreads="75"
               enableLookups="false" redirectPort="8443" acceptCount="100"
               debug="0" connectionTimeout="20000" 
               disableUploadTimeout="true" />


   NOTE: this is no longer an issue since Bugzero version 6.1 where the filename in the uri is
         encoded in Base64.