I would to run buildr on my svn repository - to build the files from \src\main\java in the subversion repository with username and password and save it to anther location on my disc.
How can I do it?
if i understand your question correctly, you are trying to setup a contiuous build system. checking out source code is the responsibility of your CI system. it would poll your svn, git or whatever cvs you use for changes and then build it on the configuration you provide.
a free build-server is jenkins (aka hudson). if you want a hosted solution you can go for travis-ci (it's free). or something expensive like atlassian bamboo.