use XML::Simple;
use Data::Dumper;

my $tomcat_file = '/var/tomcat4/conf/server.xml';
my $tomcat_conf = XMLin($tomcat_file) or die "Error reading config: $!";
print Dumper $tomcat_conf;

#Modify hashref $tomcat_conf

my $modified_xml = XMLout($tomcat_conf, NoAttr => 1);
print Dumper $modified_conf;