Oh I think I've found the answer I just have to set command line or xml file in my tomcat like this
<?xml version="1.0" encoding="UTF-8" ?>
<Context docBase="pathto\appname.war" path="javamelody" reloadable="false" >
<Parameter name='javamelody.storage-directory' value='pathname' override='false'/>
</Context>
Thank you for the help :D