map_defaults.xml

<?xml version="1.0" encoding="UTF-8" ?>
<routes xmlns="http://symfony.com/schema/routing"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://symfony.com/schema/routing
        https://symfony.com/schema/routing/routing-1.0.xsd">

    <route id="blog" path="/blog">
        <default key="_controller">
            <string>AcmeBlogBundle:Blog:index</string>
        </default>
        <default key="values">
            <map>
                <bool key="public">true</bool>
                <int key="page">1</int>
                <float key="price">3.5</float>
                <string key="title">foo</string>
            </map>
        </default>
    </route>
</routes>