public void setUrl(String url) {
        this.url = url;
    }
Used when initializing the default {@link LdapContextFactory}.  This property is ignored if a custom
<tt>LdapContextFactory</tt> is specified.

@param url the LDAP url.
@see JndiLdapContextFactory#setUrl(String)
core/src/main/java/org/apache/shiro/realm/ldap/AbstractLdapRealm.java