public void setLoginUrl(String loginUrl) {
        this.loginUrl = loginUrl;
    }
Sets the login URL used to authenticate a user.
<p/>
Most Shiro filters use this url as the location to redirect a user when the filter requires
authentication.  Unless overridden, the {@link #DEFAULT_LOGIN_URL DEFAULT_LOGIN_URL} is assumed.

@param loginUrl the login URL used to authenticate a user, used when redirecting users if authentication is required.
web/src/main/java/org/apache/shiro/web/filter/AccessControlFilter.java