Personnaliser la page d'authentification

protected void configure(HttpSecurity http) throws Exception {
    http
        .authorizeRequests()
            .anyRequest().authenticated()
            .and()
        .formLogin()
            .loginPage("/login")
            .permitAll(); // ne pas soumettre à l'authentification, la page de connexion
}

Exemple de page d'authentification

<c:url value="/login" var="loginUrl"/>
<form action="${loginUrl}" method="post">
    <c:if test="${param.error != null}">
        <p>Invalid username and password.</p>
    </c:if>
    <c:if test="${param.logout != null}">
        <p>You have been logged out.</p>
    </c:if>
    <p>
        <label for="username">Username</label>
        <input type="text" id="username" name="username"/>
    </p>
    <p>
        <label for="password">Password</label>
        <input type="password" id="password" name="password"/>
    </p>
    <input type="hidden" name="${_csrf.parameterName}" value="${_csrf.token}"/>
    <button type="submit" class="btn">Log in</button>
</form>