一种可能的方法是覆盖默认的WebSessionManager配置，并使用手动创建的InMemoryWebSessionStore bean设置会话存储。

@Configuration
public class SessionConfig {

    @Bean
    public WebSessionManager webSessionManager (WebSessionStore webSessionStore) {
        DefaultWebSessionManager webSessionManager = new DefaultWebSessionManager();
        webSessionManager.setSessionStore(webSessionStore);
        return webSessionManager;
    }

    @Bean
    public InMemoryWebSessionStore inMemoryWebSessionStore() {
        return new InMemoryWebSessionStore();
    }

}

然后在注销逻辑中，我们可以注入InMemoryWebSessionStore bean，检索所有会话并执行注销：

@Service
public class SessionService {

    private InMemoryWebSessionStore webSessionStore;

    public SessionService(InMemoryWebSessionStore webSessionStore) {
        this.webSessionStore = webSessionStore;
    }

    private Mono<Void> performLogout(String issuer, String subject) {
       String sessionId = webSessionStore.getSessions()
                .entrySet().stream()
                .filter(e -> shouldBeRemoved(issuer, subject, e.getValue()))
                .findFirst() // assuming issuer and subject combination is always unique
                .map(Map.Entry::getKey)
                .orElse("dummy-session-id");
       return webSessionStore.removeSession(sessionId);
    }

    private boolean shouldBeRemoved(String issuer, String subject, WebSession session) {
        OidcUser oidcUser = oidcUserFromSession(session);
        return issuer.equals(oidcUser.getIssuer().toString()) && subject.equals(oidcUser.getSubject());
    }

    private OidcUser oidcUserFromSession(WebSession session) {
        SecurityContext securityContext = session.getAttribute(WebSessionServerSecurityContextRepository
                .DEFAULT_SPRING_SECURITY_CONTEXT_ATTR_NAME);
        return (OidcUser) securityContext.getAuthentication().getPrincipal();
    }

}

来自@elyorbek-ibrokhimov的答案并没有满足我的需求，即挂钩到会话生命周期，但它确实让我走上了正确的轨道。非常感谢他。以下是我如何实现它（灵感来自MaxIdleTimeInMemoryWebSessionStore）：

@Bean
WebSessionManager webSessionManager(WebSessionStore webSessionStore) {
    DefaultWebSessionManager webSessionManager = new DefaultWebSessionManager();
    webSessionManager.setSessionStore(webSessionStore);
    return webSessionManager;
}

@Bean
WebSessionStore webSessionStore(ServerProperties serverProperties) {
    return new SpringAddonsWebSessionStore(serverProperties.getReactive().getSession().getTimeout());
}

public static interface WebSessionListener {

    default void sessionCreated(WebSession session) {
    }

    default void sessionRemoved(String sessionId) {
    }
}

static class SpringAddonsWebSessionStore implements WebSessionStore {
    private final InMemoryWebSessionStore delegate = new InMemoryWebSessionStore();
    private final ConcurrentLinkedQueue<WebSessionListener> webSessionListeners = new ConcurrentLinkedQueue<WebSessionListener>();

    private final Duration timeout;

    public SpringAddonsWebSessionStore(Duration timeout) {
        this.timeout = timeout;
    }
    
    public void addWebSessionListener(WebSessionListener listener) {
        webSessionListeners.add(listener);
    }

    @Override
    public Mono<WebSession> createWebSession() {
        return delegate.createWebSession().doOnSuccess(this::setMaxIdleTime)
                .doOnSuccess(session -> webSessionListeners.forEach(l -> l.sessionCreated(session)));
    }

    @Override
    public Mono<WebSession> retrieveSession(String sessionId) {
        return delegate.retrieveSession(sessionId);
    }

    @Override
    public Mono<Void> removeSession(String sessionId) {
        webSessionListeners.forEach(l -> l.sessionRemoved(sessionId));
        return delegate.removeSession(sessionId);
    }

    @Override
    public Mono<WebSession> updateLastAccessTime(WebSession webSession) {
        return delegate.updateLastAccessTime(webSession);
    }

    private void setMaxIdleTime(WebSession session) {
        session.setMaxIdleTime(this.timeout);
    }
}

现在，我可以针对这个WebSessionStore注册一个定制的授权客户端存储库，并让它收到sessionCreated和sessionRemoved事件的通知，以更新它自己的索引。