一、示例
1.pom
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>2.7.2</version>
<relativePath/>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.session</groupId>
<artifactId>spring-session-data-redis</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-data-redis</artifactId>
</dependency>
</dependencies>2.HttpSessionListener
@Component
public class MyHttpSessionListener implements HttpSessionListener {
@Override
public void sessionCreated(HttpSessionEvent se) {
System.out.println("sessionCreated");
}
@Override
public void sessionDestroyed(HttpSessionEvent se) {
System.out.println("sessionDestroyed");
}
}3.controller
@RestController
public class IndexController {
private final static String SESSION_ATTRIBUTE = "UserId";
@GetMapping("/")
public String index() {
return "welcome to index!";
}
@GetMapping("/create")
public String create(HttpServletRequest request) {
HttpSession session = request.getSession();
session.setAttribute(SESSION_ATTRIBUTE, "1");
int interval = session.getMaxInactiveInterval();
System.out.println(interval);
return "create";
}
@GetMapping("/destroy")
public String destroy(HttpServletRequest request) {
HttpSession session = request.getSession();
session.invalidate();
return "destroy";
}
}4.application.yml
server:
port: 18080
servlet:
session:
timeout: 3600
spring:
redis:
host: 127.0.0.1
port: 6379二、注册 SessionRepositoryFilter 和 SessionEventHttpSessionListenerAdapter
// RedisSessionConfiguration.java
@Configuration(proxyBeanMethods = false)
@ConditionalOnClass({ RedisTemplate.class, RedisIndexedSessionRepository.class })
@ConditionalOnMissingBean(SessionRepository.class)
@ConditionalOnBean(RedisConnectionFactory.class)
@Conditional(ServletSessionCondition.class)
@EnableConfigurationProperties(RedisSessionProperties.class)
class RedisSessionConfiguration {
...
@Configuration(proxyBeanMethods = false)
public static class SpringBootRedisHttpSessionConfiguration extends RedisHttpSessionConfiguration {
@Autowired
public void customize(SessionProperties sessionProperties, RedisSessionProperties redisSessionProperties,
ServerProperties serverProperties) {
Duration timeout = sessionProperties
.determineTimeout(() -> serverProperties.getServlet().getSession().getTimeout());
if (timeout != null) {
setMaxInactiveIntervalInSeconds((int) timeout.getSeconds());
}
setRedisNamespace(redisSessionProperties.getNamespace());
setFlushMode(redisSessionProperties.getFlushMode());
setSaveMode(redisSessionProperties.getSaveMode());
setCleanupCron(redisSessionProperties.getCleanupCron());
}
}
}// RedisHttpSessionConfiguration.java
@Configuration(proxyBeanMethods = false)
public class RedisHttpSessionConfiguration extends SpringHttpSessionConfiguration
implements BeanClassLoaderAware, EmbeddedValueResolverAware, ImportAware {
private Integer maxInactiveIntervalInSeconds = MapSession.DEFAULT_MAX_INACTIVE_INTERVAL_SECONDS;
@Bean
public RedisIndexedSessionRepository sessionRepository() {
RedisTemplate<Object, Object> redisTemplate = createRedisTemplate();
RedisIndexedSessionRepository sessionRepository = new RedisIndexedSessionRepository(redisTemplate);
sessionRepository.setApplicationEventPublisher(this.applicationEventPublisher);
if (this.indexResolver != null) {
sessionRepository.setIndexResolver(this.indexResolver);
}
if (this.defaultRedisSerializer != null) {
sessionRepository.setDefaultSerializer(this.defaultRedisSerializer);
}
sessionRepository.setDefaultMaxInactiveInterval(this.maxInactiveIntervalInSeconds);
if (StringUtils.hasText(this.redisNamespace)) {
sessionRepository.setRedisKeyNamespace(this.redisNamespace);
}
sessionRepository.setFlushMode(this.flushMode);
sessionRepository.setSaveMode(this.saveMode);
int database = resolveDatabase();
sessionRepository.setDatabase(database);
this.sessionRepositoryCustomizers
.forEach((sessionRepositoryCustomizer) -> sessionRepositoryCustomizer.customize(sessionRepository));
return sessionRepository;
}
public void setMaxInactiveIntervalInSeconds(int maxInactiveIntervalInSeconds) {
this.maxInactiveIntervalInSeconds = maxInactiveIntervalInSeconds;
}
}// SpringHttpSessionConfiguration.java
@Configuration(proxyBeanMethods = false)
public class SpringHttpSessionConfiguration implements ApplicationContextAware {
@Bean
public <S extends Session> SessionRepositoryFilter<? extends Session> springSessionRepositoryFilter(
SessionRepository<S> sessionRepository) {
SessionRepositoryFilter<S> sessionRepositoryFilter = new SessionRepositoryFilter<>(sessionRepository);
sessionRepositoryFilter.setHttpSessionIdResolver(this.httpSessionIdResolver);
return sessionRepositoryFilter;
}
private List<HttpSessionListener> httpSessionListeners = new ArrayList<>();
@Autowired(required = false)
public void setHttpSessionListeners(List<HttpSessionListener> listeners) {
this.httpSessionListeners = listeners;
}
@Bean
public SessionEventHttpSessionListenerAdapter sessionEventHttpSessionListenerAdapter() {
return new SessionEventHttpSessionListenerAdapter(this.httpSessionListeners);
}
}三、包装 request, respose
1) 把 request 包装成 SessionRepositoryRequestWrapper
2) 把 response 包装成 SessionRepositoryResponseWrapper
// SessionRepositoryFilter.java
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
throws ServletException, IOException {
request.setAttribute(SESSION_REPOSITORY_ATTR, this.sessionRepository);
SessionRepositoryRequestWrapper wrappedRequest = new SessionRepositoryRequestWrapper(request, response);
SessionRepositoryResponseWrapper wrappedResponse = new SessionRepositoryResponseWrapper(wrappedRequest,
response);
try {
filterChain.doFilter(wrappedRequest, wrappedResponse);
}
finally {
wrappedRequest.commitSession();
}
}四、getSession()
1) getCurrentSession() 从 request 的 "org.springframework.session.SessionRepository.CURRENT_SESSION" 属性，获得 Session
2) getRequestedSession() 从 redis 中获得 session，requestedSession 类型是 RedisIndexedSessionRepository$RedisSession
getRequestedSession() 读取 redis 的 key 是 spring:session:sessions:e941ea64-3218-4304-9dec-ba346372d308 的值，取出 redis 值 lastAccessedTime 与 maxInactiveInterval 对比，判断 session 是否过期，如果过期，返回 null
3) requestedSession.setLastAccessedTime(Instant.now())，设置 RedisSession 的 Map<String, Object> delta 放入 lastAccessedTime 值
设置 RedisSession 的 MapSession 的 setLastAccessedTime
4) setCurrentSession(currentSession)，设置 request 的 "org.springframework.session.SessionRepository.CURRENT_SESSION" 值
// SessionRepositoryFilter$SessionRepositoryRequestWrapper.java
@Override
public HttpSessionWrapper getSession() {
return getSession(true);
}
@Override
public HttpSessionWrapper getSession(boolean create) {
HttpSessionWrapper currentSession = getCurrentSession();
if (currentSession != null) {
return currentSession;
}
S requestedSession = getRequestedSession();
if (requestedSession != null) {
if (getAttribute(INVALID_SESSION_ID_ATTR) == null) {
requestedSession.setLastAccessedTime(Instant.now());
this.requestedSessionIdValid = true;
currentSession = new HttpSessionWrapper(requestedSession, getServletContext());
currentSession.markNotNew();
setCurrentSession(currentSession);
return currentSession;
}
}
else {
...
setAttribute(INVALID_SESSION_ID_ATTR, "true");
}
if (!create) {
return null;
}
...
S session = SessionRepositoryFilter.this.sessionRepository.createSession();
session.setLastAccessedTime(Instant.now());
currentSession = new HttpSessionWrapper(session, getServletContext());
setCurrentSession(currentSession);
return currentSession;
}
private HttpSessionWrapper getCurrentSession() {
return (HttpSessionWrapper) getAttribute(CURRENT_SESSION_ATTR);
}
private S getRequestedSession() {
if (!this.requestedSessionCached) {
List<String> sessionIds = SessionRepositoryFilter.this.httpSessionIdResolver.resolveSessionIds(this);
for (String sessionId : sessionIds) {
if (this.requestedSessionId == null) {
this.requestedSessionId = sessionId;
}
S session = SessionRepositoryFilter.this.sessionRepository.findById(sessionId);
if (session != null) {
this.requestedSession = session;
this.requestedSessionId = sessionId;
break;
}
}
this.requestedSessionCached = true;
}
return this.requestedSession;
}五、session.setAttribute()
1) this.session.getAttribute(name)，this.session 是 RedisIndexedSessionRepository$RedisSession
从 this.session 的 MapSession cached 取得指定 name 的值
2) 把 value 放入 this.cached；把 value 放入 this.delta，key 为 "sessionAttr:UserId"，此时 this.delta 有两个 key，"lastAccessedTime" 和 "sessionAttr:UserId"
// SessionRepositoryFilter$SessionRepositoryRequestWrapper$HttpSessionWrapper.java
@Override
public void setAttribute(String name, Object value) {
checkState();
Object oldValue = this.session.getAttribute(name);
...
}// RedisIndexedSessionRepository$RedisSession.java
@Override
public <T> T getAttribute(String attributeName) {
T attributeValue = this.cached.getAttribute(attributeName);
...
return attributeValue;
}
@Override
public void setAttribute(String attributeName, Object attributeValue) {
this.cached.setAttribute(attributeName, attributeValue);
this.delta.put(getSessionAttrNameKey(attributeName), attributeValue);
flushImmediateIfNecessary();
}六、session.getAttribute
从 this.session 的 MapSession cached 取得指定 name 的值
// SessionRepositoryFilter$SessionRepositoryRequestWrapper$HttpSessionWrapper.java
@Override
public Object getAttribute(String name) {
checkState();
return this.session.getAttribute(name);
}七、commitSession()
当设置有效时间为 3600s
1) SessionRepositoryFilter.this.sessionRepository.save(session);
2) 当 delta 不为空时，会把 session 保存到 redis，并修改 redis 的 key 过期时间，即续期
3) key 为 spring:session:sessions:e941ea64-3218-4304-9dec-ba346372d308，是 hash 类型，放入 this.delta 的值，有 "lastAccessedTime" -> 1734156690429，"sessionAttr:UserId" -> "1"，"maxInactiveInterval" -> 3600，"creationTime" -> 1734156690429，设置 key 有效时间为 3600s + 5min
4) key 为 spring:session:expirations:1734164640000(1734164640000 是过期时间)，是 set 类型，值有 expires:e941ea64-3218-4304-9dec-ba346372d308，设置 key 有效时间为 3600s + 5min
可以把这种 key 看作是桶，每次保存 session 的 时候，如果上次访问与这次访问不在同一分钟内，会把值从旧桶移除，添加到新桶中
5) key 为 spring:session:sessions:expires:e941ea64-3218-4304-9dec-ba346372d308，是 string 类型，值为 ""，设置 key 有效时间为 3600s
6) this.sessionRedisOperations.convertAndSend 发布消息 channel 是 spring:session:event:0:created:e941ea64-3218-4304-9dec-ba346372d308，message 是 session.delta
7) this.requestedSessionCached = false
8) SessionRepositoryFilter.this.httpSessionIdResolver.setSessionId(this, this.response, sessionId)，执行写响应头 response.addHeader("Set-Cookie", "SESSION=e941ea64-3218-4304-9dec-ba346372d308; Path=/; HttpOnly; SameSite=Lax");
// SessionRepositoryFilter.java
@Override
protected void doFilterInternal(HttpServletRequest request, HttpServletResponse response, FilterChain filterChain)
throws ServletException, IOException {
request.setAttribute(SESSION_REPOSITORY_ATTR, this.sessionRepository);
SessionRepositoryRequestWrapper wrappedRequest = new SessionRepositoryRequestWrapper(request, response);
SessionRepositoryResponseWrapper wrappedResponse = new SessionRepositoryResponseWrapper(wrappedRequest,
response);
try {
filterChain.doFilter(wrappedRequest, wrappedResponse);
}
finally {
wrappedRequest.commitSession();
}
}// SessionRepositoryFilter$SessionRepositoryRequestWrapper
private void commitSession() {
HttpSessionWrapper wrappedSession = getCurrentSession();
if (wrappedSession == null) {
if (isInvalidateClientSession()) {
SessionRepositoryFilter.this.httpSessionIdResolver.expireSession(this, this.response);
}
}
else {
S session = wrappedSession.getSession();
clearRequestedSessionCache();
SessionRepositoryFilter.this.sessionRepository.save(session);
String sessionId = session.getId();
if (!isRequestedSessionIdValid() || !sessionId.equals(getRequestedSessionId())) {
SessionRepositoryFilter.this.httpSessionIdResolver.setSessionId(this, this.response, sessionId);
}
}
}
private void clearRequestedSessionCache() {
this.requestedSessionCached = false;
this.requestedSession = null;
this.requestedSessionId = null;
}// RedisIndexedSessionRepository.java
@Override
public void save(RedisSession session) {
session.save();
if (session.isNew) {
String sessionCreatedKey = getSessionCreatedChannel(session.getId());
this.sessionRedisOperations.convertAndSend(sessionCreatedKey, session.delta);
session.isNew = false;
}
}
final class RedisSession implements Session {
private void save() {
saveChangeSessionId();
saveDelta();
}
private void saveDelta() {
if (this.delta.isEmpty()) {
return;
}
String sessionId = getId();
getSessionBoundHashOperations(sessionId).putAll(this.delta);
String principalSessionKey = getSessionAttrNameKey(
FindByIndexNameSessionRepository.PRINCIPAL_NAME_INDEX_NAME);
String securityPrincipalSessionKey = getSessionAttrNameKey(SPRING_SECURITY_CONTEXT);
if (this.delta.containsKey(principalSessionKey) || this.delta.containsKey(securityPrincipalSessionKey)) {
if (this.originalPrincipalName != null) {
String originalPrincipalRedisKey = getPrincipalKey(this.originalPrincipalName);
RedisIndexedSessionRepository.this.sessionRedisOperations.boundSetOps(originalPrincipalRedisKey)
.remove(sessionId);
}
Map<String, String> indexes = RedisIndexedSessionRepository.this.indexResolver.resolveIndexesFor(this);
String principal = indexes.get(PRINCIPAL_NAME_INDEX_NAME);
this.originalPrincipalName = principal;
if (principal != null) {
String principalRedisKey = getPrincipalKey(principal);
RedisIndexedSessionRepository.this.sessionRedisOperations.boundSetOps(principalRedisKey)
.add(sessionId);
}
}
this.delta = new HashMap<>(this.delta.size());
Long originalExpiration = (this.originalLastAccessTime != null)
? this.originalLastAccessTime.plus(getMaxInactiveInterval()).toEpochMilli() : null;
RedisIndexedSessionRepository.this.expirationPolicy.onExpirationUpdated(originalExpiration, this);
}
}// RedisSessionExpirationPolicy.java
void onExpirationUpdated(Long originalExpirationTimeInMilli, Session session) {
String keyToExpire = SESSION_EXPIRES_PREFIX + session.getId();
long toExpire = roundUpToNextMinute(expiresInMillis(session));
if (originalExpirationTimeInMilli != null) {
long originalRoundedUp = roundUpToNextMinute(originalExpirationTimeInMilli);
if (toExpire != originalRoundedUp) {
String expireKey = getExpirationKey(originalRoundedUp);
this.redis.boundSetOps(expireKey).remove(keyToExpire);
}
}
long sessionExpireInSeconds = session.getMaxInactiveInterval().getSeconds();
String sessionKey = getSessionKey(keyToExpire);
if (sessionExpireInSeconds < 0) {
this.redis.boundValueOps(sessionKey).append("");
this.redis.boundValueOps(sessionKey).persist();
this.redis.boundHashOps(getSessionKey(session.getId())).persist();
return;
}
String expireKey = getExpirationKey(toExpire);
BoundSetOperations<Object, Object> expireOperations = this.redis.boundSetOps(expireKey);
expireOperations.add(keyToExpire);
long fiveMinutesAfterExpires = sessionExpireInSeconds + TimeUnit.MINUTES.toSeconds(5);
expireOperations.expire(fiveMinutesAfterExpires, TimeUnit.SECONDS);
if (sessionExpireInSeconds == 0) {
this.redis.delete(sessionKey);
}
else {
this.redis.boundValueOps(sessionKey).append("");
this.redis.boundValueOps(sessionKey).expire(sessionExpireInSeconds, TimeUnit.SECONDS);
}
this.redis.boundHashOps(getSessionKey(session.getId())).expire(fiveMinutesAfterExpires, TimeUnit.SECONDS);
}// CookieHttpSessionIdResolver.java
@Override
public void setSessionId(HttpServletRequest request, HttpServletResponse response, String sessionId) {
if (sessionId.equals(request.getAttribute(WRITTEN_SESSION_ID_ATTR))) {
return;
}
request.setAttribute(WRITTEN_SESSION_ID_ATTR, sessionId);
this.cookieSerializer.writeCookieValue(new CookieValue(request, response, sessionId));
}八、request.getSession().invalidate()
1) 移除 redis 中，key 为 spring:session:expirations:1734517620000 中 值 expires:ea063898-f4fe-4141-b38a-1496dcba28c9
2) 删除 key 为 spring:session:sessions:expires:ea063898-f4fe-4141-b38a-1496dcba28c9
3) 设置 maxInactiveInterval 为 0
4) 保存进 redis，如果 maxInactiveInterval 为 0，删除 key 是 spring:session:sessions:expires:ea063898-f4fe-4141-b38a-1496dcba28c9
3) requestedSessionCachedcommitSession，执行 SessionRepositoryFilter.this.httpSessionIdResolver.expireSession(this, this.response)，执行写响应头 response.addHeader("Set-Cookie", "SESSION=; Max-Age=0; Expires=Thu, 1 Jan 1970 00:00:00 GMT; Path=/; HttpOnly; SameSite=Lax")，同个浏览器请求，则不会携带 Cookie: SESSION=ea063898-f4fe-4141-b38a-1496dcba28c9 的请求头进行请求。当然可以通过其他方式携带这样的请求头，例如通过 curl 指定请求头，当 java 执行 getSession() 时，会从 redis 获得 key 为 spring:session:sessions:ea063898-f4fe-4141-b38a-1496dcba28c9 的值，此时得到的 maxInactiveInterval 为 0，是无效的 session
// SessionRepositoryFilter$SessionRepositoryRequestWrapper$HttpSessionWrapper
@Override
public void invalidate() {
super.invalidate();
SessionRepositoryRequestWrapper.this.requestedSessionInvalidated = true;
setCurrentSession(null);
clearRequestedSessionCache();
SessionRepositoryFilter.this.sessionRepository.deleteById(getId());
}
private void setCurrentSession(HttpSessionWrapper currentSession) {
if (currentSession == null) {
removeAttribute(CURRENT_SESSION_ATTR);
}
else {
setAttribute(CURRENT_SESSION_ATTR, currentSession);
}
}// RedisIndexedSessionRepository.java
@Override
public void deleteById(String sessionId) {
RedisSession session = getSession(sessionId, true);
if (session == null) {
return;
}
cleanupPrincipalIndex(session);
this.expirationPolicy.onDelete(session);
String expireKey = getExpiredKey(session.getId());
this.sessionRedisOperations.delete(expireKey);
session.setMaxInactiveInterval(Duration.ZERO);
save(session);
}// SessionRepositoryFilter$SessionRepositoryRequestWrapper
private void commitSession() {
HttpSessionWrapper wrappedSession = getCurrentSession();
if (wrappedSession == null) {
if (isInvalidateClientSession()) {
SessionRepositoryFilter.this.httpSessionIdResolver.expireSession(this, this.response);
}
}
else {
S session = wrappedSession.getSession();
clearRequestedSessionCache();
SessionRepositoryFilter.this.sessionRepository.save(session);
String sessionId = session.getId();
if (!isRequestedSessionIdValid() || !sessionId.equals(getRequestedSessionId())) {
SessionRepositoryFilter.this.httpSessionIdResolver.setSessionId(this, this.response, sessionId);
}
}
}// CookieHttpSessionIdResolver.java
@Override
public void expireSession(HttpServletRequest request, HttpServletResponse response) {
this.cookieSerializer.writeCookieValue(new CookieValue(request, response, ""));
}九、session 事件
RedisIndexedSessionRepository 订阅 redis
channel 为 __keyevent@0__:del、__keyevent@0__:expired
pattern 为 spring:session:event:0:created:*// RedisHttpSessionConfiguration.java
@Bean
public RedisMessageListenerContainer springSessionRedisMessageListenerContainer(
RedisIndexedSessionRepository sessionRepository) {
RedisMessageListenerContainer container = new RedisMessageListenerContainer();
container.setConnectionFactory(this.redisConnectionFactory);
if (this.redisTaskExecutor != null) {
container.setTaskExecutor(this.redisTaskExecutor);
}
if (this.redisSubscriptionExecutor != null) {
container.setSubscriptionExecutor(this.redisSubscriptionExecutor);
}
container.addMessageListener(sessionRepository,
Arrays.asList(new ChannelTopic(sessionRepository.getSessionDeletedChannel()),
new ChannelTopic(sessionRepository.getSessionExpiredChannel())));
container.addMessageListener(sessionRepository,
Collections.singletonList(new PatternTopic(sessionRepository.getSessionCreatedChannelPrefix() + "*")));
return container;
}利用 Redis 键空间通知机制，比如，在0号库，键 myKey 过期，会触发两个消息，等价于执行两个 publish 命令：publish __keyspace@0__:myKey expired 和 publish __keyevent@0__:expired myKey
publish <channel> <message>
keyspace事件订阅端 psubscribe __keyspace@0__:mykey
keyevent事件订阅端 psubscribe __keyevent@0__:expiredthis.sessionCreatedChannelPrefixBytes 是 spring:session:event:0:created: ，用于判断 channel 是否此可开头
this.expiredKeyPrefixBytes 是 spring:session:sessions:expires:，用于判断消息内容是否是此开头
this.sessionDeletedChannelBytes 是 __keyevent@0__:del，用于判断 channel 是否等于此
this.sessionExpiredChannelBytes 是 __keyevent@0__:expired，用于判断 channel 是否等于此1) 创建 session，保存 session 后
this.sessionRedisOperations.convertAndSend 发布消息 channel 是 spring:session:event:0:created:e941ea64-3218-4304-9dec-ba346372d308，message 是 <session.delta>
RedisIndexedSessionRepository 的 onMessage() 接受消息，触发 handleCreated() 方法，发布 SessionCreatedEvent
pattern 为 spring:session:event:0:created:*
channel 为 spring:session:event:0:created:e941ea64-3218-4304-9dec-ba346372d308
message 为 <session.delta>2) session 过期，接受消息，触发 handleExpired() 方法，发布 SessionExpiredEvent
pattern 为 __keyevent@0__:expired
channel 为 __keyevent@0__:expired
message 为 spring:session:sessions:expires:e941ea64-3218-4304-9dec-ba346372d3083) session 删除，接受消息，触发 handleExpired() 方法，发布 SessionExpiredEvent
pattern 为 __keyevent@0__:del
channel 为 __keyevent@0__:del
message 为 spring:session:sessions:expires:e941ea64-3218-4304-9dec-ba346372d308// RedisIndexedSessionRepository
@Override
public void onMessage(Message message, byte[] pattern) {
byte[] messageChannel = message.getChannel();
if (ByteUtils.startsWith(messageChannel, this.sessionCreatedChannelPrefixBytes)) {
...
Map<Object, Object> loaded = (Map<Object, Object>) this.defaultSerializer.deserialize(message.getBody());
handleCreated(loaded, new String(messageChannel));
return;
}
byte[] messageBody = message.getBody();
if (!ByteUtils.startsWith(messageBody, this.expiredKeyPrefixBytes)) {
return;
}
boolean isDeleted = Arrays.equals(messageChannel, this.sessionDeletedChannelBytes);
if (isDeleted || Arrays.equals(messageChannel, this.sessionExpiredChannelBytes)) {
String body = new String(messageBody);
int beginIndex = body.lastIndexOf(":") + 1;
int endIndex = body.length();
String sessionId = body.substring(beginIndex, endIndex);
RedisSession session = getSession(sessionId, true);
if (session == null) {
return;
}
...
if (isDeleted) {
handleDeleted(session);
}
else {
handleExpired(session);
}
}
}