fix a bug

src/main/java/cn/quantgroup/xyqb/service/session/impl/SessionServiceImpl.java

@@ -43,13 +43,11 @@ public class SessionServiceImpl implements ISessionService{
         //获取sessionid
         String sessionId = findSessionIdByUserIdLoginProperties(user.getId(), properties);
         if (StringUtils.length(sessionId) == 36) {
-            sessionStruct = new SessionStruct();
-            String sessionValue = findSessionValueBySessionId(sessionId);
-            if (StringUtils.isEmpty(sessionValue)) {
+            sessionStruct = findSessionBySessionId(sessionId);
+            if (sessionStruct == null) {
                 sessionStruct = newSession(user, properties);
                 persistSession(sessionStruct.getSid(), sessionStruct.getValues());
             }
-            sessionStruct.setSid(sessionId);
         } else {
             sessionStruct = newSession(user, properties);
             persistSession(sessionStruct.getSid(), sessionStruct.getValues());