diff --git a/bundles/org.openhab.binding.digitalstrom/src/main/java/org/openhab/binding/digitalstrom/internal/lib/serverconnection/impl/HttpTransportImpl.java b/bundles/org.openhab.binding.digitalstrom/src/main/java/org/openhab/binding/digitalstrom/internal/lib/serverconnection/impl/HttpTransportImpl.java
index 1c63bb82b8130..ff8adab9bef9d 100644
--- a/bundles/org.openhab.binding.digitalstrom/src/main/java/org/openhab/binding/digitalstrom/internal/lib/serverconnection/impl/HttpTransportImpl.java
+++ b/bundles/org.openhab.binding.digitalstrom/src/main/java/org/openhab/binding/digitalstrom/internal/lib/serverconnection/impl/HttpTransportImpl.java
@@ -43,6 +43,7 @@
 import javax.net.ssl.TrustManager;
 import javax.net.ssl.X509TrustManager;
 
+import org.apache.commons.lang3.StringUtils;
 import org.openhab.binding.digitalstrom.internal.lib.config.Config;
 import org.openhab.binding.digitalstrom.internal.lib.manager.ConnectionManager;
 import org.openhab.binding.digitalstrom.internal.lib.serverconnection.HttpTransport;
@@ -333,8 +334,7 @@ private String checkSessionToken(String request) {
     }
 
     private boolean checkNeededSessionToken(String request) {
-        String requestFirstPart = request.substring(0, request.indexOf("?"));
-        String functionName = requestFirstPart.substring(requestFirstPart.lastIndexOf("/") + 1);
+        String functionName = StringUtils.substringAfterLast(StringUtils.substringBefore(request, "?"), "/");
         return !DsAPIImpl.METHODS_MUST_NOT_BE_LOGGED_IN.contains(functionName);
     }
 
@@ -347,10 +347,8 @@ private String addSessionToken(String request, String sessionToken) {
                 correctedRequest = correctedRequest + "?" + ParameterKeys.TOKEN + "=" + sessionToken;
             }
         } else {
-            String strippedRequest = correctedRequest
-                    .substring(correctedRequest.indexOf(ParameterKeys.TOKEN + "=") + ParameterKeys.TOKEN.length() + 1);
-            strippedRequest = strippedRequest.substring(0, strippedRequest.lastIndexOf("&"));
-            correctedRequest = correctedRequest.replaceFirst(strippedRequest, sessionToken);
+            correctedRequest = StringUtils.replaceOnce(correctedRequest, StringUtils.substringBefore(
+                    StringUtils.substringAfter(correctedRequest, ParameterKeys.TOKEN + "="), "&"), sessionToken);
         }
         return correctedRequest;
     }