diff --git a/web-service/src/main/java/cn/qaiu/lz/web/controller/PlaygroundApi.java b/web-service/src/main/java/cn/qaiu/lz/web/controller/PlaygroundApi.java
index 9a9a539..a5a1f0b 100644
--- a/web-service/src/main/java/cn/qaiu/lz/web/controller/PlaygroundApi.java
+++ b/web-service/src/main/java/cn/qaiu/lz/web/controller/PlaygroundApi.java
@@ -176,7 +176,7 @@ public class PlaygroundApi {
             startIndex += SESSION_KEY.length();
             int endIndex = cookie.indexOf(";", startIndex);
             
-            if (endIndex > startIndex) {
+            if (endIndex != -1) {
                 return cookie.substring(startIndex, endIndex).trim();
             } else {
                 return cookie.substring(startIndex).trim();