diff --git a/cloud-rule-engine/src/main/java/com/muyu/compile/FilesCompilerLoad.java b/cloud-rule-engine/src/main/java/com/muyu/compile/FilesCompilerLoad.java
index dc256d7..497be53 100644
--- a/cloud-rule-engine/src/main/java/com/muyu/compile/FilesCompilerLoad.java
+++ b/cloud-rule-engine/src/main/java/com/muyu/compile/FilesCompilerLoad.java
@@ -66,7 +66,7 @@ public class FilesCompilerLoad {
             log.info(externalClassFilePath);
             Path path = Paths.get(externalClassFilePath);
 
-            String externalClassDir = externalClassFilePath.substring(0, externalClassFilePath.lastIndexOf("/"));
+            String externalClassDir = externalClassFilePath.substring(0, externalClassFilePath.lastIndexOf('/'));
 
             URL[] urls = new URL[]{new File(externalClassDir).toURI().toURL()};