diff --git a/webmagic-samples/src/main/java/us/codecraft/webmagic/model/samples/GithubRepo.java b/webmagic-samples/src/main/java/us/codecraft/webmagic/model/samples/GithubRepo.java
index 941bdbde..136e88d9 100644
--- a/webmagic-samples/src/main/java/us/codecraft/webmagic/model/samples/GithubRepo.java
+++ b/webmagic-samples/src/main/java/us/codecraft/webmagic/model/samples/GithubRepo.java
@@ -49,7 +49,7 @@ public class GithubRepo implements HasKey {
 
     @Override
     public String key() {
-        return author+":"+name;
+        return author+"_"+name;
     }
 
     public String getName() {