diff --git a/examples/req_auth.rs b/examples/req_auth.rs
index cc7ca6c..455ccf9 100644
--- a/examples/req_auth.rs
+++ b/examples/req_auth.rs
@@ -167,7 +167,7 @@ async fn choose_course(all_course: &Vec<Value>, client: Client) -> Result<(), Bo
             "\n\nCourse id: {}, Course name: {}, Course teacher: {} {}",
             course["id"].as_str().unwrap().green().bold(),
             course["kcmc"].as_str().unwrap().purple().bold(),
-            course["dgjsmc"].as_str().unwrap().blue().bold(),
+            course["dgjsmc"].as_str().unwrap_or("").blue().bold(),
             course["tyxmmc"].as_str().unwrap_or("").blue().bold(),
         );
 
diff --git a/src/main.rs b/src/main.rs
index 7579ef0..46d5a84 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -93,7 +93,7 @@ async fn choose_course(all_course: &Vec<Value>, cookie: &str) -> Result<(), Box<
             "\n\nCourse id: {}, Course name: {}, Course teacher: {} {}",
             course["id"].as_str().unwrap().green().bold(),
             course["kcmc"].as_str().unwrap().purple().bold(),
-            course["dgjsmc"].as_str().unwrap().blue().bold(),
+            course["dgjsmc"].as_str().unwrap_or("").blue().bold(),
             course["tyxmmc"].as_str().unwrap_or("").blue().bold(),
         );