update

src/components/student/studyStudent.vue

@@ -649,7 +649,7 @@
               <div>批</div>
               <div>
                 {{
-                  pz.username.length > 5
+                  pz.username && pz.username.length > 5
                   ? pz.username.substring(0, 5) + "..."
                   : pz.username
                 }}的批注

src/components/studyStudent.vue

@@ -5016,7 +5016,7 @@
               <div>批</div>
               <div>
                 {{
-                  pz.username.length > 5
+                  pz.username && pz.username.length > 5
                     ? pz.username.substring(0, 5) + "..."
                     : pz.username
                 }}的批注