update..

examcloud-support/src/main/java/cn/com/qmth/examcloud/commons/util/StringUtil.java

@@ -89,6 +89,13 @@ public class StringUtil {
 
     }
 
+    public static String substring(String str, int maxLength) {
+        if (StringUtils.length(str) > maxLength) {
+            return str.substring(0, maxLength);
+        }
+        return str;
+    }
+
     /**
      * @param in
      * @return