...

examcloud-task-api-provider/src/main/java/cn/com/qmth/examcloud/task/api/controller/ExamStudentImportController.java

@@ -71,7 +71,7 @@ public class ExamStudentImportController extends ControllerSupport {
 		File storeLocation = item.getStoreLocation();
 		String originalFilename = file.getOriginalFilename();
 
-		String suffix = originalFilename.substring(originalFilename.indexOf(originalFilename));
+		String suffix = originalFilename.substring(originalFilename.indexOf("."));
 		long batchId = System.currentTimeMillis();
 		String name = new StringBuilder().append(rootOrgId).append("_").append(examId).append("_")
 				.append(DateUtil.getNow(DatePatterns.YYYYMMDDHHMM)).toString();