优化标记试卷查询时由于异常数据导致的空指针异常

stmms-web/src/main/java/cn/com/qmth/stmms/admin/exam/TagController.java

@@ -79,10 +79,11 @@ public class TagController extends BaseParameterController {
             List<ExamStudent> list = new LinkedList<ExamStudent>();
             for (MarkLibrary library : query.getResult()) {
                 ExamStudent student = studentService.findById(library.getStudentId());
-                student.setSheetUrls(PictureUrlBuilder.getSheetUrls(examId, library.getCampusId(),
-                        student.getSubjectCode(), student.getExamNumber(), student.getSheetCount()));
-                student.setMarkTime(DateUtils.formatDateTime(library.getMarkerTime()));
-
+                if(student != null){
+                    student.setSheetUrls(PictureUrlBuilder.getSheetUrls(examId, library.getCampusId(),
+                            student.getSubjectCode(), student.getExamNumber(), student.getSheetCount()));
+                    student.setMarkTime(DateUtils.formatDateTime(library.getMarkerTime()));
+                }
                 list.add(student);
             }
             model.addAttribute("resultList", list);