优化 在管理员查看试卷原卷时由于数据异常导致的空指针异常

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

@@ -1,5 +1,6 @@
 package cn.com.qmth.stmms.admin.exam;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.List;
 
@@ -34,17 +35,18 @@ public class MarkTrackController extends BaseParameterController {
 
 	/**
 	 * 
-	 * @param request
-	 * @param model
-	 * @param query
+	 * @param studentId
 	 * @return
 	 */
 	@ResponseBody
 	@RequestMapping
 	public HashMap<String, Object> list(Integer studentId) {
 		List<MarkTrack> markTracks = markTrackService.findByStudentId(studentId);
-		MarkLibrary markLibrary=markLibraryService.findByStudentId(studentId);
-		List<String> picUrls = PictureUrlBuilder.getSliceUrls(markLibrary.getExamId(), markLibrary.getCampusId(), markLibrary.getSubjectCode(), markLibrary.getExamNumber(), markLibrary.getPicStart(), markLibrary.getPicCount());
+  		MarkLibrary markLibrary=markLibraryService.findByStudentId(studentId);
+        List<String> picUrls = new ArrayList<String>();
+		if(markLibrary != null){
+          picUrls = PictureUrlBuilder.getSliceUrls(markLibrary.getExamId(), markLibrary.getCampusId(), markLibrary.getSubjectCode(), markLibrary.getExamNumber(), markLibrary.getPicStart(), markLibrary.getPicCount());
+		}
 		HashMap<String, Object> map = new HashMap<String, Object>();
 		map.put("picUrls",picUrls);
 		map.put("markTracks", markTracks);