优化删除试卷答案文件

sstudy/src/main/java/com/xhkjedu/sstudy/service/paper/PaperService.java

@@ -276,7 +276,7 @@ public class PaperService {
             for (int i = 0; i < pfilelist.size(); i++) {
                 TPaperFile pf = pfilelist.get(i);
                 resourceUrls.add(pf.getFilepath());
-                if (i == 0) {
+                if (!resourceUrls.contains(pf.getSourcepath())) {
                     resourceUrls.add(pf.getSourcepath());
                 }
             }