src/main/java/ru/ulstu/grant/controller/GrantController.java

@@ -83,12 +83,7 @@ public class GrantController {
 
     @PostMapping(value = "/grant", params = "attachPaper")
     public String attachPaper(GrantDto grantDto) {
-        if (!grantDto.getPaperIds().isEmpty()) {
-            grantDto.getPapers().clear();
-            grantDto.setPapers(grantService.getGrantPapers(grantDto.getPaperIds()));
-        } else {
-            grantDto.getPapers().clear();
-        }
+        grantService.attachPaper(grantDto);
         return GRANT_PAGE;
     }
 

src/main/java/ru/ulstu/grant/service/GrantService.java

@@ -176,4 +176,12 @@ public class GrantService {
         return paperService.findAll();
     }
 
+    public void attachPaper(GrantDto grantDto) {
+        if (!grantDto.getPaperIds().isEmpty()) {
+            grantDto.getPapers().clear();
+            grantDto.setPapers(getGrantPapers(grantDto.getPaperIds()));
+        } else {
+            grantDto.getPapers().clear();
+        }
+    }
 }