写错了一行。。

src/main/java/edu/nju/service/ReviewPaperService.java

@@ -122,6 +122,7 @@ public class ReviewPaperService {
                 if(reviewPaperDao.findPaper(paperId)!=null){
                     object.put("status","success");
                     object.put("paperId",paperId);
+                    return object;
                 }
             }
             ReviewPaperVO reviewPaperVO = getReviewPaperVO(jsonObject);