diff --git a/servers/boe-server-all/src/main/java/com/xboe/school/study/service/impl/StudyExamServiceImpl.java b/servers/boe-server-all/src/main/java/com/xboe/school/study/service/impl/StudyExamServiceImpl.java
index 1d3085e5..21840e74 100644
--- a/servers/boe-server-all/src/main/java/com/xboe/school/study/service/impl/StudyExamServiceImpl.java
+++ b/servers/boe-server-all/src/main/java/com/xboe/school/study/service/impl/StudyExamServiceImpl.java
@@ -24,7 +24,6 @@ import org.springframework.stereotype.Service;
 import javax.annotation.Resource;
 import javax.transaction.Transactional;
 import java.time.LocalDateTime;
-import java.util.ArrayList;
 import java.util.List;
 
 @Slf4j
@@ -171,11 +170,11 @@ public class StudyExamServiceImpl implements IStudyExamService{
 	 */
 	@Override
 	public List<StudyExam> getByCourseIdAndContentId(String courseId, String contentId) {
-		if (courseId == null) {
-			throw new IllegalArgumentException("courseId must not be null");
+		if (StringUtils.isEmpty(courseId)) {
+			throw new IllegalArgumentException("课程id不能为空");
 		}
 		IFieldFilter filter = FieldFilters.eq("courseId", courseId);
-		if (contentId != null) {
+		if (StringUtils.isNotEmpty(contentId)) {
 			filter = FieldFilters.and(filter, FieldFilters.eq("contentId", contentId));
 		}
 		return dao.findList(OrderCondition.desc("id"), filter);