优化dbref性能

cqb-paper/src/main/java/com/qmth/cqb/paper/model/PaperDetail.java

@@ -13,7 +13,7 @@ public class PaperDetail implements Serializable,Comparable<PaperDetail> {
     @Id
     private String id;
 
-    @DBRef
+    @DBRef(lazy = true)
     private Paper paper;// 关联的试卷
 
     private Integer number;// 大题序号

cqb-paper/src/main/java/com/qmth/cqb/paper/model/PaperDetailUnit.java

@@ -23,7 +23,7 @@ public class PaperDetailUnit implements Serializable, Comparable<PaperDetailUnit
     @Id
     private String id;
 
-    @DBRef
+    @DBRef(lazy = true)
     private Paper paper;// 关联的试卷
 
     private Integer number;// 小题序号
@@ -32,12 +32,12 @@ public class PaperDetailUnit implements Serializable, Comparable<PaperDetailUnit
 
     private List<Double> subScoreList;// 对应套题的情况下，各子题的分数分布
 
-    @DBRef
+    @DBRef(lazy = true)
     private PaperDetail paperDetail;// 关联的大题
 
     private QuesStructType questionType;// 小题类型
 
-    @DBRef
+    @DBRef(lazy = true)
     private Question question;// 关联试题
 
     /**