//插入時轉換
public void put(MongoPersistentProperty prop, Object value) {
 Assert.notNull(prop, "MongoPersistentProperty must not be null!");
 String fieldName = prop.getFieldName();
 if (!fieldName.contains(".")) {
  dbObject.put(fieldName, value);
  return;
 }
 Iterator<String> parts = Arrays.asList(fieldName.split("\\.")).iterator();
 DBObject dbObject = this.dbObject;
 while (parts.hasNext()) {
  String part = parts.next();
  if (parts.hasNext()) {
   dbObject = getOrCreateNestedDbObject(part, dbObject);
  } else {
   dbObject.put(part, value);
  }
 }
}

//查詢時轉換
public Object get(MongoPersistentProperty property) {
 String fieldName = property.getFieldName();
 if (!fieldName.contains(".")) {
  return this.dbObject.get(fieldName);
 }
 Iterator<String> parts = Arrays.asList(fieldName.split("\\.")).iterator();
 Map<String, Object> source = this.dbObject;
 Object result = null;
 while (source != null && parts.hasNext()) {
  result = source.get(parts.next());
  if (parts.hasNext()) {
   source = getAsMap(result);
  }
 }
 return result;
}

//判斷值是否為空
public boolean hasValue(MongoPersistentProperty property) {
 Assert.notNull(property, "Property must not be null!");
 String fieldName = property.getFieldName();
 if (!fieldName.contains(".")) {
  return this.dbObject.containsField(fieldName);
 }
 String[] parts = fieldName.split("\\.");
 Map<String, Object> source = this.dbObject;
 Object result = null;
 for (int i = 1; i < parts.length; i++) {
  result = source.get(parts[i - 1]);
  source = getAsMap(result);
  if (source == null) {
   return false;
  }
 }
 return source.containsKey(parts[parts.length - 1]);
}

{
 "_id": ObjectId("5bae00765500af6307755111"),
 "name": "java",
 "age": 26,
 "A.B": "nnnn"
}

@Field("A.B")
@JSONField(serialzeFeatures = SerializerFeature.DisableCircularReferenceDetect)
private Integer ab;　　

//查詢時轉換
public Object get(MongoPersistentProperty property) {
 String fieldName = property.getFieldName();
 return this.dbObject.get(fieldName);
}
 
//判斷值是否為空
public boolean hasValue(MongoPersistentProperty property) {
 Assert.notNull(property, "Property must not be null!");
 String fieldName = property.getFieldName();
 return this.dbObject.containsField(fieldName);
}