关于源代码：org.bson.Document无法转换为com.mongodb.DBObject

Question

我有一个问题。我使用2.x版本，请查看源代码。MappingMongoConverter.class：

@Nullable
private <S> S read(TypeInformation<S> type, @Nullable Bson bson, ObjectPath path) {
    if (null == bson) {
        return null;
    } else {
        TypeInformation<? extends S> typeToUse = this.typeMapper.readType(bson, type);
        Class<? extends S> rawType = typeToUse.getType();
        if (this.conversions.hasCustomReadTarget(bson.getClass(), rawType)) {
            return this.conversionService.convert(bson, rawType);
        } else if (DBObject.class.isAssignableFrom(rawType)) {
            return bson;
        } else if (Document.class.isAssignableFrom(rawType)) {
            return bson;
        } else if (typeToUse.isCollectionLike() && bson instanceof List) {
            return this.readCollectionOrArray(typeToUse, (List)bson, path);
        } else if (typeToUse.isMap()) {
            return this.readMap(typeToUse, bson, path);
        } else if (bson instanceof Collection) {
            throw new MappingException(String.format("Cannot convert %1$s of type %2$s into an instance of %3$s! Implement a custom Converter<%2$s, %3$s> and register it with the CustomConversions. Parent object was: %4$s", bson, BasicDBList.class, typeToUse.getType(), path));
        } else if (typeToUse.equals(ClassTypeInformation.OBJECT)) {
            return bson;
        } else {
            Document target = bson instanceof BasicDBObject ? new Document((BasicDBObject)bson) : (Document)bson;
            MongoPersistentEntity<?> entity = (MongoPersistentEntity)this.mappingContext.getPersistentEntity(typeToUse);
            if (entity == null) {
                throw new MappingException(String.format("Expected to read Document %s into type %s but didn't find a PersistentEntity for the latter!", target, typeToUse.getType()));
            } else {
                return this.read((MongoPersistentEntity)this.mappingContext.getRequiredPersistentEntity(typeToUse), target, path);
            }
        }
    }
}

此行：

else if (DBObject.class.isAssignableFrom(rawType)) {
            return bson;
        }

当我尝试将响应转换为DBObject时，这将返回bson.class（Document.class），例如：

List<DBObject> userList = mongoTemplate.findAll(DBObject.class, "user_info");

“ userList”元素实际上是Document.class。因此，在执行此代码时：

DBObject obj = userList.get(1)

这是一个问题：“ org.bson.Document无法转换为com.mongodb.DBObject。”

对吗？为什么我执行：mongoTemplate.findAll（DBObject.class，“ user_info”），我将使用List的Document.class？不是列表的DBObject.class？