在 Spring MongoDB 的 ReplaceRoot 管道阶段使用 $mergeObjects

Question

我希望将此片段复制到 Java 代码中：

db.getCollection('admins_comptes_client_ceov4').aggregate([
{$lookup: {from: "contrats_ceov4",localField: "CUSTOMERNUMBER",foreignField: "CUSTOMERNUMBER",as: "arrayForeignObject"}
{$unwind: { path: "$arrayForeignObject", preserveNullAndEmptyArrays: true}},
{$replaceRoot: { newRoot: { $mergeObjects: [ "$arrayForeignObject", "$$ROOT" ] } }},
{ $project: { "arrayForeignObject": 0, "_id": 0 } },
{ $out: "aggregate" }])

到目前为止我在这里：

 AggregationOperation lookup = Aggregation.lookup(fromCollection, localField, toMatchWith, "arrayForeignObject");
 AggregationOperation unwind = Aggregation.unwind("arrayForeignObject", true);
AggregationOperation replaceRoot = Aggregation.replaceRoot(Aggregation.ROOT);
AggregationOperation project = Aggregation.project("arrayForeignObject").andExclude("_id");
AggregationOperation out = Aggregation.out("aggregate");

Aggregation aggregation = Aggregation.newAggregation(lookup, replaceRoot, unwind, project, out);

mongoTemplate.aggregate(aggregation, initialCollection, AggregateModel.class);

我对以下几点有疑问： {$replaceRoot: { newRoot: { $mergeObjects: [ "$arrayForeignObject", "$$ROOT" ] } } 我无法成功创建合并对象。 使用以下 java sn-p，AggregationOperation 的结果是：

"$replaceRoot" : { "newRoot" : "$arrayForeignObject" } 

当我执行这个 java sn-p 时，我最终得到了一个新集合，里面只有一个外部数组和一个 _id 字段。

有没有人已经遇到过这个问题，可以帮忙吗？ 弗里格0

Answer 1

这里有几个问题。使用 2.1.0 Release Spring Mongodb jar。

AggregationOperation replaceRoot = Aggregation.replaceRoot().withValueOf(ObjectOperators.valueOf("arrayForeignObject").mergeWith(Aggregation.ROOT));
AggregationOperation project = Aggregation.project().andExclude("_id", "arrayForeignObject");
Aggregation aggregation = Aggregation.newAggregation(lookup, unwind, replaceRoot, project, out);

对于spring mongodb的低版本

AggregationOperation replaceRoot = ReplaceRootOperation.builder().withDocument("$mergeObjects", Arrays.asList("$arrayForeignObject", Aggregation.ROOT));
AggregationOperation project = Aggregation.project().andExclude("_id", "arrayForeignObject");
Aggregation aggregation = Aggregation.newAggregation(lookup, unwind, replaceRoot, project, out);