如何在带有spring数据mongodb的java中使用$ lookup阶段？

Question

直到最后一个版本的spring我已经看到很多堆栈溢流问题，这表明在spring-data-mongodb中没有对此操作的支持在新的spring-data-mongodb 1.10.0中是否支持此操作

db.orders.aggregate([
        {
          $lookup:
            {
              from: "inventory",
              localField: "item",
              foreignField: "sku",
              as: "inventory_docs"
            }
       }
    ])

Answer 1

自1.9版以来一直有查找支持。

LookupOperation lookupOperation = LookupOperation.newLookup().
                                   from("inventory").
                                   localField("item").
                                   foreignField("sku").
                                   as("inventory_docs");
Aggregation aggregation = Aggregation.newAggregation(lookupOperation);
List<BasicDBObject> results = mongoOperations.aggregate(aggregation, "orders", BasicDBObject.class).getMappedResults();