how to use $lookup stage in java with spring data mongodb? [duplicate]

问题

This question already has an answer here:

lookup in mongodb aggregation (1 answer)

Closed last year.

Up to last version of spring i have seen lot of stack over flow questions which shows there is no support for this operation in spring-data-mongodb is there any support for this operation in new spring-data-mongodb 1.10.0

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

回答1:

Lookup support has been there since 1.9 version.

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();

来源：https://stackoverflow.com/questions/42452764/how-to-use-lookup-stage-in-java-with-spring-data-mongodb