與嵌套數組的投影創建春數據彙總查詢

Question

這裏是我的文件看起來像：

{ 
"_id" : ObjectId("583cb6bcce047d1e68339b64"), 
"variantDetails" : [ 
    { 
     "variants" : { 
      "_" : "_" 
     }, 
     "sku" : "069563-59690" 
    }, 
    { 
     "variants" : { 
      "size" : "35" 
     }, 
     "sku" : "069563-59690-35", 
     "barcode" : "809702246941" 
    }, 
    { 
     "variants" : { 
      "size" : "36" 
     }, 
     "sku" : "069563-59690-36", 
     "barcode" : "809702246958" 
    } 
    ...... 
] } 

而且我想用一個複雜的聚合查詢是這樣的：

db.getCollection('product').aggregate([ 
    { '$match': { 'variantDetails.sku': { '$in': ['069563-59690', '069563-59690-36', '069563-59690-37', '511534-01001'] } } }, 
    { '$project': {'_id': 1, 'variantDetails': 1, 'variantLength': { '$size': '$variantDetails' } } }, 
    { '$unwind': '$variantDetails' }, 
    { '$match': { 'variantDetails.sku': { '$in': ['069563-59690', '069563-59690-36', '069563-59690-37', '511534-01001'] } } }, 
    { '$match': { '$or': [ 
     {'variantLength': { '$ne': 1 }, 'variantDetails.variants._': { '$ne': '_' } }, 
     {'variantLength': 1 } 
    ] } }, 
    { '$group': { '_id': '$_id', 'variantDetails': { '$push': '$variantDetails' } } }, 
    { '$project': {'_id': 1, 'variantDetails.sku': 1, 'variantDetails.barcode': 1} } 
]) 

這裏是我的Java代碼：

final Aggregation agg = Aggregation.newAggregation(
      Aggregation.match(Criteria.where("variantDetails.sku").in(skus)), 
      Aggregation.project("_id", "variantDetails").and("variantDetails").project("size").as("variantLength"), 
      Aggregation.unwind("variantDetails"), 
      Aggregation.match(Criteria.where("variantDetails.sku").in(skus)), 
      Aggregation.match(new Criteria().orOperator(Criteria.where("variantLength").is(1), Criteria.where("variantLength").ne(1).and("variantDetails.variants._").is("_"))), 
      Aggregation.group("_id").push("variantDetails").as("variantDetails"), 
      Aggregation.project("_id", "variantDetails.sku", "variantDetails.barcode") 
      ); 

    final AggregationResults<Product> result = this.mongo.aggregate(agg, this.mongo.getCollectionName(Product.class), Product.class); 
    return result.getMappedResults(); 

的問題是，春天翻譯

Aggregation.project("_id", "variantDetails.sku", "variantDetails.barcode") 

要

{ "$project" : { "_id" : 1 , "sku" : "$variantDetails.sku" , "barcode" : "$variantDetails.barcode"} 

但我期待

{ '$project': {'_id': 1, 'variantDetails.sku': 1, 'variantDetails.barcode': 1} } 

可能有人讓我知道如何去彌補？

Answer 1

您只需在投影操作中將標籤指定爲別名，因爲彈簧提供的默認值不匹配。使用Spring 1.8.5版本

Aggregation.project("_id") 
        .and(context -> new BasicDBObject("$arrayElemAt", Arrays.asList("variantDetails.sku", 0))).as("variantDetails.sku") 
        .and(context -> new BasicDBObject("$arrayElemAt", Arrays.asList("variantDetails.barcode", 0))).as("variantDetails.barcode"));