与 getMappedResults() 一起使用时查找无法正常工作

Question

我有以下代码，getRawResult 和 getMappedResult 的答案不同。我想知道如何在 mappedResults 中包含 user 和 place 对象。

     // This methd searches the given string in reviews of the given country
                    
        MatchOperation matchRegion = Aggregation.match(Criteria.where("Country").is("Germany"));
                    
        //To match the review
        TextCriteria criteria = TextCriteria.forDefaultLanguage().matchingAny(text);
        MatchOperation match = Aggregation.match(criteria);         

        GroupOperation group = Aggregation.group("place.place_name").push("$$ROOT").as("reviews").sum("textScore")
                .as("score");

        ProjectionOperation project = Aggregation
                .project("some_point", "place", "user", "date")
                .andExpression("{$meta: \"textScore\"}").as("textScore");               
    
        SortOperation sortByScore = Aggregation.sort(Sort.Direction.DESC, "score");

        Aggregation aggregation = Aggregation.newAggregation(match,Aggregation.lookup("place","placeId","_id","place"),
                Aggregation.unwind("place"),Aggregation.lookup("user","userId","_id","user"),
                Aggregation.unwind("user") , matchRegion, project, group, sortByScore);

        
        AggregationResults<ReviewAggrResults> results = mongoTemplate.aggregate(aggregation,
                mongoTemplate.getCollectionName(Review.class), ReviewAggrResults.class);    
        
        List<ReviewAggrResults> result = results.getMappedResults();
            
        Object object = mongoTemplate.aggregate(aggregation, Review.class, Object.class).getRawResults();


        Print.print("result object rawResults", object); 
        Print.print("result reviewaggrresult: ", result);
        

使用上面的代码，getRawResults 和 ReviewAggrResult 的打印结果如下：

原始结果：

  {
      "results" : [ {
        "_id" : "ibis Heidelberg, Willy-Brandt-Platz 3, 69115 Heidelberg, Germany",
        "reviews" : [ {
          "_id" : {
            "timestamp" : 1610817567,
            "date" : 1610817567000
          },
          "some_point" : "something",         
          "date" : "Sat Jan 16 18:19:27 CET 2021",
          "place" : {
            "_id" : {
              "timestamp" : 1610817567,
              "date" : 1610817567000
            },
            "place_name" : "ibis Heidelberg, Willy-Brandt-Platz 3, 69115 Heidelberg, Germany",
            "country" : "Germany",
          },
          "user" : {
            "_id" : {
              "timestamp" : 1610817549,
              "date" : 1610817549000
            },
            "firstname" : "test1first",
            "lastname" : "test1last",
          },
          "textScore" : 5.25
        } ],
        "score" : 5.25
      } ],
      "ok" : 1.0
    }

映射结果：

[ {
  "reviews" : [ {
    "id" : "6003201f98afbc730e4f58eb",
    "some_point" : "something",
    "placeId" : null,
    "userId" : null,
    "date" : "Sat Jan 16 18:19:27 CET 2021",
    "textScore" : 5.25
  } ],
  "id" : "ibis Heidelberg, Willy-Brandt-Platz 3, 69115 Heidelberg, Germany",
  "userId" : null,
  "user" : null,
  "score" : 5.25
} ]

为什么它们不同？原始结果是正确的，但是当它被映射时，地点和用户对象被删除。我怎样才能将它们也包含在 mappedResult 中？

Answer 1

getMappedResults() 为您提供映射类和聚合结果的直接映射。看看这里有什么问题。当你拿getRawResult()为例，我只会拿place

"place" : {
    "_id" : {
      "timestamp" : 1610817567,
      "date" : 1610817567000
    },
    "place_name" : "ibis Heidelberg, Willy-Brandt-Platz 3, 69115 Heidelberg, Germany",
    "country" : "Germany",
}

place 是一个对象，它有_id、place_name 和country。但是在您的映射类Review 中，您只有placeId，结果没有提供。所以它不能做点对点的映射。你能做的是

class Place{
    ObjectId _id;
    String place_name;
    String country;
    //Constrtuctors, Getters, Setters
}

在你的复习课上，

class Review{
    // other fields
    Place place;
}

您也需要对其他对象或数组执行相同的操作。这应该工作