在 Spring.Mongodb 中按日期间隔聚合 Mongo 模板

Question

I need to aggregate some data using java and Mongodb.

So my JS script it's that:

db.post.aggregate([
    {$match: {date: {$gte: ISODate("2019-08-28T17:50:09.803Z"), $lte: ISODate("2019-12-03T21:45:51.412+00:00")}}},
    {$project: {author: 1, _id: 0}},
    {$group: {_id: "$author", count: {$sum:1}}}])

And my Java Code using spring+java is:

    Aggregation aggregation =
            newAggregation(
                    match(Criteria.where("date")
                            .lte(dynamicQuery.getEndDate())
                            .gte(dynamicQuery.getInitDate())),
                    project("author").andExclude("_id"),
                    group("author")
                            .count()
                            .as("total"));

    AggregationResults<Post> result = mongoTemplate.aggregate(aggregation,Post.class, PostSummary.class);
    List<Post> map = result.getMappedResults();

And I need to aggregate the sum of documents by authorId. My code returns the user code and no sum of documents.

And we have 2 Collections:

@EqualsAndHashCode(of = "id")
//TODO: Change the @Data to the properly scenario, we don't need 
setters in this class anymore.
@Data
@Document (collection = "user")
//TODO: Change collection name to post, because collection are a group 
of elements
public class User {

  @Id
  private String id;

  private String name;

  private String username;

  @Email
  private String email;

  private String imageUrl;

  private String providerId;

  private LocalDateTime firstAccess;

}

Post Document:

@Data
@Document(collection = "post")
//TODO: Change collection name to post, because collection are a group of elements
public class Post {
   public static final String AUTHOR_FIELD_NAME = "author";
   public static final String DATE_FIELD_NAME = "date";

   @Id
   private String id;
   private String content;

   @DBRef(lazy = true)
   @Field(AUTHOR_FIELD_NAME)
   private User author;

   @DateTimeFormat(iso = DateTimeFormat.ISO.DATE_TIME)
   @Field(DATE_FIELD_NAME)
   private LocalDateTime date;

   public Post(String content, User author, LocalDateTime date) {
       this.content = content;
       this.author = author;
       this.date = date;
    }
  }

Answer 1

I have one solution, but I do not know if it is a better solution, so, let's go.

Because the Entity represented inside the Post Domain is one DBRef, the MongoDB does not parse the entire Stringo to the PostSummary.Class

    @Getter
    @Setter
    public class PostSummary {
        private User author;
        private int count;
    }

So, for the solution, I only parse the @Id in the author, and it's working. So If anyone has a better solution we have one solution now.

And should be like this:

  @Getter
  @Setter
  public class PostSummary {
    @Id
    private User author;
    private int count;
}