java - Mongo 模板在 Spring.Mongodb 中按日期间隔聚合

Question

我需要使用 java 和 Mongodb 聚合一些数据。

所以我的 JS 脚本是这样的:

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}}}])

我使用 spring+java 的 Java 代码是:

    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();

我需要按authorId 聚合文档的总和。我的代码返回用户代码，但不返回文档总和。

我们有 2 个系列:

@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;

}

发布文档:

@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

我有一个解决方案，但我不知道这是否是更好的解决方案，所以，我们走吧。

由于 Post Domain 内表示的实体是一个 DBRef，因此 MongoDB 不会将整个 Stringo 解析为 PostSummary.Class

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

因此，对于解决方案，我只解析作者中的@Id，并且它有效。因此，如果有人有更好的解决方案，我们现在就有一个解决方案。

应该是这样的:

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