提供在 $project 中使用 mongoDB 指定字段顺序的方法

Question

我正在尝试根据结果中特定顺序的字段 'Type' 从 Mongo 数据库中提取文档。结果被正确检索，但结果没有保留查询中给出的字段顺序。

我已经包含了下面的工作代码片段，有人可以帮助我如何根据我的代码片段更新等效的 Java 代码。

Mongo query is as below :- (Which retrieves data)
==========================================
    db.getCollection('elements').aggregate([
        {$match : {'Type' : {$eq : 'ALM_Project'}}},
        { $project:  {
            _id: 0,
            'ID' : 1,
            'Summary' : 1,
            'Created Date' : 1
          }},
        ])

Equivalent Java code is as below :-
==============================================================
 AggregateIterable<Document> documents = getMongoCollection()
        .aggregate(Arrays.asList(Aggregates.match(andQuery),
            Aggregates.project(Projections.fields(
                   Projections.include("ID", "Summary", "Created Date"),
                   Projections.exclude("_id")))));

Mongo query is as below :- (Added the fields preserving code)
===============================================================
db.getCollection('elements').aggregate([
{$match : {'Type' : {$eq : 'ALM_Project'}}},
{ $project:  {
    _id: 0,
    'ID' : 1,
    'Summary' : 1,
    'Created Date' : 1
  }},

 { "$project": {
        "ID": "$ID",
        "Summary": "$Summary",
        "Created Date": "$Created Date"
    }} 
])

Mongo 查询通过保留字段顺序完美运行。谁能告诉我如何基于此更新 java 代码。

Answer 1

您可以使用 MongoDB Compass 从管道输出 Java 代码。这是示例代码。

Arrays.asList(match(eq("Type", "ALM_Project")), 
  project(fields(excludeId(), 
  include("ID", "Summary", "Created Date"))), 
  project(computed("ID", "$ID"), 
  computed("Summary", "$Summary"), 
  computed("Created Date", "$Created Date")))

提供在 $project 中使用 mongoDB 指定字段顺序的方法

Provide way to specify field order in $project on using mongoDB

java

field

sql-order-by

mongodb

preserve