在 MongoDB/Java Spring Boot 中获取月数

Question

我在 mongodb 中有一个包含以下数据的集合：

集合名称：runState

runId: 1
startTime:2020-09-16T20:56:06.598+00:00
endTime:2020-09-16T20:57:09.196+00:00
product_action: org_rhel_oracle_install
Task: completed
ranBy:David

runId: 2
startTime:2021-01-11T20:56:06.598+00:00
endTime:2021-01-11T20:56:09.196+00:00
product_action: org_rhel_oracle_install
Task: completed
ranBy:John

runId: 2
startTime:2021-01-27T20:56:06.598+00:00
endTime:2021-01-27T20:56:09.196+00:00
product_action: org_rhel_oracle_install
Task: completed
ranBy:John

runId: 3
startTime:2021-01-11T20:56:06.598+00:00
endTime:2021-01-11T20:57:09.196+00:00
product_action: org_rhel_postgres_install
Task: completed
ranBy:John

runId: 4
startTime:2021-02-09T20:56:06.598+00:00
endTime:2021-02-09T20:57:09.196+00:00
product_action: org_rhel_oracle_install
Task: completed
ranBy:John

runId: 5
startTime:2021-02-09T20:56:06.598+00:00
endTime:2021-02-09T20:57:09.196+00:00
product_action: org_rhel_postgres_install
Task: completed
ranBy:John

runId: 6
startTime:2021-09-09T20:56:06.598+00:00
endTime:2021-09-09T20:57:09.196+00:00
product_action: org_rhel_postgres_install
Task: completed
ranBy:John

runId: 7
startTime:2022-01-09T20:56:06.598+00:00
endTime:2022-01-09T20:57:09.196+00:00
product_action: org_rhel_oracle_install
Task: completed
ranBy:David

runId: 8
startTime:2022-01-10T20:56:06.598+00:00
endTime:2022-01-10T20:57:09.196+00:00
product_action: org_rhel_oracle_install
Task: failed
ranBy:David

我希望输出作为任务完成的每个产品的过去 12 个月（2021 年 1 月至 2022 年 1 月）的计数（产品可从 product_action 获取）

输出应采用以下格式：

{
"_id" : "postgres",
completed: [
        {
            "month" : "FEB-2021",
            "count" : 1
        },
        {
            "month" : "SEP-2021",
            "count" : 1
        },
        {
            "month" : "JAN-2021",
            "count" : 1
        }
]
},
{
"_id" : "oracle",
    "completed" : [
        {
            "month" : "FEB-2021",
            "count" : 1
        },
        {
            "month" : "JAN-2021",
            "count" : 2
        }
    ]
}

我从下面开始，但不知道如何像上面那样按月计算。

{"product_action":{$regex:"postgres|oracle"},"Task":"completed"}

由于这对我来说是新的，有人可以帮助我进行 mongo DB 查询以获取结果以及在 Java springboot 中实现这一目标的代码吗？

我尝试使用聚合的 Java 代码，但这并没有产生我想要的结果。

Aggregation agg = Aggregation.newAggregation(
                Aggregation.project("endTime","Task","product_action").and(DateOperators.Month.monthOf("endTime")).as("month"),
                Aggregation.match(Criteria.where("product_action").regex("postgres|oracle").and("Task").is("completed")
                        .and("endTime").gte(parseDate("2021-02-01"))),
                Aggregation.group("month","Task").count().as("count")
                );

Answer 1

试穿一下尺寸：

db.foo.aggregate([
    // Get easy stuff out way. Filter for the desired date range and only
    // those items that are complete:
    {$match: {$and: [
        {"endTime":{$gte:new ISODate("2021-01-01")}},
        {"endTime":{$lt:new ISODate("2022-01-01")}},
        {"Task":"completed"}
    ]} }

    // Now group by product and date expressed as month-year.  The product
    // is embedded in the field value so there are a few approaches to digging
    // it out.  Here, we split on underscore and take the [2] item.
    ,{$group: {_id: {
        p: {$arrayElemAt:[{$split:["$product_action","_"]},2]},
        d: {$dateToString: {date: "$endTime", format: "%m-%Y"}}
               },
               n: {$sum: 1}
    }}

    // The OP seeks to make the date component nested inside the product
    // instead of having it as a two-part grouping.  We will "regroup" and
    // create an array.  This is slightly different than the format indicated
    // by the OP but values as keys (e.g. "Jan-2021: 2") is in general a 
    // poor idea so instead we construct an array of proper name:value pairs.
    ,{$group: {_id: '$_id.p',
               completed: {$push: {d: '$_id.d', n: '$n'}}
    }}

]);

产生

{
    "_id" : "postgres",
    "completed" : [
        {
            "d" : "02-2021",
            "n" : 1
        },
        {
            "d" : "09-2021",
            "n" : 1
        },
        {
            "d" : "01-2021",
            "n" : 1
        }
    ]
}
{
    "_id" : "oracle",
    "completed" : [
        {
            "d" : "02-2021",
            "n" : 1
        },
        {
            "d" : "01-2021",
            "n" : 2
        }
    ]
}

更新

之前出现过 $dateToString 函数没有格式参数来生成一个月的 3 个字母缩写，例如JAN（或长格式，例如January）。排序仍然适用于01-2021,02-2021,04-2021 与JAN-2021,FEB-2021,APR-2021，但如果确实需要直接从数据库而不是在客户端代码中进行后处理这样的输出，那么第二组将替换为$sort 和$group如下：

    // Ensure the NN-YYYY dates are going in increasing order.  The product
    // component _id.p does not matter here -- only the dates have to be
    // increasing.  NOTE:  This is OPTIONAL with respect to changing
    // NN-YYYY into MON-YYYY but almost always the follow on question is
    // how to get the completed list in date order...
    ,{$sort: {'_id.d':1}}

    // Regroup as before but index the NN part of NN-YYYY into an
    // array of 3 letter abbrevs, then reconstruct the string with the
    // dash and the year component.  Remember: the order of the _id 
    // in the doc stream coming out of $group is not deterministic
    // but the array created by $push will preserve the order in
    // which it was pushed -- which is the date-ascending sorted order
    // from the prior stage.
    ,{$group: {_id: '$_id.p',
               completed: {$push: {
                   d: {$concat: [
                       {$arrayElemAt:[ ['JAN','FEB','MAR',
                                        'APR','MAY','JUN',
                                        'JUL','AUG','SEP',
                                        'OCT','NOV','DEC'],
                       // minus 1 to adjust for zero-based array:
                       {$subtract:[{$toInt: {$substr:['$_id.d',0,2]}},1]}
                             ]},
                       "-",
                       {$substr:['$_id.d',3,4]}
                   ]},
                   n: '$n'}}
              }}

产生：

{
    "_id" : "postgres",
    "completed" : [
        {
            "d" : "JAN-2021",
            "n" : 1
        },
        {
            "d" : "FEB-2021",
            "n" : 1
        },
        {
            "d" : "SEP-2021",
            "n" : 1
        }
    ]
}
{
    "_id" : "oracle",
    "completed" : [
        {
            "d" : "JAN-2021",
            "n" : 2
        },
        {
            "d" : "FEB-2021",
            "n" : 1
        }
    ]
}

至于将其转换为 Java，有几种方法，但除非需要大量的编程控制，否则将查询捕获为 Java 字符串中的“宽松 JSON”（键周围不需要引号）并调用 @987654333 @ 似乎是最简单的方法。可以在此处找到包含辅助函数和适当的 Java 驱动程序调用的完整示例：https://moschetti.org/rants/mongoaggcvt.html，但它的要点是：

    private static class StageHelper {
        private StringBuilder txt;

        public StageHelper() {
            this.txt = new StringBuilder();
        }

        public void add(String expr, Object ... subs) {
            expr.replace("'", "\""); // This is the helpful part.                            
            if(subs.length > 0) {
                expr = String.format(expr, subs);  // this too                               
            }
            txt.append(expr);
        }
        public Document fetch() {
            Document b = Document.parse(txt.toString());
            return b;
        }
    }

    private List<Document> makePipeline() {
        List<Document> pipeline = new ArrayList<Document>();

        StageHelper s = new StageHelper();
        s.add("{$match: {$and: [ ");

        // Note use of EJSON here plus string substitution of dates:                         
        s.add("  {endTime:{$gte: {$date: '%s'}} }", "2021-01-01");
        s.add("  {endTime:{$lt: {$date: '%s'}} }", "2022-01-01");

        s.add("  {Task:'completed'} ");
        s.add("]} } ");
        pipeline.add(s.fetch());

        s = new StageHelper();
        s.add("{$group: {_id: { ");
        s.add("  p: {$arrayElemAt:[{$split:['$product_action','_']},2]}, ");
        s.add("  d: {$dateToString: {date: '$endTime', 'format': '%m-%Y'}} ");
        s.add("  }, ");
        s.add("  n: {$sum: 1}  ");
        s.add("}} ");
        pipeline.add(s.fetch());

        s = new StageHelper();
        s.add("{$sort: {'_id.d':1}} ");
        pipeline.add(s.fetch());

        s = new StageHelper();
        s.add("{$group: {_id: '$_id.p', ");
        s.add("        completed: {$push: { ");
        s.add("            d: {$concat: [ ");
        s.add("                {$arrayElemAt:[ ['JAN','FEB','MAR', ");
        s.add("                                 'APR','MAY','JUN', ");
        s.add("                                 'JUL','AUG','SEP', ");
        s.add("                                 'OCT','NOV','DEC'], ");
        s.add("                {$subtract:[{$toInt: {$substr:['$_id.d',0,2]}},1]} ");
        s.add("                      ]}, ");
        s.add("                '-', ");
        s.add("                {$substr:['$_id.d',3,4]} ");
        s.add("            ]}, ");
        s.add("            n: '$n'}} ");
        s.add("       }} ");
        pipeline.add(s.fetch());

    return pipeline;
    }
...
    import com.mongodb.client.MongoCursor;
    import com.mongodb.client.AggregateIterable;

    AggregateIterable<Document> output = coll.aggregate(pipeline);
    MongoCursor<Document> iterator = output.iterator();
    while (iterator.hasNext()) {
            Document doc = iterator.next();