使用管道聚合的 Spring Data MongoDB 查找

问题描述

如何将以下 MongoDB 查询转换为我的 Java Spring 应用程序使用的查询?我找不到将 pipeline 与提供的 lookup 方法.

How would I convert the following MongoDB query into a query to be used by my Java Spring application? I can't find a way to use pipeline with the provided lookup method.

这是我尝试转换的查询.我还想指出，我没有使用 $unwind，因为我希望 deliveryZipCodeTimings 作为返回对象中的分组集合.

Here is the query I am attempting to convert. I also want to note that I didn't use $unwind as I wanted the deliveryZipCodeTimings to stay as a grouped collection in the return object.

db.getCollection('fulfillmentChannel').aggregate([
    {
        $match: {
            "dayOfWeek": "SOME_VARIABLE_STRING_1"
        }
    },
    {
        $lookup: {
            from: "deliveryZipCodeTiming",
            let: { location_id: "$fulfillmentLocationId" },
            pipeline: [{
                $match: {
                    $expr: {
                        $and: [
                            {$eq: ["$fulfillmentLocationId", "$$location_id"]},
                            {$eq: ["$zipCode", "SOME_VARIABLE_STRING_2"]}
                        ]
                    }
                }
            },
            {
                $project: { _id: 0, zipCode: 1, cutoffTime: 1 }
            }],
            as: "deliveryZipCodeTimings"
        }
    },
    {
        $match: {
            "deliveryZipCodeTimings": {$ne: []}
        }
    }
])

推荐答案

基于@dnickless 提供的信息，我能够解决这个问题.我将发布完整的解决方案，希望将来对其他人有所帮助.

Building upon the info given by @dnickless, I was able to solve this. I'll post the complete solution in the hopes it helps someone else in the future.

我正在使用 mongodb-driver:3.6.4

首先，我必须创建一个自定义聚合操作类，以便我可以传入一个自定义 JSON mongodb 查询以用于聚合操作.这将允许我在 $lookup 中使用 pipeline，而我正在使用的驱动程序版本不支持.

First, I had to create a custom aggregation operation class so that I could pass in a custom JSON mongodb query to be used in the aggregation operation. This will allow me to use pipeline within a $lookup which is not supported with the driver version I am using.

public class CustomProjectAggregationOperation implements AggregationOperation {
    private String jsonOperation;

    public CustomProjectAggregationOperation(String jsonOperation) {
        this.jsonOperation = jsonOperation;
    }

    @Override
    public Document toDocument(AggregationOperationContext aggregationOperationContext) {
        return aggregationOperationContext.getMappedObject(Document.parse(jsonOperation));
    }
}

现在我们已经能够将自定义 JSON 查询传递到我们的 mongodb spring 实现中，剩下的就是将这些值插入到 TypedAggregation 查询.

Now that we have the ability to pass a custom JSON query into our mongodb spring implementation, all that is left is to plug those values into a TypedAggregation query.

public List<FulfillmentChannel> getFulfillmentChannels(
    String SOME_VARIABLE_STRING_1,
    String SOME_VARIABLE_STRING_2) {

    AggregationOperation match = Aggregation.match(
            Criteria.where("dayOfWeek").is(SOME_VARIABLE_STRING_1));
    AggregationOperation match2 = Aggregation.match(
            Criteria.where("deliveryZipCodeTimings").ne(Collections.EMPTY_LIST));
    String query =
            "{ $lookup: { " +
                    "from: 'deliveryZipCodeTiming'," +
                    "let: { location_id: '$fulfillmentLocationId' }," +
                    "pipeline: [{" +
                    "$match: {$expr: {$and: [" +
                    "{ $eq: ['$fulfillmentLocationId', '$$location_id']}," +
                    "{ $eq: ['$zipCode', '" + SOME_VARIABLE_STRING_2 + "']}]}}}," +
                    "{ $project: { _id: 0, zipCode: 1, cutoffTime: 1 } }]," +
                    "as: 'deliveryZipCodeTimings'}}";

    TypedAggregation<FulfillmentChannel> aggregation = Aggregation.newAggregation(
            FulfillmentChannel.class,
            match,
            new CustomProjectAggregationOperation(query),
            match2
    );

    AggregationResults<FulfillmentChannel> results =
        mongoTemplate.aggregate(aggregation, FulfillmentChannel.class);
    return results.getMappedResults();
}

这篇关于使用管道聚合的 Spring Data MongoDB 查找的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！