MongoDB 聚合管道 - 计算符合复杂条件的记录数 -（找不到类型 java.lang.Object 的 PersistentEntity！）

Question

我有包含动态字段的文档，我需要为给定的复杂查询条件查找匹配记录的计数

示例实体

@Document(collection = "UserAttributes")
public class UserAttributesEntity {

    @Id
    @Getter
    private String id;

    @NotNull
    @Size(min = 1)
    @Getter @Setter
    private String userId;

    @NotNull
    @Getter @Setter
    private Map<String, Object> attributes = new HashMap<>();
}

示例数据：

{
    "_id" : ObjectId("6164542362affb14f3f2fef6"),
    "userId" : "89ee6942-289a-48c9-b0bb-210ea7c06a88",
    "attributes" : {
        "age" : 61,
        "name" : "Name1"
    }
},
{
    "_id" : ObjectId("6164548045cc4456792d5325"),
    "userId" : "538abb29-c09d-422e-97c1-df702dfb5930",
    "attributes" : {
        "age" : 40,
        "name" : "Name2",
        "location" : "IN"
    }
}

预期查询条件：

"((userAttributes.name == 'Name1' && userAttributes.age > 40) OR (userAttributes.location  == 'IN'))

使用 $match 构建如此复杂的标准会实施太多，因此我尝试通过 $project 使用 SPEL evolution，如下所示：

    private Mono<Long> aggregate() {
        final Aggregation aggregation = Aggregation
                .newAggregation(
                        Aggregation.project("userAttributes.playerLevel", "userAttributes.name")
                            .andExpression("((userAttributes.name == 'Name1' && userAttributes.age > 40) OR (userAttributes.location  == 'IN'))")
                            .as("result"),
                        Aggregation.match(Criteria.where("result").is(true)),
                        Aggregation.group().count().as("count"));

        return mongoTemplate.aggregate(aggregation, UserAttributesEntity.class, Map.class)
                .map(result -> Long.valueOf(result.get("count").toString()))
                .next();
    }

然而，上述逻辑因异常而失败：

org.springframework.data.mapping.MappingException: Couldn't find PersistentEntity for type java.lang.Object!
    at org.springframework.data.mapping.context.MappingContext.getRequiredPersistentEntity(MappingContext.java:119)
    at org.springframework.data.mapping.context.PersistentPropertyPathFactory.getPair(PersistentPropertyPathFactory.java:226)
    at org.springframework.data.mapping.context.PersistentPropertyPathFactory.createPersistentPropertyPath(PersistentPropertyPathFactory.java:199)
    at org.springframework.data.mapping.context.PersistentPropertyPathFactory.lambda$getPersistentPropertyPath(PersistentPropertyPathFactory.java:172)
    at java.base/java.util.concurrent.ConcurrentMap.computeIfAbsent(ConcurrentMap.java:330)
    at org.springframework.data.mapping.context.PersistentPropertyPathFactory.getPersistentPropertyPath(PersistentPropertyPathFactory.java:171)
    at org.springframework.data.mapping.context.PersistentPropertyPathFactory.from(PersistentPropertyPathFactory.java:71)
    at org.springframework.data.mapping.context.AbstractMappingContext.getPersistentPropertyPath(AbstractMappingContext.java:295)
    at org.springframework.data.mongodb.core.aggregation.TypeBasedAggregationOperationContext.getReferenceFor(TypeBasedAggregationOperationContext.java:163)
    at org.springframework.data.mongodb.core.aggregation.TypeBasedAggregationOperationContext.getReference(TypeBasedAggregationOperationContext.java:107)
    at org.springframework.data.mongodb.core.aggregation.AggregationExpressionTransformer$AggregationExpressionTransformationContext.getFieldReference(AggregationExpressionTransformer.java:82)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer$CompoundExpressionNodeConversion.convert(SpelExpressionTransformer.java:541)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.transform(SpelExpressionTransformer.java:113)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.transform(SpelExpressionTransformer.java:58)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer$ExpressionNodeConversion.transform(SpelExpressionTransformer.java:215)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer$ExpressionNodeConversion.transform(SpelExpressionTransformer.java:205)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer$OperatorNodeConversion.convert(SpelExpressionTransformer.java:257)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.transform(SpelExpressionTransformer.java:113)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.transform(SpelExpressionTransformer.java:58)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer$ExpressionNodeConversion.transform(SpelExpressionTransformer.java:215)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer$ExpressionNodeConversion.transform(SpelExpressionTransformer.java:205)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer$OperatorNodeConversion.convert(SpelExpressionTransformer.java:251)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.transform(SpelExpressionTransformer.java:113)
    at org.springframework.data.mongodb.core.aggregation.SpelExpressionTransformer.transform(SpelExpressionTransformer.java:105)
    at org.springframework.data.mongodb.core.aggregation.ProjectionOperation$ExpressionProjectionOperationBuilder$ExpressionProjection.toMongoExpression(ProjectionOperation.java:438)
    at org.springframework.data.mongodb.core.aggregation.ProjectionOperation$ExpressionProjectionOperationBuilder$ExpressionProjection.toDocument(ProjectionOperation.java:433)
    at org.springframework.data.mongodb.core.aggregation.ProjectionOperation.toDocument(ProjectionOperation.java:261)
    at org.springframework.data.mongodb.core.aggregation.AggregationOperation.toPipelineStages(AggregationOperation.java:55)
    at org.springframework.data.mongodb.core.aggregation.AggregationOperationRenderer.toDocument(AggregationOperationRenderer.java:56)
    at org.springframework.data.mongodb.core.aggregation.AggregationPipeline.toDocuments(AggregationPipeline.java:81)
    at org.springframework.data.mongodb.core.aggregation.Aggregation.toPipeline(Aggregation.java:705)
    at org.springframework.data.mongodb.core.AggregationUtil.createPipeline(AggregationUtil.java:105)
    at org.springframework.data.mongodb.core.ReactiveMongoTemplate.aggregate(ReactiveMongoTemplate.java:1001)
    at org.springframework.data.mongodb.core.ReactiveMongoTemplate.aggregate(ReactiveMongoTemplate.java:970)

我尝试进一步挖掘，它似乎在尝试将项目中使用的字段映射到适当的实体对象时失败了，在这种情况下，这里的投影字段实际上是 Map 对象并且无法识别匹配的实体（当然地图在 UserAttributesEntity 中）-除了上述方法之外，还有更好的方法来解决我的问题吗？

Answer 1

使用原始聚合解决了问题：

return mongoTemplate.aggregate(aggregation, mongoTemplate.getCollectionName(UserAttributesEntity.class), Map.class)
    .map(result -> Long.valueOf(result.get("count").toString()))
    .next()

MongoDB 聚合管道 - 计算符合复杂条件的记录数 -（找不到类型 java.lang.Object 的 PersistentEntity！）

MongoDB Aggregation Pipeline - Count no of records that are matching a complex criteria - (Couldn't find PersistentEntity for type java.lang.Object!)

java

mongodb

spring-data

aggregation-framework