时间戳

首页 > 解决方案 > 从 MongoDB 到 Spring Boot 聚合框架的聚合

mongodb - 从 MongoDB 到 Spring Boot 聚合框架的聚合

问题描述

我是 Spring 和 Mongo 的新手。我正在使用 Spring Batch 获取一些报告。我的查询需要一些MongoItemReader不支持的聚合，所以我按照下面的 stackoverflow 链接扩展了该类。

如何在春季批处理中将聚合查询与 MongoItemReader 一起使用

但是我的聚合有问题。我制作了在 mongoDB 中运行良好但无法将其转换为 Spring mongo 聚合的聚合。

MongoDb 聚合按预期工作。

db.getCollection('orders').aggregate([
  {$match: {orderDate: {$gt:"2021-03-15",$lt: "2021-03-17"}, "status" :{"$in": ["GREEN", "YELLOW"]}}},
  {$group: {_id: {orderDate: "$orderDate", node: "$node", code1:"$code1", code2:"$code2"}, orderUnts: {$sum: 1}}},
  {"$project": {orderDate:"$_id.orderDate", node:"$_id.node", code1:"$_id.code1", code2:"$_id.code2", orderUnts:"$orderUnts"}}
])

Spring Mongo 聚合导致错误。

String[] fields = {"orderDate", "node", "code1", "code2"};
String[] projectionFields = {"orderDate", "orderDate", "code1", "code2"};
MatchOperation matchOp = Aggregation.match(Criteria.where("orderDate").gt(startDate).and("orderDate").lt(endDate).and("status").in("GREEN", "YELLOW"));
GroupOperation groupOp = Aggregation.group(fields).sum("orderUnts").as("_id");
ProjectionOperation projectOp = Aggregation.project(projectionFields);
SortOperation sortOp = Aggregation.sort(Sort.by(Sort.Direction.ASC, "orderDate"));
Aggregation aggregation = Aggregation.newAggregation(matchOp, groupOp, projectOp, sortOp);

我正在低于唯一字段错误。

Caused by: java.lang.IllegalStateException: An implementation of MongoOperations is required.
at org.springframework.util.Assert.state(Assert.java:76)
at org.springframework.batch.item.data.MongoItemReader.afterPropertiesSet(MongoItemReader.java:238)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1847)
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1784)
... 81 common frames omitted

MongoItemReader 扩展类。

@Data
public class CustomMongoItemReader<T> extends MongoItemReader<T> {

    private MongoTemplate template;
    private Class<? extends T> type;
    private String collection;
    private MatchOperation matchOperation;
    private GroupOperation groupOperation;
    private ProjectionOperation projectionOperation;
    private SortOperation sortOperation;
    private Aggregation aggregation;

    @Override
    protected Iterator<T> doPageRead() {
        Pageable page = PageRequest.of(this.page, this.pageSize);
        if(matchOperation != null && groupOperation != null) {
            Aggregation agg = Aggregation.newAggregation(matchOperation,
                    groupOperation,
                    projectionOperation,
                    sortOperation,
                    Aggregation.skip(Long.valueOf(page.getPageNumber() * page.getPageSize())),
                    Aggregation.limit(page.getPageSize())
            );
            return (Iterator<T>) template.aggregate(agg, collection, this.type).iterator();
        }
        else {
            return Collections.emptyIterator();
        }
    }
}

如果问题需要更多信息，请告诉我。提前致谢。

标签： mongodbspring-bootaggregation-frameworkspring-batch

解决方案

还使用带有聚合所需属性的afterPropertiesSet()throws覆盖，用于 Reference check 。Exception{}MongoItemReader<T>

推荐阅读