java - 如何在 mongo morphia 中对 2 个日期求和？

Question

我有一个问题，我想在吗啡中编写这样的代码

select sum(amount) from y where date > a and date < b

在 Robo3T 中我已经成功创建查询

db.TransactionLog.aggregate([
  { 
    $match: {
      transactionTimestamp: {
        $gte: ISODate("2018-06-05T07:10:22.725Z"),
        $lt: ISODate("2019-07-01T07:10:22.725Z")
      },
        senderAccount:"1234567890"
    }
  }, {
    $group: {
      _id: null,
      total: {
        $sum: "$amount"
      }
    }
  }
]);

结果

{
    "_id" : null,
    "total" : NumberDecimal("55987000.00")
}

但是如何用java代码编写呢？我已经尝试过这样了

Query<TransactionLog> query = datastore.createQuery(TransactionLog.class);
    AggregationPipeline pipeline = datastore.createAggregation(TransactionLog.class)
            .match(
                    query
                            .filter("transactionTimestamp >=", new Date(2018, 6, 5, 0, 0, 0))
                            .filter("transactionTimestamp <=", new Date(2019, 7, 15, 0, 0, 0))
                            .filter("senderAccount", "0012101781")
            ).group(Group.grouping("count", new Accumulator("$sum", "amount")))
            ;
    AggregationOptions opts = AggregationOptions.builder().outputMode(OutputMode.CURSOR).build();
    pipeline.aggregate(TransactionLog.class, opts);
    Iterator<BigDecimal> result = pipeline.out(BigDecimal.class);

但我收到这样的错误

Command failed with error 9: 'The 'cursor' option is required, except for aggregate with the explain argument' on server XXXXX:27017. The full response is { "ok" : 0.0, "errmsg" : "The 'cursor' option is required, except for aggregate with the explain argument", "code" : 9, "codeName" : "FailedToParse" }

谢谢

Answer 1

答案在这里

首先制作pojo

public class Summary {

    private BigDecimal count;

    public BigDecimal getCount() {
        return count;
    }

    public void setCount(BigDecimal count) {
        this.count = count;
    }
}

第二个是代码

Query<TransactionLog> query = datastore.createQuery(TransactionLog.class);


            query.field("transactionTimestamp").greaterThanOrEq(oneYearAgo());
            query.field("transactionTimestamp").lessThanOrEq(new Date());
            query.field("senderAccount").equal("1234567890");


            Iterator<Summary> pipeline = datastore.createAggregation(TransactionLog.class)
                    .match(query)
                    .group(Group.grouping("count", new Accumulator("$sum", "amount")))
                    .aggregate(Summary.class, AggregationOptions.builder()
                            .outputMode(AggregationOptions.OutputMode.CURSOR)
                            .build());

            while (pipeline.hasNext()) {
                Summary x = pipeline.next();
                System.out.println(x.getCount());
            }

祝你有美好的一天!