In mongodb spring data, how to achieve pagination for aggregation

Question

In mongodb spring data using mongotemplate or mongorepository how to achieve pagination for aggregation

Answer 1

In addition to the ssouris solution, you can use Pageable classes for results.

public Page<UserListItemView> list(final Pageable pageable) {

    final Aggregation agg = newAggregation(
        skip(pageable.getPageNumber() * pageable.getPageSize()),
        limit(pageable.getPageSize())
    );

    final List<UserListItemView> results = mongoTemplate
        .aggregate(agg, User.class, UserListItemView.class)
        .getMappedResults();

    return new PageImpl<>(results, pageable, results.size())
}

Answer 2

You can use MongoTemplate

org.spring.framework.data.mongodb.core.aggregation.Aggregation#skip
        and 
org.springframework.data.mongodb.core.aggregation.Aggregation#limit

Aggregation agg = newAggregation(
        project("tags"),
        skip(10),
        limit(10)
);

AggregationResults<TagCount> results = mongoTemplate.aggregate(agg, "tags", TagCount.class);
List<TagCount> tagCount = results.getMappedResults();

Answer 3

, , - , - .

Fırat KÜÇÜK, result.size(), "" PageImpl , , , . , , :

public Page<UserListItemView> list(final Pageable pageable) {
    long total = getCount(<your property name>, <your property value>);

    final Aggregation agg = newAggregation(
        skip(pageable.getPageNumber() * pageable.getPageSize()),
        limit(pageable.getPageSize())
    );

    final List<UserListItemView> results = mongoTemplate
        .aggregate(agg, User.class, UserListItemView.class)
        .getMappedResults();

    return new PageImpl<>(results, pageable, total);
}

, - , . , ( ), , ( , ), MatchOperation, GroupOperation,

private long getCount(String propertyName, String propertyValue) {
    MatchOperation matchOperation = match(Criteria.where(propertyName).is(propertyValue));
    GroupOperation groupOperation = group(propertyName).count().as("count");
    Aggregation aggregation = newAggregation(matchOperation, groupOperation);
    return mongoTemplate.aggregate(aggregation, Foo.class, NumberOfResults.class).getMappedResults().get(0).getCount();
}

private class NumberOfResults {
    private int count;

    public int getCount() {
        return count;
    }

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

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. , , - , :

private long getCount(String propertyName, String propertyValue) {
    Query countQuery = new Query(Criteria.where(propertyName).is(propertyValue));
    return mongoTemplate.count(countQuery, Foo.class);
}

Answer 4

fooobar.com/questions/181954/... Java.

, .

    AggregationOperation group = Aggregation.group().count().as("total")
            .addToSet(pageable.getPageNumber()).as("pageNumber")
            .addToSet(pageable.getPageSize()).as("pageSize")
            .addToSet(pageable.getOffset()).as("offset")
            .push("$$ROOT").as("data");

.

    AggregationOperation project = Aggregation.project()
            .andInclude("pageSize", "pageNumber", "total", "offset")
            .and(ArrayOperators.Slice.sliceArrayOf("data").offset((int) pageable.getOffset()).itemCount(pageable.getPageSize()))
            .as("data");

.

    Aggregation aggr = newAggregation(group, project);
    CustomPage page = mongoTemplate.aggregate(aggregation, Foo.class, CustomPage.class).getUniqueMappedResult();

.

    public class CustomPage {
        private long pageSize;
        private long pageNumber;
        private long offset;
        private long total;
        private List<Foo> data;
    }