com.mongodb.client.model

类 Aggregates

java.lang.Object

com.mongodb.client.model.Aggregates

public final class Aggregates
extends java.lang.Object

Builders for aggregation pipeline stages.

从以下版本开始:

3.1

MongoDB documentation

Aggregation pipeline

Since server release

2.2

方法概要

限定符和类型	方法和说明
static <TExpression> Bson	group(TExpression id, BsonField... fieldAccumulators) Creates a $group pipeline stage for the specified filter
static <TExpression> Bson	group(TExpression id, java.util.List<BsonField> fieldAccumulators) Creates a $group pipeline stage for the specified filter
static Bson	limit(int limit) Creates a $limit pipeline stage for the specified filter
static Bson	lookup(java.lang.String from, java.lang.String localField, java.lang.String foreignField, java.lang.String as) Creates a $lookup pipeline stage for the specified filter
static Bson	match(Bson filter) Creates a $match pipeline stage for the specified filter
static Bson	out(java.lang.String collectionName) Creates a $out pipeline stage for the specified filter
static Bson	project(Bson projection) Creates a $project pipeline stage for the specified projection
static Bson	sample(int size) Creates a $sample pipeline stage with the specified sample size
static Bson	skip(int skip) Creates a $skip pipeline stage
static Bson	sort(Bson sort) Creates a $sort pipeline stage for the specified sort specification
static Bson	unwind(java.lang.String fieldName) Creates a $unwind pipeline stage for the specified field name, which must be prefixed by a '$' sign.
static Bson	unwind(java.lang.String fieldName, UnwindOptions unwindOptions) Creates a $unwind pipeline stage for the specified field name, which must be prefixed by a '$' sign.

从类继承的方法 java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

方法详细资料

match

public static Bson match(Bson filter)

Creates a $match pipeline stage for the specified filter

参数:

filter - the filter to match

返回:

the $match pipeline stage

另请参阅:

Filters

MongoDB documentation

$match

project

public static Bson project(Bson projection)

Creates a $project pipeline stage for the specified projection

参数:

projection - the projection

返回:

the $project pipeline stage

另请参阅:

Projections

MongoDB documentation

$project

sort

public static Bson sort(Bson sort)

Creates a $sort pipeline stage for the specified sort specification

参数:

sort - the sort specification

返回:

the $sort pipeline stage

另请参阅:

Sorts

MongoDB documentation

$sort

skip

public static Bson skip(int skip)

Creates a $skip pipeline stage

参数:

skip - the number of documents to skip

返回:

the $skip pipeline stage

MongoDB documentation

$skip

limit

public static Bson limit(int limit)

Creates a $limit pipeline stage for the specified filter

参数:

limit - the limit

返回:

the $limit pipeline stage

MongoDB documentation

$limit

lookup

public static Bson lookup(java.lang.String from,
                          java.lang.String localField,
                          java.lang.String foreignField,
                          java.lang.String as)

Creates a $lookup pipeline stage for the specified filter

参数:

from - the name of the collection in the same database to perform the join with.

localField - specifies the field from the local collection to match values against.

foreignField - specifies the field in the from collection to match values against.

as - the name of the new array field to add to the input documents.

返回:

the $lookup pipeline stage

从以下版本开始:

3.2

MongoDB documentation

$lookup

Since server release

3.2

group

public static <TExpression> Bson group(TExpression id,
                                       BsonField... fieldAccumulators)

Creates a $group pipeline stage for the specified filter

类型参数:

TExpression - the expression type

参数:

id - the id expression for the group

fieldAccumulators - zero or more field accumulator pairs

返回:

the $group pipeline stage

MongoDB documentation

$group

Expressions

group

public static <TExpression> Bson group(TExpression id,
                                       java.util.List<BsonField> fieldAccumulators)

Creates a $group pipeline stage for the specified filter

类型参数:

TExpression - the expression type

参数:

id - the id expression for the group

fieldAccumulators - zero or more field accumulator pairs

返回:

the $group pipeline stage

MongoDB documentation

$group

Expressions

unwind

public static Bson unwind(java.lang.String fieldName)

Creates a $unwind pipeline stage for the specified field name, which must be prefixed by a '$' sign.

参数:

fieldName - the field name, prefixed by a '$' sign

返回:

the $unwind pipeline stage

MongoDB documentation

$unwind

unwind

public static Bson unwind(java.lang.String fieldName,
                          UnwindOptions unwindOptions)

Creates a $unwind pipeline stage for the specified field name, which must be prefixed by a '$' sign.

参数:

fieldName - the field name, prefixed by a '$' sign

unwindOptions - options for the unwind pipeline stage

返回:

the $unwind pipeline stage

从以下版本开始:

3.2

MongoDB documentation

$unwind

Since server release

3.2

out

public static Bson out(java.lang.String collectionName)

Creates a $out pipeline stage for the specified filter

参数:

collectionName - the collection name

返回:

the $out pipeline stage

MongoDB documentation

$out

Since server release

2.6

sample

public static Bson sample(int size)

Creates a $sample pipeline stage with the specified sample size

参数:

size - the sample size

返回:

the $sample pipeline stage

从以下版本开始:

3.2

MongoDB documentation

$sample

Since server release

3.2