Spring Data MongoDB七：进阶Aggregation操作（下）

╰半夏微凉° 2024-02-17 18:23 22阅读 0赞

本文转载至：[http://blog.csdn.net/congcong68/article/details/52821362][http_blog.csdn.net_congcong68_article_details_52821362]

## 一、Spring Data MongoDB Aggregation 简介  ##

上一篇已经Aggregation 做了很详细的介绍，这边就不在介绍，[spring][] Data MongoDB 项目提供与MongoDB文档[数据库][Link 1]的集成，Spring Data MongoDB提供org.springframework.data.mongodb.core.MongoTemplate是对Connection进行封装，提供了连接管理，Spring Data MongoDB 像[hibernate][spring]等一样提供了模板，mongoTemplate提供调用Aggregation 方法。

## 二、Spring Data MongoDB Aggregation 方法  ##

mongoTemplate提供调用4个Aggregation 方法

![Center][]

**【AggregationOperation】**

MongoDB Aggregation 提供了Aggregation Operations ，Spring Data MongoDB 也提供这些方法，方便的操作

Pipeline Aggregation Operators project, skip, limit, unwind, group, sort, geoNear

Group Aggregation Operators addToSet, first, last, max, min, avg, push, sum, (\*count)

Arithmetic Aggregation Operators add (\*via plus), subtract (\*via minus), multiply, divide, mod

Comparison Aggregation Operators eq (\*via: is), gt, gte, lt, lte, ne

**Group Aggregation查看源代码：**

GroupOperation implements FieldsExposingAggregationOperation ， FieldsExposingAggregationOperation extends AggregationOperation

GroupOperation 提供了 addToSet, first, last, max, min, avg, push, sum等方法

![Center 1][]

**【TypedAggregation】**

TypedAggregation<I> extends Aggregation 提供了Class<I> inputType 一个输入类型，也就是对哪个集合进行操作，我们可以查看源代码

![Center 2][]

**【outputType】**

输出类型，可以指定具体的实体类型，官方的例子：

更多的例子可以查看官方网文档 [Spring Data MongoDB 文档][Spring Data MongoDB]

![Center 3][]

outputType我们项目中运用比较多的是BasicDBObject.class，操作也比较方便，不用特意定义一个实体类，可以把Aggregation封装一个通用的方法。

## 三、Spring Data MongoDB Aggregation 例子  ##

我们需要查询订单号为001,002,003中的订单详情各个产品卖出多少个，并且过滤掉数量小于1的产品

**【Aggregation 实现类】**

**\[java\]** [view plain][] [copy][view plain]

[![在CODE上查看代码片][CODE]][CODE_CODE] [![派生到我的代码片][ico_fork.svg]][ico_fork.svg 1]

1.  @Override
2.  **public****void** getAggregation() \{ 
3.   Set<String> onumberSet=**new** HashSet<String>(); 
4.   onumberSet.add("001"); 
5.   onumberSet.add("002"); 
6.   onumberSet.add("003"); 
7.   Aggregation agg = Aggregation.newAggregation( 
8.   Aggregation.match(Criteria.where("onumber").in(onumberSet)), 
9.   Aggregation.unwind("items"), 
10.  Aggregation.group("items.ino").sum("items.quantity").as("total"), 
11.  Aggregation.match(Criteria.where("total").gt(1)) 
12.  ); 
13. 
14.  AggregationResults<BasicDBObject> outputType=mongoTemplate.aggregate(agg,"orders", BasicDBObject.**class**); 
15. **for** (Iterator<BasicDBObject> iterator = outputType.iterator(); iterator.hasNext();) \{ 
16.  DBObject obj =iterator.next(); 
17.  System.out.println(obj.toString()); 
18.  \} 
19.

**【测试类】**

**\[java\]** [view plain][] [copy][view plain]

[![在CODE上查看代码片][CODE]][CODE_CODE] [![派生到我的代码片][ico_fork.svg]][ico_fork.svg 1]

1.  **public****class** TestOrders \{ 
2.  **private****static** OrdersDao ordersDaoImpl; 
3.  **private****static** ClassPathXmlApplicationContext app; 
4.  @BeforeClass
5.  **public****static****void** initSpring() \{ 
6.  **try** \{ 
7.   app = **new** ClassPathXmlApplicationContext("classpath:applicationContext-mongo.xml"); 
8.   ordersDaoImpl = (OrdersDao) app.getBean("ordersDaoImpl"); 
9.   \} **catch** (Exception e) \{ 
10.  e.printStackTrace(); 
11.  \} 
12.  \} 
13. 
14. @Test
15. **public****void** testAggregation() 
16.  \{ 
17.  ordersDaoImpl.getAggregation(); 
18. 
19.  \} 
20. \}

【测试结果】

![Center 4][]

[http_blog.csdn.net_congcong68_article_details_52821362]: http://blog.csdn.net/congcong68/article/details/52821362
[spring]: http://lib.csdn.net/base/javaee
[Link 1]: http://lib.csdn.net/base/mysql
[Center]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/d131f2e8d05645de89ab82cd173be006.png
[Center 1]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/fc2bfd25980741d6969f729a8cabb8f3.png
[Center 2]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/d6119364c2494ac580080f4e974feb21.png
[Spring Data MongoDB]: http://docs.spring.io/spring-data/data-mongo/docs/1.7.0.RC1/reference/html/#mongodb-connectors
[Center 3]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/93a435f157684b77a2e87eccef49da78.png
[view plain]: http://blog.csdn.net/congcong68/article/details/52821362#
[CODE]: https://code.csdn.net/assets/CODE_ico.png
[CODE_CODE]: https://code.csdn.net/snippets/1930042
[ico_fork.svg]: https://code.csdn.net/assets/ico_fork.svg
[ico_fork.svg 1]: https://code.csdn.net/snippets/1930042/fork
[Center 4]: https://image.dandelioncloud.cn/pgy_files/images/2024/01/29/9b3a8f49626d4994aa47786388f10ef9.png