Spring Data 学习笔记

怼烎@ 2021-09-29 05:40 383阅读 0赞

# Spring Data #

## 1.Spring Data JPA ##

JPA是一个规范，用于操作各种数据库。

## 2.Spring Data Mongodb ##

Spring Data对Mongodb的支持。

### 2.1 方法映射 ###

支持方法映射，根据方法规则生成SQL进行查询，方法命名规则参见4；

Flux<StudentEntity> findByNameAndSex(String name, String sex);

### 2.2 聚合操作支持 ###

Spring Data MongoDB支持在2.2版中引入MongoDB的聚合框架。

在Spring数据MongoDB中的聚合框架的支持是基于以下关键抽象：Aggregation，AggregationOperation，和AggregationResults。

*  1 Aggregation

> 表示MongoDB aggregate操作，并保存聚合管道指令的描述。  
> 通过调用类的相应newAggregation(…)静态工厂方法来创建聚合Aggregation，  
> 该方法采用列表AggregateOperation和可选的输入类。  
> 实际的聚合操作由the的aggregate方法执行，该方法MongoTemplate将所需的输出类作为参数。

*  2 AggregationOperation

> 表示MongoDB聚合管道操作，并描述了应在此聚合步骤中执行的处理。  
> 虽然您可以手动创建AggregationOperation，但我们建议使用Aggregate类提供的静态工厂方法来构造AggregateOperation。

*  3 AggregationResults

> 聚合操作结果的容器。它提供对原始聚合结果的访问，Document以映射对象的形式和有关聚合的其他信息。

使用Spring Data MongoDB对MongoDB聚合框架的示例：

import static org.springframework.data.mongodb.core.aggregation.Aggregation.*;
    
    Aggregation agg = newAggregation(
        pipelineOP1(),
        pipelineOP2(),
        pipelineOPn()
    );
    
    AggregationResults<OutputType> results = mongoTemplate.aggregate(agg, "INPUT_COLLECTION_NAME", OutputType.class);
    List<OutputType> mappedResult = results.getMappedResults();

Spring Data MongoDB当前支持的聚合操作

TypedAggregation<Student> aggregation = Aggregation.newAggregation(Student.class, match(new Criteria()
                    .andOperator(Criteria.where("orga").is(org)
                            .and("enable").is(true)
                            .and("user").is(userId)
                            .and("resour").is(eventId)
                            .and("").is("Access"))));
            return mongoTemplate.aggregate(aggregation, "students", Student.class);

这两个是一样的：

public Flux<Student> findRoleByNameAndPermissions(List<String> names) { 
    
        Query query = query(where("科目").is("语文").and("name").in(names));
    
        Flux<RoleEntity> roles = mongoTemplate.find(query, Student.class, "students");
        return roles;
    }
    
    public Flux<Student> findCatalogs1(List<String> roleNames) { 
        TypedAggregation<Student> aggregation = Aggregation.newAggregation(Student.class,
                match(new Criteria().andOperator(Criteria.where("name").in("names").and("科目").is("语文"))));
        return mongoTemplate.aggregate(aggregation, "students", Student.class);
    
    
    }

//or查询
    Query query = query(where("name").is(name)
                    .and("age").is(age)
                    .orOperator(where("teacher").is("校长"),
                            where("mother").is("teacher")));
            return mongoTemplate.find(query, Student.class, "students");

## 3.Spring Data Redis ##

Spring Data对Redis的支持。

## 4.Spring Data 方法名中支持的关键字 ##

<table> 
 <thead> 
  <tr> 
   <th>关键词</th> 
   <th>示范</th> 
   <th>等同于</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>And</td> 
   <td>findByLastnameAndFirstname</td> 
   <td>… where x.lastname = ?1 and x.firstname = ?2</td> 
  </tr> 
  <tr> 
   <td>Or</td> 
   <td>findByLastnameOrFirstname</td> 
   <td>… where x.lastname = ?1 or x.firstname = ?2</td> 
  </tr> 
  <tr> 
   <td>Is,Equals</td> 
   <td>findByFirstname,findByFirstnameIs,findByFirstnameEquals</td> 
   <td>… where x.firstname = ?1</td> 
  </tr> 
  <tr> 
   <td>Between</td> 
   <td>findByStartDateBetween</td> 
   <td>… where x.startDate between ?1 and ?2</td> 
  </tr> 
  <tr> 
   <td>LessThan</td> 
   <td>findByAgeLessThan</td> 
   <td>… where x.age &lt; ?1</td> 
  </tr> 
  <tr> 
   <td>LessThanEqual</td> 
   <td>findByAgeLessThanEqual</td> 
   <td>… where x.age &lt;= ?1</td> 
  </tr> 
  <tr> 
   <td>GreaterThan</td> 
   <td>findByAgeGreaterThan</td> 
   <td>… where x.age &gt; ?1</td> 
  </tr> 
  <tr> 
   <td>GreaterThanEqual</td> 
   <td>findByAgeGreaterThanEqual</td> 
   <td>… where x.age &gt;= ?1</td> 
  </tr> 
  <tr> 
   <td>After</td> 
   <td>findByStartDateAfter</td> 
   <td>… where x.startDate &gt; ?1</td> 
  </tr> 
  <tr> 
   <td>Before</td> 
   <td>findByStartDateBefore</td> 
   <td>… where x.startDate &lt; ?1</td> 
  </tr> 
  <tr> 
   <td>IsNull</td> 
   <td>findByAgeIsNull</td> 
   <td>… where x.age is null</td> 
  </tr> 
  <tr> 
   <td>IsNotNull,NotNull</td> 
   <td>findByAge(Is)NotNull</td> 
   <td>… where x.age not null</td> 
  </tr> 
  <tr> 
   <td>Like</td> 
   <td>findByFirstnameLike</td> 
   <td>… where x.firstname like ?1</td> 
  </tr> 
  <tr> 
   <td>NotLike</td> 
   <td>findByFirstnameNotLike</td> 
   <td>… where x.firstname not like ?1</td> 
  </tr> 
  <tr> 
   <td>StartingWith</td> 
   <td>findByFirstnameStartingWith</td> 
   <td>… where x.firstname like ?1（附加参数绑定%）</td> 
  </tr> 
  <tr> 
   <td>EndingWith</td> 
   <td>findByFirstnameEndingWith</td> 
   <td>… where x.firstname like ?1（与前置绑定的参数%）</td> 
  </tr> 
  <tr> 
   <td>Containing</td> 
   <td>findByFirstnameContaining</td> 
   <td>… where x.firstname like ?1（包含参数绑定%）</td> 
  </tr> 
  <tr> 
   <td>OrderBy</td> 
   <td>findByAgeOrderByLastnameDesc</td> 
   <td>… where x.age = ?1 order by x.lastname desc</td> 
  </tr> 
  <tr> 
   <td>Not</td> 
   <td>findByLastnameNot</td> 
   <td>… where x.lastname &lt;&gt; ?1</td> 
  </tr> 
  <tr> 
   <td>In</td> 
   <td>findByAgeIn(Collection ages)</td> 
   <td>… where x.age in ?1</td> 
  </tr> 
  <tr> 
   <td>NotIn</td> 
   <td>findByAgeNotIn(Collection ages)</td> 
   <td>… where x.age not in ?1</td> 
  </tr> 
  <tr> 
   <td>True</td> 
   <td>findByActiveTrue()</td> 
   <td>… where x.active = true</td> 
  </tr> 
  <tr> 
   <td>False</td> 
   <td>findByActiveFalse()</td> 
   <td>… where x.active = false</td> 
  </tr> 
  <tr> 
   <td>IgnoreCase</td> 
   <td>findByFirstnameIgnoreCase</td> 
   <td>… where UPPER(x.firstame) = UPPER(?1)</td> 
  </tr> 
 </tbody> 
</table>

[https://docs.spring.io/spring-data/mongodb/docs/2.1.9.RELEASE/reference/html/\#mongo.aggregation.supported-aggregation-operations][https_docs.spring.io_spring-data_mongodb_docs_2.1.9.RELEASE_reference_html_mongo.aggregation.supported-aggregation-operations]

[https_docs.spring.io_spring-data_mongodb_docs_2.1.9.RELEASE_reference_html_mongo.aggregation.supported-aggregation-operations]: https://docs.spring.io/spring-data/mongodb/docs/2.1.9.RELEASE/reference/html/#mongo.aggregation.supported-aggregation-operations