# spring-data-jpa-extra ## use spring data jpa more comfortable I love spring-data-jpa, she set my hands free, crud methods are boring! However she is not perfect on dynamic native query and her return type must be an entity, although she provide us a specification solution, but i think it's heavy and not easy to use.

spring-data-jpa-extra comes to solve three problem:

• dynamic native query support like mybatis
• return type can be anything
• no code, just sql

Example

• first add ComponentScan

by java bean

@ComponentScan({"com.slyak","your.base.package"})

by xml

<context:component-scan base-package="com.slyak,your.base.package"/>

• second extends GenericJpaRepository insteadof JpaRepository

	public interface SampleRepository extends GenericJpaRepository<Sample, Long> {
		@TemplateQuery
		Page<Sample> findByContent(String content, Pageable pageable);
		@TemplateQuery
		CustomVO findCustomVO(Long id);
	}

• third create a file named Sample.sftl in your classpath:/sqls/ (you can change this path by setting placeholder spring.jpa.template-location)

• In version 2.0.0.RELEASE , new template 'sftl' take place of xml (xml is complex, but it is also supported). sftl is a ftl template mixed with sqls. The template will be simplified as below. It can be recognized in Intellij IDEA , follow thease steps: settings->Editor->File Types , find "Freemarker Template" and register a new type named '*.sftl',choose it's 'Template Data Language' such as 'MYSQL'.

--findByContent
SELECT * FROM t_sample WHERE 1=1
<#if content??>
AND content LIKE :content
</#if>

--findCustomVO
SELECT id,name as viewName FROM t_sample WHERE id=:id

How to use?

you can use it by using source code or adding a maven dependency

    <dependency>
        <groupId>com.slyak</groupId>
        <artifactId>spring-data-jpa-extra</artifactId>
        <version>2.0.0.RELEASE</version>
    </dependency>

config with annotation

@EnableJpaRepositories(basePackages = "your.packages", repositoryBaseClass = GenericJpaRepositoryImpl.class, repositoryFactoryBeanClass = GenericJpaRepositoryFactoryBean.class)

or with xml

<jpa:repositories base-package="your.packages" repository-base-class="com.slyak.spring.jpa.GenericJpaRepositoryImpl" repository-factory-bean-class="com.slyak.spring.jpa.GenericJpaRepositoryFactoryBean"/>

2 Miniute Tutorial

Template Query

Methods annotated with @TemplateQuery tells QueryLookupStrategy to look up query by content,this is often used by dynamic query.

Template Query Object

Object annotated with @TemplateQueryObject tells content process engine render params provided by object properties.

Entity Assemblers

Entity assemblers can assembler entity with other entities, such as one to many relation or one to one relation.

More Useful Methods (eg: mget togglestatus fakedelete)

    //batch get items and put the result into a map
    Map<ID, T> mget(Collection<ID> ids);
    
    //get items one by one for cache
    Map<ID, T> mgetOneByOne(Collection<ID> ids);
    
    //get items one by one for cache
    List<T> findAllOneByOne(Collection<ID> ids);
    
    //toggle entity status if it has a Status property
    void toggleStatus(ID id);
    
    //set entity status to Status.DELETED if it has a Status property
    void fakeDelete(ID... id);

TODO List

• More types of content support (now freemarker)
• More JPA comparison support (now hibernate)
• Performance test and do some optimization
• More other useful features
• Change to the latest spring-data-jpa version

Change Log

CHANGELOG

How to use in old version ( <2.0 )

old version guide