Spring Data JPA @EnableJpaRepositories配置详解

@EnableJpaRepositories注解用于Srping JPA的代码配置，用于取代xml形式的配置文件，@EnableJpaRepositories支持的配置形式丰富多用，本篇文章详细讲解。

1、简单配置

@EnableJpaRepositories("com.spr.repository")

简单配置支持多个package，格式如下：

@EnableJpaRepositories({"com.cshtong.sample.repository", "com.cshtong.tower.repository"})

2、单值和多组值配置方式

大部分注解可以都支持单个注解方式和多个注解，多个注解通常采用"{}"符号包含的一组数据。

比如：字符串形式的  "x.y.z"  =>  {"x.y.z","a.b.c"}

类别： A.class => {A.class, B.class}

3、完整的@EnableJpaRepositories注解

@EnableJpaRepositories(
    basePackages = {},
    basePackageClasses = {},
    includeFilters = {},
    excludeFilters = {},
    repositoryImplementationPostfix = "Impl",
    namedQueriesLocation = "",//META-INF/jpa-named-queries.properties
    queryLookupStrategy=QueryLookupStrategy.Key.CREATE_IF_NOT_FOUND, //QueryLookupStrategy.Key.x
    repositoryFactoryBeanClass=JpaRepositoryFactoryBean.class, //class
    entityManagerFactoryRef="entityManagerFactory",
    transactionManagerRef="transactionManager",
    considerNestedRepositories=false, 
    enableDefaultTransactions=true
)

下面分别解释各个配置项的作用

1）basePackage

用于配置扫描Repositories所在的package及子package。简单配置中的配置则等同于此项配置值，basePackages可以配置为单个字符串，也可以配置为字符串数组形式。

@EnableJpaRepositories(
        basePackages = "com.cshtong")

多个包路径

@EnableJpaRepositories(
        basePackages = {"com.cshtong.sample.repository", "com.cshtong.tower.repository"})

2）basePackageClasses

指定 Repository 类

@EnableJpaRepositories(basePackageClasses = BookRepository.class)

@EnableJpaRepositories(
        basePackageClasses = {ShopRepository.class, OrganizationRepository.class})

备注：测试的时候发现，配置包类的一个Repositories类，该包内其他Repositores也会被加载

3）includeFilters

过滤器，该过滤区采用ComponentScan的过滤器类

@EnableJpaRepositories(
        includeFilters={@ComponentScan.Filter(type=FilterType.ANNOTATION, value=Repository.class)})

4）excludeFilters

不包含过滤器

@EnableJpaRepositories(
        excludeFilters={
                @ComponentScan.Filter(type=FilterType.ANNOTATION, value=Service.class),
                @ComponentScan.Filter(type=FilterType.ANNOTATION, value=Controller.class)})

5）repositoryImplementationPostfix

实现类追加的尾部，比如ShopRepository，对应的为ShopRepositoryImpl

6）namedQueriesLocation

named SQL存放的位置，默认为META-INF/jpa-named-queries.properties

7）queryLookupStrategy

构建条件查询的策略，包含三种方式CREATE，USE_DECLARED_QUERY，CREATE_IF_NOT_FOUND

• CREATE：按照接口名称自动构建查询
• USE_DECLARED_QUERY：用户声明查询
• CREATE_IF_NOT_FOUND：先搜索用户声明的，不存在则自动构建

该策略针对如下通过接口名称自动生成查询的场景

  List<Person> findByEmailAddressAndLastname(EmailAddress emailAddress, String lastname);

  // Enables the distinct flag for the query
  List<Person> findDistinctPeopleByLastnameOrFirstname(String lastname, String firstname);
  List<Person> findPeopleDistinctByLastnameOrFirstname(String lastname, String firstname);

  // Enabling ignoring case for an individual property
  List<Person> findByLastnameIgnoreCase(String lastname);
  // Enabling ignoring case for all suitable properties
  List<Person> findByLastnameAndFirstnameAllIgnoreCase(String lastname, String firstname);

  // Enabling static ORDER BY for a query
  List<Person> findByLastnameOrderByFirstnameAsc(String lastname);
  List<Person> findByLastnameOrderByFirstnameDesc(String lastname)

8）repositoryFactoryBeanClass

指定Repository的工厂类

9)entityManagerFactoryRef

实体管理工厂引用名称，对应到@Bean注解对应的方法

    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory() {
        LocalContainerEntityManagerFactoryBean entityManagerFactoryBean = new LocalContainerEntityManagerFactoryBean();
        entityManagerFactoryBean.setDataSource(dataSource());
        entityManagerFactoryBean.setPersistenceProviderClass(HibernatePersistenceProvider.class);
        entityManagerFactoryBean
                .setPackagesToScan(env.getRequiredProperty(PROPERTY_NAME_ENTITYMANAGER_PACKAGES_TO_SCAN));
        entityManagerFactoryBean.setJpaProperties(hibProperties());
        return entityManagerFactoryBean;
    }

10)transactionManagerRef

事务管理工厂引用名称，对应到@Bean注解对应的方法

	@Bean
	public JpaTransactionManager transactionManager() {
		JpaTransactionManager transactionManager = new JpaTransactionManager();
		transactionManager.setEntityManagerFactory(entityManagerFactory().getObject());
		return transactionManager;
	}