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1. Preface

Spring Data JPA provides repository support for the Java Persistence API (JPA). It eases development of applications that need to access JPA data sources.

2. New & Noteworthy

2.1. What’s New in Spring Data JPA 1.11

Spring Data JPA 1.11 added the following features:

  • Improved compatibility with Hibernate 5.2.

  • Support any-match mode for [query-by-example].

  • Paged query optimizations.

  • Support for the exists projection in repository query derivation.

2.2. What’s New in Spring Data JPA 1.10

Spring Data JPA 1.10 added the following features:

  • Support for [projections] in repository query methods.

  • Support for [query-by-example].

  • The following annotations have been enabled to build on composed annotations: @EntityGraph, @Lock, @Modifying, @Query, @QueryHints, and @Procedure.

  • Support for the Contains keyword on collection expressions.

  • AttributeConverter implementations for ZoneId of JSR-310 and ThreeTenBP.

  • Upgrade to Querydsl 4, Hibernate 5, OpenJPA 2.4, and EclipseLink 2.6.1.

Unresolved directive in index.adoc - include::../../../../spring-data-commons/src/main/asciidoc/dependencies.adoc[leveloffset=+1]

Unresolved directive in index.adoc - include::../../../../spring-data-commons/src/main/asciidoc/repositories.adoc[leveloffset=+1]

3. Reference Documentation

4. JPA Repositories

This chapter points out the specialties for repository support for JPA. This builds on the core repository support explained in “[repositories]”. Make sure you have a sound understanding of the basic concepts explained there.

4.1. Introduction

This section describes the basics of configuring Spring Data JPA through either:

4.1.1. Spring Namespace

The JPA module of Spring Data contains a custom namespace that allows defining repository beans. It also contains certain features and element attributes that are special to JPA. Generally, the JPA repositories can be set up by using the repositories element, as shown in the following example:

Example 1. Setting up JPA repositories by using the namespace
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
  xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xmlns:jpa="http://www.springframework.org/schema/data/jpa"
  xsi:schemaLocation="http://www.springframework.org/schema/beans
    https://www.springframework.org/schema/beans/spring-beans.xsd
    http://www.springframework.org/schema/data/jpa
    https://www.springframework.org/schema/data/jpa/spring-jpa.xsd">

  <jpa:repositories base-package="com.acme.repositories" />

</beans>

Using the repositories element looks up Spring Data repositories as described in “[repositories.create-instances]”. Beyond that, it activates persistence exception translation for all beans annotated with @Repository, to let exceptions being thrown by the JPA persistence providers be converted into Spring’s DataAccessException hierarchy.

Custom Namespace Attributes

Beyond the default attributes of the repositories element, the JPA namespace offers additional attributes to let you gain more detailed control over the setup of the repositories:

Table 1. Custom JPA-specific attributes of the repositories element

entity-manager-factory-ref

Explicitly wire the EntityManagerFactory to be used with the repositories being detected by the repositories element. Usually used if multiple EntityManagerFactory beans are used within the application. If not configured, Spring Data automatically looks up the EntityManagerFactory bean with the name entityManagerFactory in the ApplicationContext.

transaction-manager-ref

Explicitly wire the PlatformTransactionManager to be used with the repositories being detected by the repositories element. Usually only necessary if multiple transaction managers or EntityManagerFactory beans have been configured. Default to a single defined PlatformTransactionManager inside the current ApplicationContext.

Spring Data JPA requires a PlatformTransactionManager bean named transactionManager to be present if no explicit transaction-manager-ref is defined.

4.1.2. Annotation-based Configuration

The Spring Data JPA repositories support can be activated not only through an XML namespace but also by using an annotation through JavaConfig, as shown in the following example:

Example 2. Spring Data JPA repositories using JavaConfig
@Configuration
@EnableJpaRepositories
@EnableTransactionManagement
class ApplicationConfig {

  @Bean
  public DataSource dataSource() {

    EmbeddedDatabaseBuilder builder = new EmbeddedDatabaseBuilder();
    return builder.setType(EmbeddedDatabaseType.HSQL).build();
  }

  @Bean
  public LocalContainerEntityManagerFactoryBean entityManagerFactory() {

    HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
    vendorAdapter.setGenerateDdl(true);

    LocalContainerEntityManagerFactoryBean factory = new LocalContainerEntityManagerFactoryBean();
    factory.setJpaVendorAdapter(vendorAdapter);
    factory.setPackagesToScan("com.acme.domain");
    factory.setDataSource(dataSource());
    return factory;
  }

  @Bean
  public PlatformTransactionManager transactionManager(EntityManagerFactory entityManagerFactory) {

    JpaTransactionManager txManager = new JpaTransactionManager();
    txManager.setEntityManagerFactory(entityManagerFactory);
    return txManager;
  }
}
You must create LocalContainerEntityManagerFactoryBean and not EntityManagerFactory directly, since the former also participates in exception translation mechanisms in addition to creating EntityManagerFactory.

The preceding configuration class sets up an embedded HSQL database by using the EmbeddedDatabaseBuilder API of spring-jdbc. Spring Data then sets up an EntityManagerFactory and uses Hibernate as the sample persistence provider. The last infrastructure component declared here is the JpaTransactionManager. Finally, the example activates Spring Data JPA repositories by using the @EnableJpaRepositories annotation, which essentially carries the same attributes as the XML namespace. If no base package is configured, it uses the one in which the configuration class resides.

4.1.3. Bootstrap Mode

By default, Spring Data JPA repositories are default Spring beans. They are singleton scoped and eagerly initialized. During startup, they already interact with the JPA EntityManager for verification and metadata analysis purposes. Spring Framework supports the initialization of the JPA EntityManagerFactory in a background thread because that process usually takes up a significant amount of startup time in a Spring application. To make use of that background initialization effectively, we need to make sure that JPA repositories are initialized as late as possible.

As of Spring Data JPA 2.1 you can now configure a BootstrapMode (either via the @EnableJpaRepositories annotation or the XML namespace) that takes the following values:

  • DEFAULT (default) — Repositories are instantiated eagerly unless explicitly annotated with @Lazy. The lazification only has effect if no client bean needs an instance of the repository as that will require the initialization of the repository bean.

  • LAZY — Implicitly declares all repository beans lazy and also causes lazy initialization proxies to be created to be injected into client beans. That means, that repositories will not get instantiated if the client bean is simply storing the instance in a field and not making use of the repository during initialization. Repository instances will be initialized and verified upon first interaction with the repository.

  • DEFERRED — Fundamentally the same mode of operation as LAZY, but triggering repository initialization in response to an ContextRefreshedEvent so that repositories are verified before the application has completely started.

Recommendations

If you’re not using asynchronous JPA bootstrap stick with the default bootstrap mode.

In case you bootstrap JPA asynchronously, DEFERRED is a reasonable default as it will make sure the Spring Data JPA bootstrap only waits for the EntityManagerFactory setup if that itself takes longer than initializing all other application components. Still, it makes sure that repositories are properly initialized and validated before the application signals it’s up.

LAZY is a decent choice for testing scenarios and local development. Once you are pretty sure that repositories can properly bootstrap, or in cases where you are testing other parts of the application, running verification for all repositories might unnecessarily increase the startup time. The same applies to local development in which you only access parts of the application that might need to have a single repository initialized.

4.2. Persisting Entities

This section describes how to persist (save) entities with Spring Data JPA.

4.2.1. Saving Entities

Saving an entity can be performed with the CrudRepository.save(…) method. It persists or merges the given entity by using the underlying JPA EntityManager. If the entity has not yet been persisted, Spring Data JPA saves the entity with a call to the entityManager.persist(…) method. Otherwise, it calls the entityManager.merge(…) method.

Entity State-detection Strategies

Spring Data JPA offers the following strategies to detect whether an entity is new or not:

  1. Version-Property and Id-Property inspection (default): By default Spring Data JPA inspects first if there is a Version-property of non-primitive type. If there is, the entity is considered new if the value of that property is null. Without such a Version-property Spring Data JPA inspects the identifier property of the given entity. If the identifier property is null, then the entity is assumed to be new. Otherwise, it is assumed to be not new.

  2. Implementing Persistable: If an entity implements Persistable, Spring Data JPA delegates the new detection to the isNew(…) method of the entity. See the JavaDoc for details.

  3. Implementing EntityInformation: You can customize the EntityInformation abstraction used in the SimpleJpaRepository implementation by creating a subclass of JpaRepositoryFactory and overriding the getEntityInformation(…) method accordingly. You then have to register the custom implementation of JpaRepositoryFactory as a Spring bean. Note that this should be rarely necessary. See the JavaDoc for details.

Option 1 is not an option for entities that use manually assigned identifiers as with those the identifier will always be non-null. A common pattern in that scenario is to use a common base class with a transient flag defaulting to indicate a new instance and using JPA lifecycle callbacks to flip that flag on persistence operations:

Example 3. A base class for entities with manually assigned identifiers
@MappedSuperclass
public abstract class AbstractEntity<ID> implements Persistable<ID> {

  @Transient
  private boolean isNew = true; (1)

  @Override
  public boolean isNew() {
    return isNew; (2)
  }

  @PrePersist (3)
  @PostLoad
  void markNotNew() {
    this.isNew = false;
  }

  // More code…
}
1 Declare a flag to hold the new state. Transient so that it’s not persisted to the database.
2 Return the flag in the implementation of Persistable.isNew() so that Spring Data repositories know whether to call EntityManager.persist() or ….merge().
3 Declare a method using JPA entity callbacks so that the flag is switched to indicate an existing entity after a repository call to save(…) or an instance creation by the persistence provider.

4.3. Query Methods

This section describes the various ways to create a query with Spring Data JPA.

4.3.1. Query Lookup Strategies

The JPA module supports defining a query manually as a String or having it being derived from the method name.

Derived queries with the predicates IsStartingWith, StartingWith, StartsWith, IsEndingWith, EndingWith, EndsWith, IsNotContaining, NotContaining, NotContains, IsContaining, Containing, Contains the respective arguments for these queries will get sanitized. This means if the arguments actually contain characters recognized by LIKE as wildcards these will get escaped so they match only as literals. The escape character used can be configured by setting the escapeCharacter of the @EnableJpaRepositories annotation. Compare with Using SpEL Expressions.

Declared Queries

Although getting a query derived from the method name is quite convenient, one might face the situation in which either the method name parser does not support the keyword one wants to use or the method name would get unnecessarily ugly. So you can either use JPA named queries through a naming convention (see Using JPA Named Queries for more information) or rather annotate your query method with @Query (see Using @Query for details).

4.3.2. Query Creation

Generally, the query creation mechanism for JPA works as described in “[repositories.query-methods]”. The following example shows what a JPA query method translates into:

Example 4. Query creation from method names
public interface UserRepository extends Repository<User, Long> {

  List<User> findByEmailAddressAndLastname(String emailAddress, String lastname);
}

We create a query using the JPA criteria API from this, but, essentially, this translates into the following query: select u from User u where u.emailAddress = ?1 and u.lastname = ?2. Spring Data JPA does a property check and traverses nested properties, as described in “[repositories.query-methods.query-property-expressions]”.

The following table describes the keywords supported for JPA and what a method containing that keyword translates to:

Table 2. Supported keywords inside method names
Keyword Sample JPQL snippet

Distinct

findDistinctByLastnameAndFirstname

select distinct …​ where x.lastname = ?1 and x.firstname = ?2

And

findByLastnameAndFirstname

… where x.lastname = ?1 and x.firstname = ?2

Or

findByLastnameOrFirstname

… where x.lastname = ?1 or x.firstname = ?2

Is, Equals

findByFirstname,findByFirstnameIs,findByFirstnameEquals

… where x.firstname = ?1

Between

findByStartDateBetween

… where x.startDate between ?1 and ?2

LessThan

findByAgeLessThan

… where x.age < ?1

LessThanEqual

findByAgeLessThanEqual

… where x.age <= ?1

GreaterThan

findByAgeGreaterThan

… where x.age > ?1

GreaterThanEqual

findByAgeGreaterThanEqual

… where x.age >= ?1

After

findByStartDateAfter

… where x.startDate > ?1

Before

findByStartDateBefore

… where x.startDate < ?1

IsNull, Null

findByAge(Is)Null

… where x.age is null

IsNotNull, NotNull

findByAge(Is)NotNull

… where x.age not null

Like

findByFirstnameLike

… where x.firstname like ?1

NotLike

findByFirstnameNotLike

… where x.firstname not like ?1

StartingWith

findByFirstnameStartingWith

… where x.firstname like ?1 (parameter bound with appended %)

EndingWith

findByFirstnameEndingWith

… where x.firstname like ?1 (parameter bound with prepended %)

Containing

findByFirstnameContaining

… where x.firstname like ?1 (parameter bound wrapped in %)

OrderBy

findByAgeOrderByLastnameDesc

… where x.age = ?1 order by x.lastname desc

Not

findByLastnameNot

… where x.lastname <> ?1

In

findByAgeIn(Collection<Age> ages)

… where x.age in ?1

NotIn

findByAgeNotIn(Collection<Age> ages)

… where x.age not in ?1

True

findByActiveTrue()

… where x.active = true

False

findByActiveFalse()

… where x.active = false

IgnoreCase

findByFirstnameIgnoreCase

… where UPPER(x.firstname) = UPPER(?1)

In and NotIn also take any subclass of Collection as a parameter as well as arrays or varargs. For other syntactical versions of the same logical operator, check “[repository-query-keywords]”.

4.3.3. Using JPA Named Queries

The examples use the <named-query /> element and @NamedQuery annotation. The queries for these configuration elements have to be defined in the JPA query language. Of course, you can use <named-native-query /> or @NamedNativeQuery too. These elements let you define the query in native SQL by losing the database platform independence.
XML Named Query Definition

To use XML configuration, add the necessary <named-query /> element to the orm.xml JPA configuration file located in the META-INF folder of your classpath. Automatic invocation of named queries is enabled by using some defined naming convention. For more details, see below.

Example 5. XML named query configuration
<named-query name="User.findByLastname">
  <query>select u from User u where u.lastname = ?1</query>
</named-query>

The query has a special name that is used to resolve it at runtime.

Annotation-based Configuration

Annotation-based configuration has the advantage of not needing another configuration file to be edited, lowering maintenance effort. You pay for that benefit by the need to recompile your domain class for every new query declaration.

Example 6. Annotation-based named query configuration
@Entity
@NamedQuery(name = "User.findByEmailAddress",
  query = "select u from User u where u.emailAddress = ?1")
public class User {

}
Declaring Interfaces

To allow these named queries, specify the UserRepository as follows:

Example 7. Query method declaration in UserRepository
public interface UserRepository extends JpaRepository<User, Long> {

  List<User> findByLastname(String lastname);

  User findByEmailAddress(String emailAddress);
}

Spring Data tries to resolve a call to these methods to a named query, starting with the simple name of the configured domain class, followed by the method name separated by a dot. So the preceding example would use the named queries defined earlier instead of trying to create a query from the method name.

4.3.4. Using @Query

Using named queries to declare queries for entities is a valid approach and works fine for a small number of queries. As the queries themselves are tied to the Java method that runs them, you can actually bind them directly by using the Spring Data JPA @Query annotation rather than annotating them to the domain class. This frees the domain class from persistence specific information and co-locates the query to the repository interface.

Queries annotated to the query method take precedence over queries defined using @NamedQuery or named queries declared in orm.xml.

The following example shows a query created with the @Query annotation:

Example 8. Declare query at the query method using @Query
public interface UserRepository extends JpaRepository<User, Long> {

  @Query("select u from User u where u.emailAddress = ?1")
  User findByEmailAddress(String emailAddress);
}
Using Advanced LIKE Expressions

The query running mechanism for manually defined queries created with @Query allows the definition of advanced LIKE expressions inside the query definition, as shown in the following example:

Example 9. Advanced like expressions in @Query
public interface UserRepository extends JpaRepository<User, Long> {

  @Query("select u from User u where u.firstname like %?1")
  List<User> findByFirstnameEndsWith(String firstname);
}

In the preceding example, the LIKE delimiter character (%) is recognized, and the query is transformed into a valid JPQL query (removing the %). Upon running the query, the parameter passed to the method call gets augmented with the previously recognized LIKE pattern.

Native Queries

The @Query annotation allows for running native queries by setting the nativeQuery flag to true, as shown in the following example:

Example 10. Declare a native query at the query method using @Query
public interface UserRepository extends JpaRepository<User, Long> {

  @Query(value = "SELECT * FROM USERS WHERE EMAIL_ADDRESS = ?1", nativeQuery = true)
  User findByEmailAddress(String emailAddress);
}
Spring Data JPA does not currently support dynamic sorting for native queries, because it would have to manipulate the actual query declared, which it cannot do reliably for native SQL. You can, however, use native queries for pagination by specifying the count query yourself, as shown in the following example:
Example 11. Declare native count queries for pagination at the query method by using @Query
public interface UserRepository extends JpaRepository<User, Long> {

  @Query(value = "SELECT * FROM USERS WHERE LASTNAME = ?1",
    countQuery = "SELECT count(*) FROM USERS WHERE LASTNAME = ?1",
    nativeQuery = true)
  Page<User> findByLastname(String lastname, Pageable pageable);
}

A similar approach also works with named native queries, by adding the .count suffix to a copy of your query. You probably need to register a result set mapping for your count query, though.

4.3.5. Using Sort

Sorting can be done by either providing a PageRequest or by using Sort directly. The properties actually used within the Order instances of Sort need to match your domain model, which means they need to resolve to either a property or an alias used within the query. The JPQL defines this as a state field path expression.

Using any non-referenceable path expression leads to an Exception.

However, using Sort together with @Query lets you sneak in non-path-checked Order instances containing functions within the ORDER BY clause. This is possible because the Order is appended to the given query string. By default, Spring Data JPA rejects any Order instance containing function calls, but you can use JpaSort.unsafe to add potentially unsafe ordering.

The following example uses Sort and JpaSort, including an unsafe option on JpaSort:

Example 12. Using Sort and JpaSort
public interface UserRepository extends JpaRepository<User, Long> {

  @Query("select u from User u where u.lastname like ?1%")
  List<User> findByAndSort(String lastname, Sort sort);

  @Query("select u.id, LENGTH(u.firstname) as fn_len from User u where u.lastname like ?1%")
  List<Object[]> findByAsArrayAndSort(String lastname, Sort sort);
}

repo.findByAndSort("lannister", Sort.by("firstname"));                (1)
repo.findByAndSort("stark", Sort.by("LENGTH(firstname)"));            (2)
repo.findByAndSort("targaryen", JpaSort.unsafe("LENGTH(firstname)")); (3)
repo.findByAsArrayAndSort("bolton", Sort.by("fn_len"));               (4)
1 Valid Sort expression pointing to property in domain model.
2 Invalid Sort containing function call. Throws Exception.
3 Valid Sort containing explicitly unsafe Order.
4 Valid Sort expression pointing to aliased function.

4.3.6. Using Named Parameters

By default, Spring Data JPA uses position-based parameter binding, as described in all the preceding examples. This makes query methods a little error-prone when refactoring regarding the parameter position. To solve this issue, you can use @Param annotation to give a method parameter a concrete name and bind the name in the query, as shown in the following example:

Example 13. Using named parameters
public interface UserRepository extends JpaRepository<User, Long> {

  @Query("select u from User u where u.firstname = :firstname or u.lastname = :lastname")
  User findByLastnameOrFirstname(@Param("lastname") String lastname,
                                 @Param("firstname") String firstname);
}
The method parameters are switched according to their order in the defined query.
As of version 4, Spring fully supports Java 8’s parameter name discovery based on the -parameters compiler flag. By using this flag in your build as an alternative to debug information, you can omit the @Param annotation for named parameters.

4.3.7. Using SpEL Expressions

As of Spring Data JPA release 1.4, we support the usage of restricted SpEL template expressions in manually defined queries that are defined with @Query. Upon the query being run, these expressions are evaluated against a predefined set of variables. Spring Data JPA supports a variable called entityName. Its usage is select x from #{#entityName} x. It inserts the entityName of the domain type associated with the given repository. The entityName is resolved as follows: If the domain type has set the name property on the @Entity annotation, it is used. Otherwise, the simple class-name of the domain type is used.

The following example demonstrates one use case for the #{#entityName} expression in a query string where you want to define a repository interface with a query method and a manually defined query:

Example 14. Using SpEL expressions in repository query methods - entityName
@Entity
public class User {

  @Id
  @GeneratedValue
  Long id;

  String lastname;
}

public interface UserRepository extends JpaRepository<User,Long> {

  @Query("select u from #{#entityName} u where u.lastname = ?1")
  List<User> findByLastname(String lastname);
}

To avoid stating the actual entity name in the query string of a @Query annotation, you can use the #{#entityName} variable.

The entityName can be customized by using the @Entity annotation. Customizations in orm.xml are not supported for the SpEL expressions.

Of course, you could have just used User in the query declaration directly, but that would require you to change the query as well. The reference to #entityName picks up potential future remappings of the User class to a different entity name (for example, by using @Entity(name = "MyUser").

Another use case for the #{#entityName} expression in a query string is if you want to define a generic repository interface with specialized repository interfaces for a concrete domain type. To not repeat the definition of custom query methods on the concrete interfaces, you can use the entity name expression in the query string of the @Query annotation in the generic repository interface, as shown in the following example:

Example 15. Using SpEL expressions in repository query methods - entityName with inheritance
@MappedSuperclass
public abstract class AbstractMappedType {
  …
  String attribute
}

@Entity
public class ConcreteType extends AbstractMappedType { … }

@NoRepositoryBean
public interface MappedTypeRepository<T extends AbstractMappedType>
  extends Repository<T, Long> {

  @Query("select t from #{#entityName} t where t.attribute = ?1")
  List<T> findAllByAttribute(String attribute);
}

public interface ConcreteRepository
  extends MappedTypeRepository<ConcreteType> { … }

In the preceding example, the MappedTypeRepository interface is the common parent interface for a few domain types extending AbstractMappedType. It also defines the generic findAllByAttribute(…) method, which can be used on instances of the specialized repository interfaces. If you now invoke findByAllAttribute(…) on ConcreteRepository, the query becomes select t from ConcreteType t where t.attribute = ?1.

SpEL expressions to manipulate arguments may also be used to manipulate method arguments. In these SpEL expressions the entity name is not available, but the arguments are. They can be accessed by name or index as demonstrated in the following example.

Example 16. Using SpEL expressions in repository query methods - accessing arguments.
@Query("select u from User u where u.firstname = ?1 and u.firstname=?#{[0]} and u.emailAddress = ?#{principal.emailAddress}")
List<User> findByFirstnameAndCurrentUserWithCustomQuery(String firstname);

For like-conditions one often wants to append % to the beginning or the end of a String valued parameter. This can be done by appending or prefixing a bind parameter marker or a SpEL expression with %. Again the following example demonstrates this.

Example 17. Using SpEL expressions in repository query methods - wildcard shortcut.
@Query("select u from User u where u.lastname like %:#{[0]}% and u.lastname like %:lastname%")
List<User> findByLastnameWithSpelExpression(@Param("lastname") String lastname);

When using like-conditions with values that are coming from a not secure source the values should be sanitized so they can’t contain any wildcards and thereby allow attackers to select more data than they should be able to. For this purpose the escape(String) method is made available in the SpEL context. It prefixes all instances of _ and % in the first argument with the single character from the second argument. In combination with the escape clause of the like expression available in JPQL and standard SQL this allows easy cleaning of bind parameters.

Example 18. Using SpEL expressions in repository query methods - sanitizing input values.
@Query("select u from User u where u.firstname like %?#{escape([0])}% escape ?#{escapeCharacter()}")
List<User> findContainingEscaped(String namePart);

Given this method declaration in a repository interface findContainingEscaped("Peter_") will find Peter_Parker but not Peter Parker. The escape character used can be configured by setting the escapeCharacter of the @EnableJpaRepositories annotation. Note that the method escape(String) available in the SpEL context will only escape the SQL and JPQL standard wildcards _ and %. If the underlying database or the JPA implementation supports additional wildcards these will not get escaped.

4.3.8. Modifying Queries

All the previous sections describe how to declare queries to access a given entity or collection of entities. You can add custom modifying behavior by using the custom method facilities described in “[repositories.custom-implementations]”. As this approach is feasible for comprehensive custom functionality, you can modify queries that only need parameter binding by annotating the query method with @Modifying, as shown in the following example:

Example 19. Declaring manipulating queries
@Modifying
@Query("update User u set u.firstname = ?1 where u.lastname = ?2")
int setFixedFirstnameFor(String firstname, String lastname);

Doing so triggers the query annotated to the method as an updating query instead of a selecting one. As the EntityManager might contain outdated entities after the execution of the modifying query, we do not automatically clear it (see the JavaDoc of EntityManager.clear() for details), since this effectively drops all non-flushed changes still pending in the EntityManager. If you wish the EntityManager to be cleared automatically, you can set the @Modifying annotation’s clearAutomatically attribute to true.

The @Modifying annotation is only relevant in combination with the @Query annotation. Derived query methods or custom methods do not require this annotation.

Derived Delete Queries

Spring Data JPA also supports derived delete queries that let you avoid having to declare the JPQL query explicitly, as shown in the following example:

Example 20. Using a derived delete query
interface UserRepository extends Repository<User, Long> {

  void deleteByRoleId(long roleId);

  @Modifying
  @Query("delete from User u where u.role.id = ?1")
  void deleteInBulkByRoleId(long roleId);
}

Although the deleteByRoleId(…) method looks like it basically produces the same result as the deleteInBulkByRoleId(…), there is an important difference between the two method declarations in terms of the way they are run. As the name suggests, the latter method issues a single JPQL query (the one defined in the annotation) against the database. This means even currently loaded instances of User do not see lifecycle callbacks invoked.

To make sure lifecycle queries are actually invoked, an invocation of deleteByRoleId(…) runs a query and then deletes the returned instances one by one, so that the persistence provider can actually invoke @PreRemove callbacks on those entities.

In fact, a derived delete query is a shortcut for running the query and then calling CrudRepository.delete(Iterable<User> users) on the result and keeping behavior in sync with the implementations of other delete(…) methods in CrudRepository.

4.3.9. Applying Query Hints

To apply JPA query hints to the queries declared in your repository interface, you can use the @QueryHints annotation. It takes an array of JPA @QueryHint annotations plus a boolean flag to potentially disable the hints applied to the additional count query triggered when applying pagination, as shown in the following example:

Example 21. Using QueryHints with a repository method
public interface UserRepository extends Repository<User, Long> {

  @QueryHints(value = { @QueryHint(name = "name", value = "value")},
              forCounting = false)
  Page<User> findByLastname(String lastname, Pageable pageable);
}

The preceding declaration would apply the configured @QueryHint for that actually query but omit applying it to the count query triggered to calculate the total number of pages.

4.3.10. Configuring Fetch- and LoadGraphs

The JPA 2.1 specification introduced support for specifying Fetch- and LoadGraphs that we also support with the @EntityGraph annotation, which lets you reference a @NamedEntityGraph definition. You can use that annotation on an entity to configure the fetch plan of the resulting query. The type (Fetch or Load) of the fetching can be configured by using the type attribute on the @EntityGraph annotation. See the JPA 2.1 Spec 3.7.4 for further reference.

The following example shows how to define a named entity graph on an entity:

Example 22. Defining a named entity graph on an entity.
@Entity
@NamedEntityGraph(name = "GroupInfo.detail",
  attributeNodes = @NamedAttributeNode("members"))
public class GroupInfo {

  // default fetch mode is lazy.
  @ManyToMany
  List<GroupMember> members = new ArrayList<GroupMember>();

  …
}

The following example shows how to reference a named entity graph on a repository query method:

Example 23. Referencing a named entity graph definition on a repository query method.
@Repository
public interface GroupRepository extends CrudRepository<GroupInfo, String> {

  @EntityGraph(value = "GroupInfo.detail", type = EntityGraphType.LOAD)
  GroupInfo getByGroupName(String name);

}

It is also possible to define ad hoc entity graphs by using @EntityGraph. The provided attributePaths are translated into the according EntityGraph without needing to explicitly add @NamedEntityGraph to your domain types, as shown in the following example:

Example 24. Using AD-HOC entity graph definition on an repository query method.
@Repository
public interface GroupRepository extends CrudRepository<GroupInfo, String> {

  @EntityGraph(attributePaths = { "members" })
  GroupInfo getByGroupName(String name);

}

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4.4. Stored Procedures

The JPA 2.1 specification introduced support for calling stored procedures by using the JPA criteria query API. We Introduced the @Procedure annotation for declaring stored procedure metadata on a repository method.

The examples to follow use the following stored procedure:

Example 25. The definition of the plus1inout procedure in HSQL DB.
/;
DROP procedure IF EXISTS plus1inout
/;
CREATE procedure plus1inout (IN arg int, OUT res int)
BEGIN ATOMIC
 set res = arg + 1;
END
/;

Metadata for stored procedures can be configured by using the NamedStoredProcedureQuery annotation on an entity type.

Example 26. StoredProcedure metadata definitions on an entity.
@Entity
@NamedStoredProcedureQuery(name = "User.plus1", procedureName = "plus1inout", parameters = {
  @StoredProcedureParameter(mode = ParameterMode.IN, name = "arg", type = Integer.class),
  @StoredProcedureParameter(mode = ParameterMode.OUT, name = "res", type = Integer.class) })
public class User {}

Note that @NamedStoredProcedureQuery has two different names for the stored procedure. name is the name JPA uses. procedureName is the name the stored procedure has in the database.

You can reference stored procedures from a repository method in multiple ways. The stored procedure to be called can either be defined directly by using the value or procedureName attribute of the @Procedure annotation. This refers directly to the stored procedure in the database and ignores any configuration via @NamedStoredProcedureQuery.

Alternatively you may specify the @NamedStoredProcedureQuery.name attribute as the @Procedure.name attribute. If neither value, procedureName nor name is configured, the name of the repository method is used as the name attribute.

The following example shows how to reference an explicitly mapped procedure:

Example 27. Referencing explicitly mapped procedure with name "plus1inout" in database.
@Procedure("plus1inout")
Integer explicitlyNamedPlus1inout(Integer arg);

The following example is equivalent to the previous one but uses the procedureName alias:

Example 28. Referencing implicitly mapped procedure with name "plus1inout" in database via procedureName alias.
@Procedure(procedureName = "plus1inout")
Integer callPlus1InOut(Integer arg);

The following is again equivalent to the previous two but using the method name instead of an explicite annotation attribute.

Example 29. Referencing implicitly mapped named stored procedure "User.plus1" in EntityManager by using the method name.
@Procedure
Integer plus1inout(@Param("arg") Integer arg);

The following example shows how to reference a stored procedure by referencing the @NamedStoredProcedureQuery.name attribute.

Example 30. Referencing explicitly mapped named stored procedure "User.plus1IO" in EntityManager.
@Procedure(name = "User.plus1IO")
Integer entityAnnotatedCustomNamedProcedurePlus1IO(@Param("arg") Integer arg);

If the stored procedure getting called has a single out parameter that parameter may be returned as the return value of the method. If there are multiple out parameters specified in a @NamedStoredProcedureQuery annotation those can be returned as a Map with the key being the parameter name given in the @NamedStoredProcedureQuery annotation.

4.5. Specifications

JPA 2 introduces a criteria API that you can use to build queries programmatically. By writing a criteria, you define the where clause of a query for a domain class. Taking another step back, these criteria can be regarded as a predicate over the entity that is described by the JPA criteria API constraints.

Spring Data JPA takes the concept of a specification from Eric Evans' book, “Domain Driven Design”, following the same semantics and providing an API to define such specifications with the JPA criteria API. To support specifications, you can extend your repository interface with the JpaSpecificationExecutor interface, as follows:

public interface CustomerRepository extends CrudRepository<Customer, Long>, JpaSpecificationExecutor {
 …
}

The additional interface has methods that let you run specifications in a variety of ways. For example, the findAll method returns all entities that match the specification, as shown in the following example:

List<T> findAll(Specification<T> spec);

The Specification interface is defined as follows:

public interface Specification<T> {
  Predicate toPredicate(Root<T> root, CriteriaQuery<?> query,
            CriteriaBuilder builder);
}

Specifications can easily be used to build an extensible set of predicates on top of an entity that then can be combined and used with JpaRepository without the need to declare a query (method) for every needed combination, as shown in the following example:

Example 31. Specifications for a Customer
public class CustomerSpecs {


  public static Specification<Customer> isLongTermCustomer() {
    return (root, query, builder) -> {
      LocalDate date = LocalDate.now().minusYears(2);
      return builder.lessThan(root.get(Customer_.createdAt), date);
    };
  }

  public static Specification<Customer> hasSalesOfMoreThan(MonetaryAmount value) {
    return (root, query, builder) -> {
      // build query here
    };
  }
}

The Customer_ type is a metamodel type generated using the JPA Metamodel generator (see the Hibernate implementation’s documentation for an example). So the expression, Customer_.createdAt, assumes the Customer has a createdAt attribute of type Date. Besides that, we have expressed some criteria on a business requirement abstraction level and created executable Specifications. So a client might use a Specification as follows:

Example 32. Using a simple Specification
List<Customer> customers = customerRepository.findAll(isLongTermCustomer());

Why not create a query for this kind of data access? Using a single Specification does not gain a lot of benefit over a plain query declaration. The power of specifications really shines when you combine them to create new Specification objects. You can achieve this through the default methods of Specification we provide to build expressions similar to the following:

Example 33. Combined Specifications
MonetaryAmount amount = new MonetaryAmount(200.0, Currencies.DOLLAR);
List<Customer> customers = customerRepository.findAll(
  isLongTermCustomer().or(hasSalesOfMoreThan(amount)));

Specification offers some “glue-code” default methods to chain and combine Specification instances. These methods let you extend your data access layer by creating new Specification implementations and combining them with already existing implementations.

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4.6. Running an Example

In Spring Data JPA, you can use Query by Example with Repositories, as shown in the following example:

Example 34. Query by Example using a Repository
public interface PersonRepository extends JpaRepository<Person, String> { … }

public class PersonService {

  @Autowired PersonRepository personRepository;

  public List<Person> findPeople(Person probe) {
    return personRepository.findAll(Example.of(probe));
  }
}
Currently, only SingularAttribute properties can be used for property matching.

The property specifier accepts property names (such as firstname and lastname). You can navigate by chaining properties together with dots (address.city). You can also tune it with matching options and case sensitivity.

The following table shows the various StringMatcher options that you can use and the result of using them on a field named firstname:

Table 3. StringMatcher options
Matching Logical result

DEFAULT (case-sensitive)

firstname = ?0

DEFAULT (case-insensitive)

LOWER(firstname) = LOWER(?0)

EXACT (case-sensitive)

firstname = ?0

EXACT (case-insensitive)

LOWER(firstname) = LOWER(?0)

STARTING (case-sensitive)

firstname like ?0 + '%'

STARTING (case-insensitive)

LOWER(firstname) like LOWER(?0) + '%'

ENDING (case-sensitive)

firstname like '%' + ?0

ENDING (case-insensitive)

LOWER(firstname) like '%' + LOWER(?0)

CONTAINING (case-sensitive)

firstname like '%' + ?0 + '%'

CONTAINING (case-insensitive)

LOWER(firstname) like '%' + LOWER(?0) + '%'

4.7. Transactionality

By default, CRUD methods on repository instances are transactional. For read operations, the transaction configuration readOnly flag is set to true. All others are configured with a plain @Transactional so that default transaction configuration applies. For details, see JavaDoc of SimpleJpaRepository. If you need to tweak transaction configuration for one of the methods declared in a repository, redeclare the method in your repository interface, as follows:

Example 35. Custom transaction configuration for CRUD
public interface UserRepository extends CrudRepository<User, Long> {

  @Override
  @Transactional(timeout = 10)
  public List<User> findAll();

  // Further query method declarations
}

Doing so causes the findAll() method to run with a timeout of 10 seconds and without the readOnly flag.

Another way to alter transactional behaviour is to use a facade or service implementation that (typically) covers more than one repository. Its purpose is to define transactional boundaries for non-CRUD operations. The following example shows how to use such a facade for more than one repository:

Example 36. Using a facade to define transactions for multiple repository calls
@Service
class UserManagementImpl implements UserManagement {

  private final UserRepository userRepository;
  private final RoleRepository roleRepository;

  @Autowired
  public UserManagementImpl(UserRepository userRepository,
    RoleRepository roleRepository) {
    this.userRepository = userRepository;
    this.roleRepository = roleRepository;
  }

  @Transactional
  public void addRoleToAllUsers(String roleName) {

    Role role = roleRepository.findByName(roleName);

    for (User user : userRepository.findAll()) {
      user.addRole(role);
      userRepository.save(user);
    }
}

This example causes call to addRoleToAllUsers(…) to run inside a transaction (participating in an existing one or creating a new one if none are already running). The transaction configuration at the repositories is then neglected, as the outer transaction configuration determines the actual one used. Note that you must activate <tx:annotation-driven /> or use @EnableTransactionManagement explicitly to get annotation-based configuration of facades to work. This example assumes you use component scanning.

Note that the call to save is not strictly necessary from a JPA point of view, but should still be there in order to stay consistent to the repository abstraction offered by Spring Data.

4.7.1. Transactional query methods

To let your query methods be transactional, use @Transactional at the repository interface you define, as shown in the following example:

Example 37. Using @Transactional at query methods
@Transactional(readOnly = true)
public interface UserRepository extends JpaRepository<User, Long> {

  List<User> findByLastname(String lastname);

  @Modifying
  @Transactional
  @Query("delete from User u where u.active = false")
  void deleteInactiveUsers();
}

Typically, you want the readOnly flag to be set to true, as most of the query methods only read data. In contrast to that, deleteInactiveUsers() makes use of the @Modifying annotation and overrides the transaction configuration. Thus, the method runs with the readOnly flag set to false.

You can use transactions for read-only queries and mark them as such by setting the readOnly flag. Doing so does not, however, act as a check that you do not trigger a manipulating query (although some databases reject INSERT and UPDATE statements inside a read-only transaction). The readOnly flag is instead propagated as a hint to the underlying JDBC driver for performance optimizations. Furthermore, Spring performs some optimizations on the underlying JPA provider. For example, when used with Hibernate, the flush mode is set to NEVER when you configure a transaction as readOnly, which causes Hibernate to skip dirty checks (a noticeable improvement on large object trees).

4.8. Locking

To specify the lock mode to be used, you can use the @Lock annotation on query methods, as shown in the following example:

Example 38. Defining lock metadata on query methods
interface UserRepository extends Repository<User, Long> {

  // Plain query method
  @Lock(LockModeType.READ)
  List<User> findByLastname(String lastname);
}

This method declaration causes the query being triggered to be equipped with a LockModeType of READ. You can also define locking for CRUD methods by redeclaring them in your repository interface and adding the @Lock annotation, as shown in the following example:

Example 39. Defining lock metadata on CRUD methods
interface UserRepository extends Repository<User, Long> {

  // Redeclaration of a CRUD method
  @Lock(LockModeType.READ)
  List<User> findAll();
}

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4.8.1. JPA Auditing

General Auditing Configuration

Spring Data JPA ships with an entity listener that can be used to trigger the capturing of auditing information. First, you must register the AuditingEntityListener to be used for all entities in your persistence contexts inside your orm.xml file, as shown in the following example:

Example 40. Auditing configuration orm.xml
<persistence-unit-metadata>
  <persistence-unit-defaults>
    <entity-listeners>
      <entity-listener class="….data.jpa.domain.support.AuditingEntityListener" />
    </entity-listeners>
  </persistence-unit-defaults>
</persistence-unit-metadata>

You can also enable the AuditingEntityListener on a per-entity basis by using the @EntityListeners annotation, as follows:

@Entity
@EntityListeners(AuditingEntityListener.class)
public class MyEntity {

}
The auditing feature requires spring-aspects.jar to be on the classpath.

With orm.xml suitably modified and spring-aspects.jar on the classpath, activating auditing functionality is a matter of adding the Spring Data JPA auditing namespace element to your configuration, as follows:

Example 41. Activating auditing using XML configuration
<jpa:auditing auditor-aware-ref="yourAuditorAwareBean" />

As of Spring Data JPA 1.5, you can enable auditing by annotating a configuration class with the @EnableJpaAuditing annotation. You must still modify the orm.xml file and have spring-aspects.jar on the classpath. The following example shows how to use the @EnableJpaAuditing annotation:

Example 42. Activating auditing with Java configuration
@Configuration
@EnableJpaAuditing
class Config {

  @Bean
  public AuditorAware<AuditableUser> auditorProvider() {
    return new AuditorAwareImpl();
  }
}

If you expose a bean of type AuditorAware to the ApplicationContext, the auditing infrastructure automatically picks it up and uses it to determine the current user to be set on domain types. If you have multiple implementations registered in the ApplicationContext, you can select the one to be used by explicitly setting the auditorAwareRef attribute of @EnableJpaAuditing.

4.9. Miscellaneous Considerations

4.9.1. Using JpaContext in Custom Implementations

When working with multiple EntityManager instances and custom repository implementations, you need to wire the correct EntityManager into the repository implementation class. You can do so by explicitly naming the EntityManager in the @PersistenceContext annotation or, if the EntityManager is @Autowired, by using @Qualifier.

As of Spring Data JPA 1.9, Spring Data JPA includes a class called JpaContext that lets you obtain the EntityManager by managed domain class, assuming it is managed by only one of the EntityManager instances in the application. The following example shows how to use JpaContext in a custom repository:

Example 43. Using JpaContext in a custom repository implementation
class UserRepositoryImpl implements UserRepositoryCustom {

  private final EntityManager em;

  @Autowired
  public UserRepositoryImpl(JpaContext context) {
    this.em = context.getEntityManagerByManagedType(User.class);
  }

  …
}

The advantage of this approach is that, if the domain type gets assigned to a different persistence unit, the repository does not have to be touched to alter the reference to the persistence unit.

4.9.2. Merging persistence units

Spring supports having multiple persistence units. Sometimes, however, you might want to modularize your application but still make sure that all these modules run inside a single persistence unit. To enable that behavior, Spring Data JPA offers a PersistenceUnitManager implementation that automatically merges persistence units based on their name, as shown in the following example:

Example 44. Using MergingPersistenceUnitmanager
<bean class="….LocalContainerEntityManagerFactoryBean">
  <property name="persistenceUnitManager">
    <bean class="….MergingPersistenceUnitManager" />
  </property>
</bean>
Classpath Scanning for @Entity Classes and JPA Mapping Files

A plain JPA setup requires all annotation-mapped entity classes to be listed in orm.xml. The same applies to XML mapping files. Spring Data JPA provides a ClasspathScanningPersistenceUnitPostProcessor that gets a base package configured and optionally takes a mapping filename pattern. It then scans the given package for classes annotated with @Entity or @MappedSuperclass, loads the configuration files that match the filename pattern, and hands them to the JPA configuration. The post-processor must be configured as follows:

Example 45. Using ClasspathScanningPersistenceUnitPostProcessor
<bean class="….LocalContainerEntityManagerFactoryBean">
  <property name="persistenceUnitPostProcessors">
    <list>
      <bean class="org.springframework.data.jpa.support.ClasspathScanningPersistenceUnitPostProcessor">
        <constructor-arg value="com.acme.domain" />
        <property name="mappingFileNamePattern" value="**/*Mapping.xml" />
      </bean>
    </list>
  </property>
</bean>
As of Spring 3.1, a package to scan can be configured on the LocalContainerEntityManagerFactoryBean directly to enable classpath scanning for entity classes. See the JavaDoc for details.

4.9.3. CDI Integration

Instances of the repository interfaces are usually created by a container, for which Spring is the most natural choice when working with Spring Data. Spring offers sophisticated support for creating bean instances, as documented in [repositories.create-instances]. As of version 1.1.0, Spring Data JPA ships with a custom CDI extension that allows using the repository abstraction in CDI environments. The extension is part of the JAR. To activate it, include the Spring Data JPA JAR on your classpath.

You can now set up the infrastructure by implementing a CDI Producer for the EntityManagerFactory and EntityManager, as shown in the following example:

class EntityManagerFactoryProducer {

  @Produces
  @ApplicationScoped
  public EntityManagerFactory createEntityManagerFactory() {
    return Persistence.createEntityManagerFactory("my-persistence-unit");
  }

  public void close(@Disposes EntityManagerFactory entityManagerFactory) {
    entityManagerFactory.close();
  }

  @Produces
  @RequestScoped
  public EntityManager createEntityManager(EntityManagerFactory entityManagerFactory) {
    return entityManagerFactory.createEntityManager();
  }

  public void close(@Disposes EntityManager entityManager) {
    entityManager.close();
  }
}

The necessary setup can vary depending on the JavaEE environment. You may need to do nothing more than redeclare a EntityManager as a CDI bean, as follows:

class CdiConfig {

  @Produces
  @RequestScoped
  @PersistenceContext
  public EntityManager entityManager;
}

In the preceding example, the container has to be capable of creating JPA EntityManagers itself. All the configuration does is re-export the JPA EntityManager as a CDI bean.

The Spring Data JPA CDI extension picks up all available EntityManager instances as CDI beans and creates a proxy for a Spring Data repository whenever a bean of a repository type is requested by the container. Thus, obtaining an instance of a Spring Data repository is a matter of declaring an @Injected property, as shown in the following example:

class RepositoryClient {

  @Inject
  PersonRepository repository;

  public void businessMethod() {
    List<Person> people = repository.findAll();
  }
}

5. Appendix

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Appendix A: Frequently Asked Questions

Common

  1. I’d like to get more detailed logging information on what methods are called inside JpaRepository for example. How can I gain them?

    You can make use of CustomizableTraceInterceptor provided by Spring, as shown in the following example:

    <bean id="customizableTraceInterceptor" class="
      org.springframework.aop.interceptor.CustomizableTraceInterceptor">
      <property name="enterMessage" value="Entering $[methodName]($[arguments])"/>
      <property name="exitMessage" value="Leaving $[methodName](): $[returnValue]"/>
    </bean>
    
    <aop:config>
      <aop:advisor advice-ref="customizableTraceInterceptor"
        pointcut="execution(public * org.springframework.data.jpa.repository.JpaRepository+.*(..))"/>
    </aop:config>

Infrastructure

  1. Currently I have implemented a repository layer based on HibernateDaoSupport. I create a SessionFactory by using Spring’s AnnotationSessionFactoryBean. How do I get Spring Data repositories working in this environment?

    You have to replace AnnotationSessionFactoryBean with the HibernateJpaSessionFactoryBean, as follows:

    Example 46. Looking up a SessionFactory from a HibernateEntityManagerFactory
    <bean id="sessionFactory" class="org.springframework.orm.jpa.vendor.HibernateJpaSessionFactoryBean">
      <property name="entityManagerFactory" ref="entityManagerFactory"/>
    </bean>

Auditing

  1. I want to use Spring Data JPA auditing capabilities but have my database already configured to set modification and creation date on entities. How can I prevent Spring Data from setting the date programmatically?

    Set the set-dates attribute of the auditing namespace element to false.

Appendix B: Glossary

AOP

Aspect oriented programming

Commons DBCP

Commons DataBase Connection Pools - a library from the Apache foundation that offers pooling implementations of the DataSource interface.

CRUD

Create, Read, Update, Delete - Basic persistence operations.

DAO

Data Access Object - Pattern to separate persisting logic from the object to be persisted

Dependency Injection

Pattern to hand a component’s dependency to the component from outside, freeing the component to lookup the dependent itself. For more information, see https://en.wikipedia.org/wiki/Dependency_Injection.

EclipseLink

Object relational mapper implementing JPA - https://www.eclipse.org/eclipselink/

Hibernate

Object relational mapper implementing JPA - https://hibernate.org/

JPA

Java Persistence API

Spring

Java application framework - https://projects.spring.io/spring-framework