Spring Data Repositories - Best Practices

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Spring Data RepositoriesBest PracticesOliver Gierke & Thomas Darimont

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Oliver Gierke

Spring Data EngineerProject lead Core/JPA/MongoDB

ogierke@gopivotal.comwww.olivergierke.deolivergierke

Wednesday, September 11, 13

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Thomas Darimont

Spring Data Engineer

tdarimont@gopivotal.com

thomasdarimontwww.tutorials.de

Core/JPA/MongoDB

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Spring DataModern Data Access For Enterprise Java

NoSQLJPA

JDBC

Redis

Big Data Hadoop

HBase

MongoDB Neo4j REST exporter

Roo

HivePig

Querydsl Repositories

1 free copy per attendee!

Gemfire

Splunk

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#184

By: Oliver Gierke

ABOUT THE SPRING DATA PROJECT

The Spring Data project is part of the ecosystem surrounding the Spring Framework and constitutes an umbrella project for advanced data access related topics. It contains modules to support traditional relational data stores (based on plain JDBC or JPA), NoSQL ones (like MongoDB, Neo4j or Redis), and big data technologies like Apache Hadoop. The core mission of the project is to provide a familiar and consistent Spring-based programming model for various data access technologies while retaining VWRUH�VSHFLͤF�IHDWXUHV�DQG�FDSDELOLWLHV�

General Themes,QIUDVWUXFWXUH�&RQͤJXUDWLRQ�6XSSRUW$�FRUH�WKHPH�RI�DOO�WKH�6SULQJ�'DWD�SURMHFWV�LV�VXSSRUW�IRU�FRQͤJXULQJ�resources to access the underlying technology. This support is implemented using XML namespaces and support classes for Spring -DYD&RQͤJ�DOORZLQJ�\RX�WR�HDVLO\�VHW�XS�DFFHVV�WR�D�0RQJR�GDWDEDVH��DQ�embedded Neo4j instance, and the like. Also, integration with core Spring functionality like JMX is provided, meaning that some stores will expose statistics through their native API, which will be exposed to JMX via Spring Data.

2EMHFW�0DSSLQJ�)UDPHZRUNMost of the NoSQL Java APIs do not provide support to map domain

JPAXML element Description<jpa:repositories /> Enables Spring Data repositories support for

repository interfaces underneath the package configured in the base-package attribute. JavaConfig equivalent is @EnableJpaRepositories.

<jpa:auditing /> Enables transparent auditing of JPA managed entities. Note that this requires the AuditingEntityListener applied to the entity (either globally through a declaration in orm.xml or through @EntityListener on the entity class).

MongoDBFor Spring Data MongoDB XML namespace elements not mentioning a GHGLFDWHG�#(QDEOH�DQQRWDWLRQ�DOWHUQDWLYH��\RX�XVXDOO\�GHFODUH�DQ�#%HDQ�annotated method and use the plain Java APIs of the classes that would have otherwise been set up by the XML element. Alternatively, you can use WKH�-DYD&RQͤJ�EDVH�FODVV�$EVWUDFW0RQJR&RQͤJXUDWLRQ�WKDW�6SULQJ�'DWD�MongoDB ships for convenience.

XML element Description<mongo:db-factory /> One stop shop to set up a Mongo

CONTENTS INCLUDE:

k�About the Spring Data Projectk�Configuration Supportk�Object Mappingk�Template APIsk�Repositoriesk�Advanced Features... and more!

Core Spring Data

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Hands on

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Sample codehttps://github.com/olivergierke/repositories-deepdive

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Step 0Initial project setup

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" How to get a Spring Data JPA based project up and running quickly?

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SummaryCheck out Spring Boot

Easily configure dependencies for your project

Defaults application config based on classpath

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Step 1Basic JPA infrastructure setup

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" Persistence technology of choice is JPA. e application uses JavaConfig and sample data contained in data.sql.

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SummaryEasy setup through JavaConfig

XML-less JPA configuration

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Step 2Quickstart

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" e implementation of the persistence layer will be based on the Spring Data repositories abstraction. Customers can be saved, looked up by their id, email address.

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SummaryInterface-based programming model

No implementation required

Queries derived from method names

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Step 3Extended CRUD methods

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" Customers can be deleted and obtained all at once.

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SummarySwitched to CrudRepository

Exposed CRUD methods

Broad API exposed

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Step 4Pagination

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" Customers can be accessed page by page.

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SummarySwitched to PagingAndSortingRepository

Exposed CRUD methods and paging ones

Broad API exposed

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Step 5Re-declaring existing CRUD methods

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" CustomerRepository.findAll() should rather return a List. e transaction timeout for save(…) should be customized to 10 seconds.

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SummaryRe-declare methods to customize

Return types

Annotation config (Tx, Locking, Query, Hints)

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Step 6Introducing a read-only repository base interface

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" Products shall be accessible in read-only mode only.

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SummaryCraft custom base interface

Return types

Narrow down the API to the necessary parts

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Step 7Using manually defined queries

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" As a user, I want to look up products by their custom attributes.

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Summary@Query annotation

JPA named queries

Spring Data named queries

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Step 8Flexible predicate execution

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" As a user, I want to search for customers by first name, last name, email address and any combination of them

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SummaryQuerydsl - type safe queries for Java

QuerydslPredicateExecutor

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Side track:Repository proxies

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Proxy mechanismUsing Spring's JDK proxy support

Bootstrap through Factory

Spring FactroyBean / CDI

XML namespace / @EnableRepositories

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Proxy mechanismQuery interface

CRUD implementation class

QueryDslPredicateExecutor

Custom implementation extension

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Step 9Custom implementations for repositories

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" As an admin user, I'd like to use custom code to delete all products beyond a given price.

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SummaryProvide custom implementation

Base class support (Querydsl)

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Stuff on topSpring MVC integration

Spring Data REST

Spring Boot

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Up and beyond

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Supported modulesJPA

MongoDB

Neo4j

Gemfire

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Community modulesSolr

Elasticsearch

Couchbase

FuzzyDB

(Cassandra)

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Further sessionsTackling Big Data Complexity with Spring - Wed, 2:30pm

Your Data, Your Search, Elasticsearch - Wed, 2:30pm

Spring Data Community Lightning Talks - Thu, 8:30am

Researching Cancer in the Cloud with Spring - Thu, 12:45pm

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Summary

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Interface-based programming model

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Start simple, getmore sophisticated

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Declarativequery execution

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Flexible predicate execution

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Customimplementation

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CDI integration

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