Book Image

Spring Data

By : Petri Kainulainen
Book Image

Spring Data

By: Petri Kainulainen

Overview of this book

Spring Framework has always had a good support for different data access technologies. However, developers had to use technology-specific APIs, which often led to a situation where a lot of boilerplate code had to be written in order to implement even the simplest operations. Spring Data changed all this. Spring Data makes it easier to implement Spring-powered applications that use cloud-based storage services, NoSQL databases, map-reduce frameworks or relational databases. "Spring Data" is a practical guide that is full of step-by-step instructions and examples which ensure that you can start using the Java Persistence API and Redis in your applications without extra hassle. This book provides a brief introduction to the underlying data storage technologies, gives step-by-step instructions that will help you utilize the discussed technologies in your applications, and provides a solid foundation for expanding your knowledge beyond the concepts described in this book. You will learn an easier way to manage your entities and to create database queries with Spring Data JPA. This book also demonstrates how you can add custom functions to your repositories. You will also learn how to use the Redis key-value store as data storage and to use its other features for enhancing your applications. "Spring Data" includes all the practical instructions and examples that provide you with all the information you need to create JPA repositories with Spring Data JPA and to utilize the performance of Redis in your applications by using Spring Data Redis.
Table of Contents (13 chapters)

Building queries

There are three options we can use to build queries with Spring Data JPA: query methods, JPA Criteria API, and Querydsl. During this section, we will learn how to use them and start the implementation of our search function. We will also take a look at the pros and cons of each option and receive concrete recommendations concerning the selection of the correct query creation technique.

Before we can move forward, we have to add a search() method, which is used as a starting point of our search function, to the ContactService interface. The signature of the search() method looks like the following code snippet:

public List<Contact> search(String searchTerm);

Query methods

The simplest way to create queries with Spring Data JPA is to use query methods. Query methods are methods that are declared in the repository interface. There are three techniques we can use to create query methods:

  • Query generation from method name

  • Named Queries

  • The @Query annotation

Query generation...