Spring Boot: Up and Running

Chapter 4. Adding Database Access to Your Spring Boot App

As discussed in the previous chapter, applications often expose stateless APIs for many very good reasons. Behind the scenes, however, very few useful applications are entirely ephemeral; state of some kind is usually stored for something. For example, every request to an online store’s shopping cart may well include its state, but once the order is placed, that order’s data is kept. There are many ways to do this, and many ways to share or route this data, but invariably there are one or more databases involved within nearly all systems of sufficient size.

In this chapter, I’ll demonstrate how to add database access to the Spring Boot application created in the previous chapter. This chapter is meant to be a short primer on Spring Boot’s data capabilities, and subsequent chapters will dive much deeper. But in many cases, the basics covered here still apply well and provide a fully sufficient solution. Let’s dig in.

Code Checkout Checkup

Please check out branch chapter4begin from the code repository to begin.

Priming Autoconfig for Database Access

As demonstrated earlier, Spring Boot aims to simplify to the maximum extent possible the so-called 80–90% use case: the patterns of code and process that developers do over and over and over again. Once patterns are identified, Boot springs into action to initialize the required beans automatically, with sensible default configurations. Customizing a capability is as simple ...