Understanding the Nuances: .yml vs .properties Files in Spring Boot

Introduction

In the realm of Spring Boot configuration, developers often encounter the choice between .yml and .properties files. Both formats serve the purpose of externalizing configuration, but they differ in syntax and features. In this comprehensive article, we will delve into the distinctions between these two file formats and provide extensive code examples to illustrate their usage in a Spring Boot application.

YAML (.yml) Files

YAML, which stands for “YAML Ain’t Markup Language” or sometimes “Yet Another Markup Language,” is a human-readable data serialization format. In the context of Spring Boot, .yml files are commonly used for configuration due to their simplicity and readability.

Example 1: Basic .yml Configuration
Let’s start with a basic example of a .yml configuration file:

# application.yml

server:
  port: 8080

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mydatabase
    username: root
    password: secret
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true

In this example, we define server properties for the embedded Tomcat server and configure a MySQL datasource for a Spring Data JPA application. The structure is hierarchical and uses indentation to represent relationships between properties.

Example 2: List and Map in .yml
YAML supports the representation of lists and maps…