Core Syntax

YAML configuration provides a hierarchical structure for Spring Boot applications. Proper indentation and spacing are essential:

# Server configuration
server:
  port: 8081
  address: 0.0.0.0

# Database setup
spring:
  datasource:
    driver-class-name: com.mysql.cj.jdbc.Driver
    url: jdbc:mysql://dbhost:3306/app_db
    username: admin
    password: securepass

# Custom object mapping
employee:
  firstName: John
  lastName: Doe
  position: Developer
  experienceYears: 5

# Collection definition
programmingLanguages:
  - Java
  - Python
  - JavaScript

Advanced Configuration

YAML supports complex configurations beyond basic properties:

spring:
  datasource:
    driver-class-name: org.postgresql.Driver
    url: jdbc:postgresql://localhost:5432/prod_db
    username: dbadmin
    password: strongpassword
  servlet:
    multipart:
      max-file-size: 15MB
      max-request-size: 150MB
  web:
    resources:
      static-locations: file:/var/www/images/

# MyBatis settings
mybatis:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
    map-underscore-to-camel-case: true

# Cloud storage configuration
cloud:
  storage:
    endpoint: https://storage.example.com/api
    access-key: placeholder-access-key
    secret-key: placeholder-secret-key
    container: app-container

Properties File Equivalent

Traditional properties format compared to YAML:

File upload limits

spring.servlet.multipart.max-file-size=15MB spring.servlet.multipart.max-request-size=150MB

Static resources

spring.web.resources.static-locations=file:/var/www/images/

MyBatis configuration

mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl mybatis.configuration.map-underscore-to-camel-case=true

Cloud storage

cloud.storage.endpoint=https://storage.example.com/api cloud.storage.access-key=placeholder-access-key cloud.storage.secret-key=placeholder-secret-key cloud.storage.container=app-container

</details>