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Properties ↔ YAML Converter

A tool for converting Spring Boot's application.properties and application.yml files. Essential for configuration file migration and refactoring!

📄 Properties → YAML

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💡 Spring Boot Configuration Tips

Properties 장점:
  • 간단하고 직관적
  • 한 줄에 하나의 설정
  • 검색하기 쉬움
YAML 장점:
  • 계층 구조가 명확
  • 중복 줄임
  • 가독성 좋음
주의사항:
  • YAML은 들여쓰기에 민감 (스페이스만 사용)
  • Properties는 특수문자 이스케이프 필요
  • Profile별 파일 분리 권장

Properties vs YAML​

Properties Format​

spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=root
spring.datasource.password=secret
server.port=8080

YAML Format​

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mydb
    username: root
    password: secret
server:
  port: 8080

When to Use?​

Properties → YAML Conversion​

  • When migrating projects to YAML
  • When you want to see hierarchical structure clearly
  • When you want to reduce duplicate prefixes
  • When you want to improve readability

YAML → Properties Conversion​

  • Compatibility with legacy systems
  • Preference for simple configuration
  • Easier searching and grepping
  • Better IDE auto-completion

Real-World Examples​

Database Configuration​

Properties:

# Database Configuration
spring.datasource.url=jdbc:mysql://localhost:3306/mydb
spring.datasource.username=root
spring.datasource.password=secret123
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

YAML:

# Database Configuration
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mydb
    username: root
    password: secret123
    driver-class-name: com.mysql.cj.jdbc.Driver
  jpa:
    hibernate:
      ddl-auto: update
    show-sql: true

Server & Logging Configuration​

Properties:

server.port=8080
server.servlet.context-path=/api
server.compression.enabled=true

logging.level.root=INFO
logging.level.com.example=DEBUG
logging.file.name=logs/application.log
logging.pattern.console=%d{yyyy-MM-dd HH:mm:ss} - %msg%n

YAML:

server:
  port: 8080
  servlet:
    context-path: /api
  compression:
    enabled: true

logging:
  level:
    root: INFO
    com.example: DEBUG
  file:
    name: logs/application.log
  pattern:
    console: '%d{yyyy-MM-dd HH:mm:ss} - %msg%n'

Complex Properties​

Properties:

spring.kafka.bootstrap-servers=localhost:9092
spring.kafka.consumer.group-id=my-group
spring.kafka.consumer.auto-offset-reset=earliest
spring.kafka.consumer.key-deserializer=org.apache.kafka.common.serialization.StringDeserializer
spring.kafka.consumer.value-deserializer=org.apache.kafka.common.serialization.StringDeserializer

YAML:

spring:
  kafka:
    bootstrap-servers: localhost:9092
    consumer:
      group-id: my-group
      auto-offset-reset: earliest
      key-deserializer: org.apache.kafka.common.serialization.StringDeserializer
      value-deserializer: org.apache.kafka.common.serialization.StringDeserializer

Properties vs YAML Comparison​

✅ Properties Advantages​

  1. Simplicity: One setting per line
  2. Easy Search: Easy to find with grep
  3. Familiarity: Old Java standard
  4. Special Characters: Easy to escape

✅ YAML Advantages​

  1. Readability: Clear hierarchical structure
  2. Reduce Duplication: Common prefixes omitted
  3. Comments: More flexible comments
  4. Lists: Can express arrays

⚠️ Properties Disadvantages​

  • Lots of duplication
  • Difficult to understand hierarchical structure
  • Complex configurations become lengthy

⚠️ YAML Disadvantages​

  • Sensitive to indentation
  • Cannot use tabs (spaces only)
  • Difficult to debug parsing errors

Differences in Spring Boot​

Profile Usage​

Properties:

# application.properties (common)
app.name=MyApp

# application-dev.properties (development)
spring.datasource.url=jdbc:mysql://localhost:3306/dev_db

# application-prod.properties (production)
spring.datasource.url=jdbc:mysql://prod-server:3306/prod_db

YAML (Profile separation in one file):

app:
  name: MyApp

---
spring:
  config:
    activate:
      on-profile: dev
  datasource:
    url: jdbc:mysql://localhost:3306/dev_db

---
spring:
  config:
    activate:
      on-profile: prod
  datasource:
    url: jdbc:mysql://prod-server:3306/prod_db

List/Array Expression​

Properties (using index):

app.servers[0]=server1.example.com
app.servers[1]=server2.example.com
app.servers[2]=server3.example.com

YAML (native array):

app:
  servers:
    - server1.example.com
    - server2.example.com
    - server3.example.com

Map Structure​

Properties:

app.config.key1=value1
app.config.key2=value2
app.config.key3=value3

YAML:

app:
  config:
    key1: value1
    key2: value2
    key3: value3

Usage Tips​

1. Gradual Migration​

# 1. Backup existing properties
cp application.properties application.properties.bak

# 2. Convert to YAML
# (Use this tool)

# 3. Create application.yml

# 4. Delete properties after testing

2. Profile Separation​

# application.yml (common settings only)
app:
  name: MyApp

# application-dev.yml (development environment)
# application-prod.yml (production environment)

3. Use Environment Variables for Sensitive Information​

spring:
  datasource:
    password: ${DB_PASSWORD}  # Use environment variable

4. Utilize IDE Plugins​

  • IntelliJ IDEA: Spring Boot support
  • VS Code: Spring Boot Extension Pack
  • Utilize auto-completion and validation features

Precautions​

When Writing YAML​

# ❌ Wrong example (using tab)
spring:
	datasource:  # Using tab - Error!

# ✅ Correct example (using spaces)
spring:
  datasource:  # 2 spaces

Special Character Handling​

Properties:

# Escape special characters with backslash
app.message=Hello\nWorld
app.path=C:\\Users\\Example

YAML:

# Wrap with quotes
app:
  message: "Hello\nWorld"
  path: "C:\\Users\\Example"

Numbers and Booleans​

Properties:

server.port=8080
app.enabled=true

YAML (automatic type conversion):

server:
  port: 8080        # Recognized as number
  port: "8080"      # Keep as string
app:
  enabled: true     # boolean
  enabled: "true"   # string

Troubleshooting​

Errors After Conversion​

  1. Check YAML Indentation

    • Use 2 spaces
    • Check for no tab characters

  2. Check Special Characters

    • Wrap :, #, @, etc. with quotes

  3. Check Types

    • Verify numbers and booleans are converted as intended

  4. Check Profile Settings

    • spring.profiles.active configuration

Additional Resources​

Best Practices​

1. Separate by Environment​

application.yml          # Common settings
application-dev.yml      # Development environment
application-test.yml     # Test environment
application-prod.yml     # Production environment

2. Externalize Sensitive Information​

spring:
  datasource:
    password: ${DB_PASSWORD:defaultPassword}

3. Use Comments​

# Database Configuration
# Separate configuration needed in production environment
spring:
  datasource:
    url: jdbc:mysql://localhost:3306/mydb

4. Consistent Naming​

# Kebab case recommended
spring:
  data-source:  # ✅
    driver-class-name: ...

# Avoid camel case
spring:
  dataSource:  # ❌
    driverClassName: ...