spring boot配置文件：.yml与.properties

SpringBoot使用一个以application命名的配置文件作为默认的全局配置文件。支持properties后缀结尾的配置文件或者以yml/yaml后缀结尾的YAML的文件配置。

application.properties：

server.port=8002
server.tomcat.uri-encoding=UTF-8
server.tomcat.max-threads=1000
server.tomcat.min-spare-threads=30
spring.application.name=test
spring.datasource.name=druidDataSource
spring.datasource.type=com.alibaba.druid.pool.DruidDataSource
spring.datasource.druid.driver-class-name=com.mysql.jdbc.Driver
spring.datasource.druid.url=jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&zeroDateTimeBehavior=convertToNull&autoReconnect=true&characterEncoding=utf-8&useSSL=false
spring.datasource.druid.username=root
spring.datasource.druid.password=root
spring.datasource.druid.filters=stat
spring.datasource.druid.max-active=100
spring.datasource.druid.initial-size=1
spring.datasource.druid.max-wait=60000
spring.datasource.druid.min-idle=1
spring.datasource.druid.time-between-eviction-runs-millis=60000
spring.datasource.druid.min-evictable-idle-time-millis=300000
spring.datasource.druid.validation-query=select 1
spring.datasource.druid.test-while-idle=true
spring.datasource.druid.test-on-borrow=false
spring.datasource.druid.test-on-return=false
spring.datasource.druid.pool-prepared-statements=true
spring.datasource.druid.max-open-prepared-statements=50
spring.datasource.druid.max-pool-prepared-statement-per-connection-size=20

application.yml：

# tomcat
server:
  port: 8002
  tomcat:
      uri-encoding: UTF-8
      max-threads: 1000
      min-spare-threads: 30
# spring boot admin
spring:
  application:
    name: test
  datasource:
      name: druidDataSource
      type: com.alibaba.druid.pool.DruidDataSource
      druid:
        driver-class-name: com.mysql.jdbc.Driver
        url: jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&zeroDateTimeBehavior=convertToNull&autoReconnect=true&characterEncoding=utf-8&useSSL=false
        username: root
        password: root
        filters: stat
        max-active: 100
        initial-size: 1
        max-wait: 60000
        min-idle: 1
        time-between-eviction-runs-millis: 60000
        min-evictable-idle-time-millis: 300000
        validation-query: select 1
        test-while-idle: true
        test-on-borrow: false
        test-on-return: false
        pool-prepared-statements: true
        max-open-prepared-statements: 50
        max-pool-prepared-statement-per-connection-size: 20

对比之后相信都看得出来，其实application.properties的功能和application.yml是一样的，不过因为yml文件是树状结构，写起来有更好的层次感，更易于理解，可读性更好一些，所以很多人都选择了yml文件。

值得注意的是同一目录下，properties配置优先级 > YAML配置优先级。

分享一个在线properties 转 yml工具，也支持yml转properties，地址：http://www.toyaml.com/index.html。