application.properties 是这么写的

server.port=8090
server.session-timeout=30
server.context-path=
server.tomcat.max-threads=0
server.tomcat.uri-encoding=UTF-8
 
spring.datasource.url = jdbc:mysql://localhost:3306/newbirds
spring.datasource.username = root
spring.datasource.password = mymysql
spring.datasource.driverClassName = com.mysql.jdbc.Driver
# Specify the DBMS
spring.jpa.database = MYSQL
# Show or not log for each sql query
spring.jpa.show-sql = true

application.yml 如下 树状结构 视觉很好

server:
 port: 8090
 session-timeout: 30
 tomcat.max-threads: 0
 tomcat.uri-encoding: UTF-8

spring:
 datasource:
   url : jdbc:mysql://localhost:3306/newbirds
   username : root
   password : mymysql
   driverClassName : com.mysql.jdbc.Driver
 jpa:
   database : MYSQL
   show-sql : true
   hibernate:
     ddl-auto : update
     naming-strategy : org.hibernate.cfg.ImprovedNamingStrategy
   properties:
     hibernate:
       dialect : org.hibernate.dialect.MySQL5Dialect

注意点：

1，原有的key，例如spring.jpa.properties.hibernate.dialect，按“.”分割，都变成树状的配置

2，key后面的冒号，后面一定要跟一个空格

3，把原有的application.properties删掉。然后一定要执行一下 maven -X clean install