（1）springboot项目的配置文件application.properties

#配置端口号,驱动，链接，用户名，密码
server.port=9999
spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver
#注意数据库名字不要写错，否则500错误
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/springboot-vue?serverTimezone=GMT%2B8&driverClassName=com.mysql.cj.jdbc.Driver&useUnicode=true&characterEncoding=utf-8&useJDBCCompliantTimezoneShift=true&useLegacyDatetimeCode=false&serverTimezone=GMT%2B8
spring.datasource.username=root
spring.datasource.password=root