注意：以下配置仅适用于新建的数据库，如果您的数据库已创建，则需要修改库和表，具体修改流程参考以下链接
https://mathiasbynens.be/notes/mysql-utf8mb4
application.properties配置
spring.datasource.connectionInitSql=SET NAMES 'utf8mb4'
application.yml配置
spring:
datasource:
connectionInitSql: "SET NAMES 'utf8mb4'"
mysql配置
vi /etc/my.cnf
[client]
default-character-set=utf8mb4
[mysql]
default-character-set=utf8mb4
[mysqld]
collation-server = utf8mb4_unicode_ci
init-connect='SET NAMES utf8mb4'
character-set-server = utf8mb4
