数据库：utf8mb4
字段： utf8mb4 utf8mb4_unicode_ci
connection：
datasource.url=jdbc:mysql://127.0.0.1:3306/test?useUnicode=true&autoReconnect=true&zeroDateTimeBehavior=convertToNull
datasource.username=root
datasource.password=root
datasource.show-sql=true
datasource.initSQL=SET NAMES 'utf8mb4' COLLATE utf8mb4_unicode_ci
datasource.driverClassName=com.mysql.jdbc.Driver
