Methods and steps to upgrade MySql5.x to MySql8.x

spring.datasource.driver-class-name=com.mysql.jdbc.Driver
//spring.datasource.driver-class-name=com.mysql.cj.jdbc.Driver

spring.datasource.username=root //Your username. Default is root
spring.datasource.password=123456//Your password. Default is root

spring.datasource.url=jdbc:mysql://127.0.0.1:3306/sell?characterEncoding=utf-8&useSSL=false
//spring.datasource.url=jdbc:mysql://127.0.0.1:3306/sell?useUnicode=true&characterEncoding=UTF8&useSSL=false&serverTimezone=UTC

spring.jpa.show-sql=true

server.context-path=/sell
//server.servlet.context-path=/sell

<dependency>
  <groupId>mysql</groupId>
  <artifactId>mysql-connector-java</artifactId>
  <version>8.0.18</version>
</dependency>

com.mysql.cj.jdbc.Driver

# Set the time to GMT8 serverTimezone=GMT%2B8

# Full URL
String url="jdbc:mysql://"+dbHost+":"+dbPort+"/"+dbName+"?"
    + "serverTimezone=GMT%2B8&useUnicode=true&characterEncoding=utf-8"
    + "&port="+dbPort+"&autoReconnect=true";