When jdbc connects to the mysql database, set the character set encoding!!!
It can be configured as follows, mysql can directly add the character set setting after the url :
String url = "jdbc:mysql://localhost:3306/exceltest1?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull";
When Mybatis connects to the mysql database, set the character set encoding!!!
It can be configured as follows, which should be written in the configuration file of Mybatis: (note to use escape & instead of &)
<property name="url" value="jdbc:mysql://localhost:3306/exceltest1?useUnicode=true&characterEncoding=UTF-8&zeroDateTimeBehavior=convertToNull"/>