回答问题的时间太晚了.但我希望它对其他人有用...

Little late to answer the question. But I hope it will be useful for others...

以上配置使数据库表存储utf8编码的数据.但是，数据库连接(JDBC)应该能够将utf8编码的数据传输到客户端.为此，应将JDBC连接参数字符集设置为 utf8mb4 .

Above configuration makes the database tables to store utf8 encoded data. But, the database connection(JDBC) should be able to transfer the utf8 encoded data to client. For that the JDBC connection parameter charset should be set to utf8mb4.