mysql錯誤：this authentication plugin is not supported
this authentication plugin is not supported
應用程式連線mysql docker一直報錯：this authentication plugin is not supported。
google發現，原來是mysql新版本（8.0以上）將root使用者使用的plugin更新成caching_sha2_password。
登入mysql輸入如下命令可以看到：
mysql> select user,plugin from mysql.user;
+------------------+-----------------------+
| user | plugin |
+------------------+-----------------------+
| root | caching_sha2_password |
| mysql.infoschema | mysql_native_password |
| mysql.session | mysql_native_password |
| mysql.sys | mysql_native_password |
| root | caching_sha2_password |
+------------------+-----------------------+
解決辦法有：
（1）降級，使用老版本mysql。
（2）將root的plugin改成mysql_native_password。
這裡改成：
ALTER USER ‘root’@’localhost’ IDENTIFIED WITH mysql_native_password BY ‘root’;
這行程式碼有兩層含義，第一:修改root的密碼為’root’，摒棄原來的舊密碼。第二：使用mysql_native_password對新密碼進行編碼。
然後再啟動應用，還是一樣報錯。再看mysql.user,發現還有一個host”%”的root使用者：
mysql> select host,user,plugin from mysql.user;
+-----------+------------------+-----------------------+
| host | user | plugin |
+-----------+------------------+-----------------------+
| % | root | caching_sha2_password |
| localhost | mysql.infoschema | mysql_native_password |
| localhost | mysql.session | mysql_native_password |
| localhost | mysql.sys | mysql_native_password |
| localhost | root | mysql_native_password |
+-----------+------------------+-----------------------+
5 rows in set (0.00 sec)
將這個使用者也改了：
ALTER USER ‘root’@’%’ IDENTIFIED WITH mysql_native_password BY ‘root’;
再看：
mysql> select host,user,plugin from mysql.user;
+-----------+------------------+-----------------------+
| host | user | plugin |
+-----------+------------------+-----------------------+
| % | root | mysql_native_password |
| localhost | mysql.infoschema | mysql_native_password |
| localhost | mysql.session | mysql_native_password |
| localhost | mysql.sys | mysql_native_password |
| localhost | root | mysql_native_password |
+-----------+------------------+-----------------------+
改成功了，再啟動應用，報錯：
this user requires mysql native password authentication
在連線mysql的url上加上?allowNativePasswords=true
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