Can't translate sql errorcode if throws MetaDataAccessException at building SQLErrorCodeSQLExceptionTranslator with DataSource parameter

[zrlw]

Affects: \5.2.5.RELEASE(spring-jdbc)

mysql-connector-java: 8.0.19
mybatis-spring-boot-starter: 2.1.2
spring-boot-starter-jdbc: 2.2.6.RELEASE

step 1: set mysql to read only
$ mysql -uroot -p
mysql> set global read_only=ON;
mysql> flush tables with read lock;

step 2: write a test application which inserts a record into the test table.
SQLErrorCodeSQLExceptionTranslator object will be built with datasource input parameter, MetaDataAccessException will be triggered at JdbcUtils.extractDatabaseMetaData call, and a new SQLErrorCodes() will be built as the sqlErrorCodes of the SQLErrorCodeSQLExceptionTranslator object.

step 3: set mysql to read/write
$ mysql -uroot -p
mysql> set global read_only=OFF;
mysql> unlock tables;

step4: continue the test application to insert two same records into the test table which has unique key.
the SQLErrorCodeSQLExceptionTranslator object could not do anything but return null because it;s sqlErrorCodes has empty duplicateKeyCodes.

[zrlw]

we fix it by calling setDataSource(dataSource) again at the beginning of doTranslate() of SQLErrorCodeSQLExceptionTranslator.

[zrlw]

same with #25681