hibernate / SQL Error: 0, SQLState: 08001 등

* 환경

MySQL 8

Hibernate 5

* 오류 1

hibernate  SQL Error: 0, SQLState: 08001

javax.persistence.PersistenceException: org.hibernate.exception.JDBCConnectionException: Unable to acquire JDBC Connection

...

com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server.

....

java.lang.NullPointerException

com.mysql.jdbc.ConnectionImpl.getServerCharacterEncoding(ConnectionImpl.java:3286)

* 오류 2

SQL Error: 0, SQLState: 01S00

ERROR: org.hibernate.engine.jdbc.spi.SqlExceptionHelper - The server time zone value 'KST' is unrecognized or represents more than one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.

* 오류 3(경고)

one time zone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc time zone value if you want to utilize time zone support.

Thu May 10 22:38:31 KST 2018 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore for server certificate verification.

* 해결

MySQL Connector 를 5.1.28 -> 6.05 -> 8.0.11 로 올려가면서 발생했던 오류들

- 결과적으로 MySQL 8에 mysql-connector 는 8.0.11 로 해야 했음.

- 추가적으로 다음문제 해결

http://dogcowking.tistory.com/159

* 기타

- 검토했던 다음의 해결 방안은 효과 없었음.

- <property name="hibernate.connection.release_mode">ON_CLOSE</property>

https://github.com/brettwooldridge/HikariCP/issues/1030

- 커넥션수 제한 수정

https://stackoverflow.com/questions/15813522/jdbcexceptionreporter-sql-error-0-sqlstate-08001?utm_medium=organic&utm_source=google_rich_qa&utm_campaign=google_rich_qa

- mysql 연결 주소 및 설정에 인코딩 관련 내용 추가

https://github.com/dbeaver/dbeaver/issues/1864