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<div style='display: inline'> <h1 style='font-family: Malgun Gothic, Consolas; font-size: 20pt; color: #006699; text-align: center; font-weight: bold'>java.lang.NullPointerException - com.mysql.jdbc.ConnectionImpl.getServerCharset</h1> <p> Spring Framework에서 JDBC로 mysql에 접근했는데 다음과 같은 오류가 발생합니다.<br /> <br /> <pre style='margin: 10px 0px 10px 10px; padding: 10px 0px 10px 10px; background-color: #fbedbb; overflow: auto; font-family: Consolas, Verdana;' > HTTP Status 500 – Internal Server Error Type Exception Report Message Request processing failed; nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException: Description The server encountered an unexpected condition that prevented it from fulfilling the request. Exception org.springframework.web.util.NestedServletException: Request processing failed; nested exception is org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException: ### Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Could not create connection to database server.) ### The error may exist in org/example/repository/UserMapper.java (best guess) ### The error may involve org.example.repository.UserMapper.selectAll ### The error occurred while executing a query ### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Could not create connection to database server.) ...[생략]... org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) Root Cause org.mybatis.spring.MyBatisSystemException: nested exception is org.apache.ibatis.exceptions.PersistenceException: ### Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Could not create connection to database server.) ### The error may exist in org/example/repository/UserMapper.java (best guess) ### The error may involve org.example.repository.UserMapper.selectAll ### The error occurred while executing a query ### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Could not create connection to database server.) org.mybatis.spring.MyBatisExceptionTranslator.translateExceptionIfPossible(MyBatisExceptionTranslator.java:75) ...[생략]... org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) Root Cause org.apache.ibatis.exceptions.PersistenceException: ### Error querying database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Could not create connection to database server.) ### The error may exist in org/example/repository/UserMapper.java (best guess) ### The error may involve org.example.repository.UserMapper.selectAll ### The error occurred while executing a query ### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Could not create connection to database server.) org.apache.ibatis.exceptions.ExceptionFactory.wrapException(ExceptionFactory.java:26) ...[생략]... org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) Root Cause org.springframework.jdbc.CannotGetJdbcConnectionException: Failed to obtain JDBC Connection; nested exception is org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Could not create connection to database server.) org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:82) ...[생략]... org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) Root Cause org.apache.commons.dbcp.SQLNestedException: Cannot create PoolableConnectionFactory (Could not create connection to database server.) org.apache.commons.dbcp.BasicDataSource.createPoolableConnectionFactory(BasicDataSource.java:1549) ...[생략]... org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) Root Cause com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Could not create connection to database server. java.base/jdk.internal.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ...[생략]... org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) Root Cause java.lang.NullPointerException com.mysql.jdbc.ConnectionImpl.getServerCharset(ConnectionImpl.java:2983) ...[생략]... org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:52) Note The full stack trace of the root cause is available in the server logs. </pre> <br /> 마지막 오류가 com.mysql.jdbc.ConnectionImpl.getServerCharset 메서드 호출에 "java.lang.NullPointerException" 예외가 발생한 것인데요, 이때의 구성은 다음과 같았습니다.<br /> <br /> <pre style='margin: 10px 0px 10px 10px; padding: 10px 0px 10px 10px; background-color: #fbedbb; overflow: auto; font-family: Consolas, Verdana;' > // pom.xml <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version><a target='tab' href='https://mvnrepository.com/artifact/mysql/mysql-connector-java'>8.0.26</a></version> </dependency> </pre> <br /> <pre style='margin: 10px 0px 10px 10px; padding: 10px 0px 10px 10px; background-color: #fbedbb; overflow: auto; font-family: Consolas, Verdana;' > // applicationContext.xml <bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource"> <property name="driverClassName" value="com.mysql.jdbc.Driver" /> <property name="url" value="jdbc:mysql://localhost:3306/test?serverTimezone=Asia/Seoul&amp;useSSL=false" /> <property name="username" value="..." /> <property name="password" value="..." /> </bean> </pre> <br /> 사실 이전에 테스트했던 콘솔 프로그램에서도 마찬가지의 오류가 발생하는데,<br /> <br /> <pre style='margin: 10px 0px 10px 10px; padding: 10px 0px 10px 10px; background-color: #fbedbb; overflow: auto; font-family: Consolas, Verdana;' > Java에서 MySQL 사용 ; <a target='tab' href='https://www.sysnet.pe.kr/2/0/1127'>https://www.sysnet.pe.kr/2/0/1127</a> </pre> <br /> 그사이 다음과 같은 변화가 있었다고 합니다.<br /> <br /> <pre style='margin: 10px 0px 10px 10px; padding: 10px 0px 10px 10px; background-color: #fbedbb; overflow: auto; font-family: Consolas, Verdana;' > mysql-connector-java 6.xx대로 변경시 주의 사항 ; <a target='tab' href='https://effectivesquid.tistory.com/entry/mysqlconnectorjava-6xx%EB%8C%80%EB%A1%9C-%EB%B3%80%EA%B2%BD%EC%8B%9C-%EC%A3%BC%EC%9D%98-%EC%82%AC%ED%95%AD'>https://effectivesquid.tistory.com/entry/mysqlconnectorjava-6xx%EB%8C%80%EB%A1%9C-%EB%B3%80%EA%B2%BD%EC%8B%9C-%EC%A3%BC%EC%9D%98-%EC%82%AC%ED%95%AD</a> </pre> <br /> 그래서, driverClassName을 "com.mysql.cj.jdbc.Driver"로 바꿔야 한다고.<br /> <br /> <pre style='margin: 10px 0px 10px 10px; padding: 10px 0px 10px 10px; background-color: #fbedbb; overflow: auto; font-family: Consolas, Verdana;' > <property name="driverClassName" value="<span style='color: blue; font-weight: bold'>com.mysql.cj.jdbc.Driver</span>" /> </pre> </p><br /> <br /><hr /><span style='color: Maroon'>[이 글에 대해서 여러분들과 의견을 공유하고 싶습니다. 틀리거나 미흡한 부분 또는 의문 사항이 있으시면 언제든 댓글 남겨주십시오.]</span> </div>
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