报了这样一个错误，百度了一下是说mysql-connector-java版本太低导致，但是课程中版本是交给platform管理的，应该怎么改呢
java.sql.SQLException: Unknown system variable 'tx_isolation’
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2490) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2448) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1381) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.loadServerVariables(ConnectionImpl.java:3787) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:3233) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2242) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2024) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.(ConnectionImpl.java:779) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.JDBC4Connection.(JDBC4Connection.java:47) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_171]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_171]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_171]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_171]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:389) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:310) ~[tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203) ~[tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:735) [tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:667) [tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:482) [tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.(ConnectionPool.java:154) [tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118) [tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107) [tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131) [tomcat-jdbc-8.5.16.jar:na]
at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111) [spring-jdbc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77) [spring-jdbc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:394) [spring-jdbc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:443) [spring-jdbc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.security.web.authentication.rememberme.JdbcTokenRepositoryImpl.initDao(JdbcTokenRepositoryImpl.java:62) [spring-security-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.dao.support.DaoSupport.afterPropertiesSet(DaoSupport.java:48) [spring-tx-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1687) [spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1624) [spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) [spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) [spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) [spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) [spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) [spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) [spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761) [spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) [spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) [spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at com.imooc.DemoApplication.main(DemoApplication.java:16) [classes/:na]

2019-03-15 17:06:23.542 WARN 18988 — [ main] ationConfigEmbeddedWebApplicationContext : Exception encountered during context initialization - cancelling refresh attempt: org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘persistentTokenRepository’ defined in class path resource [com/imooc/security/browser/BrowserSecurityConfig.class]: Invocation of init method failed; nested exception is org.springframework.beans.factory.BeanInitializationException: Initialization of DAO failed; nested exception is org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Unknown system variable 'tx_isolation’
2019-03-15 17:06:23.546 INFO 18988 — [ main] o.apache.catalina.core.StandardService : Stopping service [Tomcat]
2019-03-15 17:06:23.555 INFO 18988 — [ main] utoConfigurationReportLoggingInitializer :

Error starting ApplicationContext. To display the auto-configuration report re-run your application with ‘debug’ enabled.
2019-03-15 17:06:23.559 ERROR 18988 — [ main] o.s.boot.SpringApplication : Application startup failed

org.springframework.beans.factory.BeanCreationException: Error creating bean with name ‘persistentTokenRepository’ defined in class path resource [com/imooc/security/browser/BrowserSecurityConfig.class]: Invocation of init method failed; nested exception is org.springframework.beans.factory.BeanInitializationException: Initialization of DAO failed; nested exception is org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Unknown system variable 'tx_isolation’
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1628) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.doCreateBean(AbstractAutowireCapableBeanFactory.java:555) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.createBean(AbstractAutowireCapableBeanFactory.java:483) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory$1.getObject(AbstractBeanFactory.java:306) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.DefaultSingletonBeanRegistry.getSingleton(DefaultSingletonBeanRegistry.java:230) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.doGetBean(AbstractBeanFactory.java:302) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractBeanFactory.getBean(AbstractBeanFactory.java:197) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.DefaultListableBeanFactory.preInstantiateSingletons(DefaultListableBeanFactory.java:761) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.finishBeanFactoryInitialization(AbstractApplicationContext.java:867) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:543) ~[spring-context-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.boot.context.embedded.EmbeddedWebApplicationContext.refresh(EmbeddedWebApplicationContext.java:122) ~[spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:693) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:360) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:303) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1118) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at org.springframework.boot.SpringApplication.run(SpringApplication.java:1107) [spring-boot-1.5.6.RELEASE.jar:1.5.6.RELEASE]
at com.imooc.DemoApplication.main(DemoApplication.java:16) [classes/:na]
Caused by: org.springframework.beans.factory.BeanInitializationException: Initialization of DAO failed; nested exception is org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Unknown system variable 'tx_isolation’
at org.springframework.dao.support.DaoSupport.afterPropertiesSet(DaoSupport.java:51) ~[spring-tx-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1687) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1624) ~[spring-beans-4.3.10.RELEASE.jar:4.3.10.RELEASE]
… 16 common frames omitted
Caused by: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is java.sql.SQLException: Unknown system variable 'tx_isolation’
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:80) ~[spring-jdbc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:394) ~[spring-jdbc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.jdbc.core.JdbcTemplate.execute(JdbcTemplate.java:443) ~[spring-jdbc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.security.web.authentication.rememberme.JdbcTokenRepositoryImpl.initDao(JdbcTokenRepositoryImpl.java:62) ~[spring-security-web-4.2.3.RELEASE.jar:4.2.3.RELEASE]
at org.springframework.dao.support.DaoSupport.afterPropertiesSet(DaoSupport.java:48) ~[spring-tx-4.3.10.RELEASE.jar:4.3.10.RELEASE]
… 18 common frames omitted
Caused by: java.sql.SQLException: Unknown system variable 'tx_isolation’
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:964) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3973) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3909) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2527) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2680) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2490) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2448) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1381) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.loadServerVariables(ConnectionImpl.java:3787) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:3233) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2242) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2024) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.(ConnectionImpl.java:779) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.JDBC4Connection.(JDBC4Connection.java:47) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) ~[na:1.8.0_171]
at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:62) ~[na:1.8.0_171]
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) ~[na:1.8.0_171]
at java.lang.reflect.Constructor.newInstance(Constructor.java:423) ~[na:1.8.0_171]
at com.mysql.jdbc.Util.handleNewInstance(Util.java:425) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:389) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:330) ~[mysql-connector-java-5.1.43.jar:5.1.43]
at org.apache.tomcat.jdbc.pool.PooledConnection.connectUsingDriver(PooledConnection.java:310) ~[tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.PooledConnection.connect(PooledConnection.java:203) ~[tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.createConnection(ConnectionPool.java:735) ~[tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.borrowConnection(ConnectionPool.java:667) ~[tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.init(ConnectionPool.java:482) ~[tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.ConnectionPool.(ConnectionPool.java:154) ~[tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.DataSourceProxy.pCreatePool(DataSourceProxy.java:118) ~[tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.DataSourceProxy.createPool(DataSourceProxy.java:107) ~[tomcat-jdbc-8.5.16.jar:na]
at org.apache.tomcat.jdbc.pool.DataSourceProxy.getConnection(DataSourceProxy.java:131) ~[tomcat-jdbc-8.5.16.jar:na]
at org.springframework.jdbc.datasource.DataSourceUtils.doGetConnection(DataSourceUtils.java:111) ~[spring-jdbc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
at org.springframework.jdbc.datasource.DataSourceUtils.getConnection(DataSourceUtils.java:77) ~[spring-jdbc-4.3.10.RELEASE.jar:4.3.10.RELEASE]
… 22 common frames omitted