解决 Caused by: org.hibernate.HibernateException: Access to DialectResolutionInfo cannot b
遇到异常不能只看片面，要看头看尾。
异常信息：
java.sql.SQLSyntaxErrorException: Unknown database 'library'
......中建省略600行
Caused by: org.hibernate.HibernateException: Access to DialectResolutionInfo cannot be null when 'hibernate.dialect' not set
at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.determineDialect(DialectFactoryImpl.java:100) ~[hibernate-core-5.6.1.Final.jar:5.6.1.Final]
at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:54) ~[hibernate-core-5.6.1.Final.jar:5.6.1.Final]
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:138) ~[hibernate-core-5.6.1.Final.jar:5.6.1.Final]
at org.hibernate.engine.jdbc.env.internal.JdbcEnvironmentInitiator.initiateService(JdbcEnvironmentInitiator.java:35) ~[hibernate-core-5.6.1.Final.jar:5.6.1.Final]
at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.initiateService(StandardServiceRegistryImpl.java:101) ~[hibernate-core-5.6.1.Final.jar:5.6.1.Final]
at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:263) ~[hibernate-core-5.6.1.Final.jar:5.6.1.Final]
... 101 common frames omitted
不能只看到最后的HibernateException就认为hibernate jpa这些出了问题，还要往前看。
我的问题是没有创建数据库library，但是却在application.yml文件中url连接library了:
datasource:
url: jdbc:mysql://localhost:3306/library?useUnicode=true&useSSL=false&characterEncoding=utf8&serverTimezone=Asia/Shanghai