尝试创建EntityManagerFactory时线程“main”org.hibernate.service.spi.ServiceException中出现异常

Question

我有h2数据库的工作应用程序。db没有连接问题，因为我可以从那里获得一些值，但是当我尝试创建EntityManagerFactory时:EntityManagerFactory emf=persistence.createEntityManagerFactory（“EmployeeService”）；然后我在日志中看到：

2020-06-04 19:22:17.901  INFO 22496 --- [           main] o.hibernate.jpa.internal.util.LogHelper  : HHH000204: Processing PersistenceUnitInfo [name: EmployeeService]
2020-06-04 19:22:17.946  WARN 22496 --- [           main] o.h.e.j.c.i.ConnectionProviderInitiator  : HHH000181: No appropriate connection provider encountered, assuming application will be supplying connections
2020-06-04 19:22:17.946  WARN 22496 --- [           main] o.h.e.j.e.i.JdbcEnvironmentInitiator     : HHH000342: Could not obtain connection to query metadata : The application must supply JDBC connections
Exception in thread "main" org.hibernate.service.spi.ServiceException: Unable to create requested service [org.hibernate.engine.jdbc.env.spi.JdbcEnvironment]
    at org.hibernate.service.internal.AbstractServiceRegistryImpl.createService(AbstractServiceRegistryImpl.java:275)
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)

#H2
spring.h2.console.enabled=true
spring.h2.console.path=/h2-console/
spring.datasource.url=jdbc:h2:mem:testdb
spring.datasource.driverClassName=org.h2.Driver
spring.datasource.username=sa
spring.datasource.password=
spring.jpa.database-platform=org.hibernate.dialect.H2Dialect

#Flyway
flyway.user=sa
flyway.password=
flyway.url=jdbc:h2:mem:testdb
flyway.locations=filesystem:db/migration
spring.flyway.baseline-on-migrate = true

<?xml version="1.0" encoding="UTF-8"?>
<persistence xmlns="http://java.sun.com/xml/ns/persistence" version="1.0">
    <persistence-unit name="EmployeeService">
        <class>com.example.demo.Employee.Employee</class>
        <properties>
            <property name="javax.persistence.jdbc.url" value="jdbc:h2:mem:testdb"/>
        <property name="javax.persistence.jdbc.driver" value="org.h2.Driver"/>
        <property name="javax.persistence.jdbc.user" value="sa"/>
        <property name="javax.persistence.jdbc.password" value=""/>
        </properties>
    </persistence-unit>
</persistence>

只有在尝试创建上面提到的EntityManagerFactory时才会出现问题。当我不尝试它时，我可以去h2 web控制台，看到flyway正确地创建了db，进行了插入，并且我可以进行选择/插入等等。

@编辑添加pom.xml

<dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-data-jpa</artifactId>
        </dependency>
        <dependency>
            <groupId>com.h2database</groupId>
            <artifactId>h2</artifactId>
            <scope>runtime</scope>
        </dependency>
        <dependency>
            <groupId>org.spingframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
        </dependency>
        <dependency>
            <groupId>org.flywaydb</groupId>
            <artifactId>flyway-core</artifactId>
        </dependency>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
            <exclusions>
                <exclusion>
                    <groupId>org.junit.vintage</groupId>
                    <artifactId>junit-vintage-engine</artifactId>
                </exclusion>
            </exclusions>
        </dependency>
    </dependencies>

Answer 1

如果检查异常，它会抱怨他没有您的persistence.xml中的方言。

请添加

<property name="hibernate.dialect" value="org.hibernate.dialect.H2Dialect"/>