PROSAGA码农传奇-springboot-org.hibernate.HibernateException：如果未设置“ hibernate.dialect”，则对DialectResolutionInfo的访问不能为null

我正在尝试运行一个通过spring-jpa使用休眠模式的spring-boot应用程序，但出现此错误：
<pre><code>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:104)
 at org.hibernate.engine.jdbc.dialect.internal.DialectFactoryImpl.buildDialect(DialectFactoryImpl.java:71)
 at org.hibernate.engine.jdbc.internal.JdbcServicesImpl.configure(JdbcServicesImpl.java:205)
 at org.hibernate.boot.registry.internal.StandardServiceRegistryImpl.configureService(StandardServiceRegistryImpl.java:111)
 at org.hibernate.service.internal.AbstractServiceRegistryImpl.initializeService(AbstractServiceRegistryImpl.java:234)
 at org.hibernate.service.internal.AbstractServiceRegistryImpl.getService(AbstractServiceRegistryImpl.java:206)
 at org.hibernate.cfg.Configuration.buildTypeRegistrations(Configuration.java:1885)
 at org.hibernate.cfg.Configuration.buildSessionFactory(Configuration.java:1843)
 at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:850)
 at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl$4.perform(EntityManagerFactoryBuilderImpl.java:843)
 at org.hibernate.boot.registry.classloading.internal.ClassLoaderServiceImpl.withTccl(ClassLoaderServiceImpl.java:398)
 at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:842)
 at org.hibernate.jpa.HibernatePersistenceProvider.createContainerEntityManagerFactory(HibernatePersistenceProvider.java:152)
 at org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean.createNativeEntityManagerFactory(LocalContainerEntityManagerFactoryBean.java:336)
 at org.springframework.orm.jpa.AbstractEntityManagerFactoryBean.afterPropertiesSet(AbstractEntityManagerFactoryBean.java:318)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.invokeInitMethods(AbstractAutowireCapableBeanFactory.java:1613)
 at org.springframework.beans.factory.support.AbstractAutowireCapableBeanFactory.initializeBean(AbstractAutowireCapableBeanFactory.java:1550)
 ... 21 more
</code></pre>我的pom.xml文件是这样的：
<pre><code><parent>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-parent</artifactId>
 <version>1.1.8.RELEASE</version>
</parent>

<dependencies>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-web</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-actuator</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.security</groupId>
 <artifactId>spring-security-web</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.security</groupId>
 <artifactId>spring-security-config</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.security</groupId>
 <artifactId>spring-security-taglibs</artifactId>
 </dependency>
 <dependency>
 <groupId>org.springframework.boot</groupId>
 <artifactId>spring-boot-starter-data-jpa</artifactId>
 </dependency>
 <dependency>
 <groupId>commons-dbcp</groupId>
 <artifactId>commons-dbcp</artifactId>
 </dependency>
</dependencies>
</code></pre>我的休眠配置是（方言配置位于此类的最后一个方法中）：
<pre><code>@Configuration
@EnableTransactionManagement
@ComponentScan({ "com.spring.app" })
public class HibernateConfig {

@Bean
   public LocalSessionFactoryBean sessionFactory() {
      LocalSessionFactoryBean sessionFactory = new LocalSessionFactoryBean();

sessionFactory.setDataSource(restDataSource());
      sessionFactory.setPackagesToScan(new String[] { "com.spring.app.model" });
      sessionFactory.setHibernateProperties(hibernateProperties());

return sessionFactory;
   }

@Bean
   public DataSource restDataSource() {
      BasicDataSource dataSource = new BasicDataSource();

dataSource.setDriverClassName("org.postgresql.Driver");
      dataSource.setUrl("jdbc:postgresql://localhost:5432/teste?charSet=LATIN1");
      dataSource.setUsername("klebermo");
      dataSource.setPassword("123");

return dataSource;
   }

@Bean
   @Autowired
   public HibernateTransactionManager transactionManager(SessionFactory sessionFactory) {
      HibernateTransactionManager txManager = new HibernateTransactionManager();
      txManager.setSessionFactory(sessionFactory);
      return txManager;
   }

@Bean
   public PersistenceExceptionTranslationPostProcessor exceptionTranslation() {
      return new PersistenceExceptionTranslationPostProcessor();
   }

Properties hibernateProperties() {
      return new Properties() {
         /**
         * 
         */
        private static final long serialVersionUID = 1L;

{
 setProperty("hibernate.hbm2ddl.auto", "create");
 setProperty("hibernate.show_sql", "false");
 setProperty("hibernate.dialect", "org.hibernate.dialect.PostgreSQLDialect");
 }
 };
 }
}
</code></pre>我在这里做错了什么？

首先删除所有配置，Spring Boot将为您启动它。

确保您application.properties的类路径中有一个，然后添加以下属性。

```
spring.datasource.url=jdbc:postgresql://localhost:5432/teste?charSet=LATIN1
spring.datasource.username=klebermo
spring.datasource.password=123

spring.jpa.database-platform=org.hibernate.dialect.PostgreSQLDialect
spring.jpa.show-sql=false
spring.jpa.hibernate.ddl-auto=create
```

如果您确实需要访问，SessionFactory并且基本上是针对同一数据源的，则可以执行以下操作（尽管对于XML而不是JavaConfig，也可以在此处进行记录）。

```
@Configuration        
public class HibernateConfig {

@Bean
    public HibernateJpaSessionFactoryBean sessionFactory(EntityManagerFactory emf) {
         HibernateJpaSessionFactoryBean factory = new HibernateJpaSessionFactoryBean();
         factory.setEntityManagerFactory(emf);
         return factory;
    }
}
```

这样，您就可以同时拥有EntityManagerFactory和SessionFactory。

更新：从Hibernate 5开始，它SessionFactory实际上扩展了EntityManagerFactory。因此，要获取一个，SessionFactory您可以简单地将其强制转换EntityManagerFactory为它或使用该unwrap方法来获取一个。

public class SomeHibernateRepository {

@PersistenceUnit
  private EntityManagerFactory emf;

protected SessionFactory getSessionFactory() {
    return emf.unwrap(SessionFactory.class);
  }

}
假设您有一个带有main方法的类，@EnableAutoConfiguration则不需要@EnableTransactionManagement注释，因为Spring Boot将为您启用该注释。程序com.spring.app包中的基本应用程序类就足够了。

```
@Configuration
@EnableAutoConfiguration
@ComponentScan
public class Application {

public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class, args);
    }

} 
```

这样的事情应该足以检测到您的所有类（包括实体和基于Spring Data的存储库）。

更新：这些注释可以@SpringBootApplication在Spring Boot的最新版本中替换为一个。

```
@SpringBootApplication
public class Application {

public static void main(String[] args) throws Exception {
        SpringApplication.run(Application.class, args);
    }
} 
```
我还建议删除commons-dbcp依赖关系，因为这将允许Spring Boot配置更快，更可靠的HikariCP实现。