使用多个数据源时，Spring boot Hibernate错误“当“Hibernate.dialent”未设置时，对方言解析信息的访问不能为null”

Question

我正在构建一个Springboot应用程序，它需要与2个不同的数据库（DB2和Oracle）进行通信。

Spring-boot-starter-父版本2.6.6

Hibernate版本5.6.7。最终的

我首先添加了DB2支持，在我在应用程序中添加了与oracle相关的设置之前，这种支持一直运行良好。下面的属性文件。

添加oracle相关设置会导致以下错误：

org.hibernate.HibernateException：对DialectResolutionInfo的访问在'hibernate.dialect'未设置时不能为空

以下是我application.properties的数据库和Hibernate相关设置：

# ==============================
# = DB2 
db2.datasource.jdbc-url=jdbc:db2://SERVER1:PORT/DATABASE-1:currentSchema=SCHEMA;
db2.datasource.username=USER1
db2.datasource.password=PASSWORD1
db2.datasource.driver-class-name=com.ibm.db2.jcc.DB2Driver
db2.jpa.properties.hibernate.dialect=org.hibernate.dialect.DB2390Dialect

# ==============================
# = ORACLE
oracle.datasource.jdbc-url=jdbc:oracle:thin:@SERVER2:PORT/DATABASE-2
oracle.datasource.username=USER2
oracle.datasource.password=PASSWORD2
oracle.jpa.properties.hibernate.dialect=org.hibernate.dialect.Oracle10gDialect

# ==============================
# = JPA / HIBERNATE
spring.jpa.hibernate.ddl-auto=update
spring.jpa.show-sql=true

我的pom。xml包含oracle和DB2的依赖项以及其他必需的依赖项：

... 
<dependency>
        <groupId>com.ibm.db2</groupId>
        <artifactId>jcc</artifactId>
        <scope>runtime</scope>
    </dependency>
    <dependency>
        <groupId>com.oracle.database.jdbc</groupId>
        <artifactId>ojdbc8</artifactId>
        <scope>runtime</scope>
    </dependency>
...

我已经将我的实体、存储库和数据源配置放入了不同的包中，因为我阅读了本文的要求https://www.javadevjournal.com/spring-boot/multiple-data-sources-with-spring-boot/.我的包结构如下所示：

project
  - dataconfig
      - db2
        - config
        - entity
        - repository
      - oracle
        - config
        - entity
        - repository

我还添加了一些实体和存储库以及我的配置类。

这是我的DB2Configuration类：

package project.dataconfig.db2.config;

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "db2EntityManagerFactory",
        transactionManagerRef = "db2TransactionManager",
        basePackages = {
                "project.dataconfig.db2.repository"
        }
)
public class Db2Configuration {

    @Primary
    @Bean(name = "db2DataSource")
    @ConfigurationProperties(prefix = "db2.datasource")
    public DataSource db2DataSource() {

        return DataSourceBuilder.create().build();
    }

    @Primary
    @Bean(name = "db2EntityManagerFactory")
    public LocalContainerEntityManagerFactoryBean entityManagerFactory(
            EntityManagerFactoryBuilder builder
            , @Qualifier("db2DataSource") DataSource dataSource) {

        return builder
                .dataSource(dataSource)
                .packages("project.dataconfig.db2.entity")
                .persistenceUnit("db2persistanceunit")
                .build();
    }

    @Primary
    @Bean(name = "db2TransactionManager")
    public PlatformTransactionManager db2TransactionManager(
      @Qualifier("db2EntityManagerFactory") EntityManagerFactory db2EntityManagerFactory) {

        return new JpaTransactionManager(db2EntityManagerFactory);
    }
}

以下是我的OracleConfiguration类：

package project.dataconfig.oracle.config;

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(
        entityManagerFactoryRef = "oracleEntityManagerFactory",
        transactionManagerRef = "oracleTransactionManager",
        basePackages = {
                "project.dataconfig.oracle.repository"
        }
)
public class OracleConfiguration {

        @Bean(name = "oracleDataSource")
        @ConfigurationProperties(prefix = "oracle.datasource")
        public DataSource oracleDataSource() {

                return DataSourceBuilder.create().build();
        }

        @Bean(name = "oracleEntityManagerFactory")
        public LocalContainerEntityManagerFactoryBean entityManagerFactory(
                EntityManagerFactoryBuilder builder
                , @Qualifier("oracleDataSource") DataSource dataSource) {

                return builder
                        .dataSource(dataSource)
                        .packages("project.dataconfig.oracle.entity")
                        .persistenceUnit("oraclepersistanceunit")
                        .build();
        }

        @Bean(name = "oracleTransactionManager")
        public PlatformTransactionManager oracleTransactionManager(
                @Qualifier("oracleEntityManagerFactory") EntityManagerFactory oracleEntityManagerFactory) {

                return new JpaTransactionManager(oracleEntityManagerFactory);
        }
}

在我在application.properties文件中添加oracle相关设置之前，我的应用程序只使用上面描述的DB2设置进行查找。

添加与oracle相关的设置和配置后，我开始出现以下错误：

org.hibernate.HibernateException：对DialectResolutionInfo的访问在'hibernate.dialect'未设置时不能为空

基于这个错误，我认为问题是由我在应用程序中对Hibernate方言的设置引起的。属性文件。我认为这是两种设置之一造成的

...
db2.jpa.properties.hibernate.dialect=org.hibernate.dialect.DB2390Dialect

...
oracle.jpa.properties.hibernate.dialect=org.hibernate.dialect.Oracle10gDialect

如何解决此问题？

Answer 1

我弄明白了。

修改Db2Configuration和OracleConfiguration的方法entityManagerFactory，为他们提供有关hibernate方言的信息：

对于DB2

@Primary
@Bean(name = "db2EntityManagerFactory")
public LocalContainerEntityManagerFactoryBean entityManagerFactory(
        EntityManagerFactoryBuilder builder
        , @Qualifier("db2DataSource") DataSource dataSource) {

    final HashMap<String, Object> hibernateProperties = new HashMap<String, Object>();
    hibernateProperties.put("hibernate.dialect", "org.hibernate.dialect.DB2390Dialect");

    return builder
            .dataSource(dataSource)
            .packages("project.dataconfig.db2.entity")
            .properties(hibernateProperties)
            .persistenceUnit("db2persistanceunit")
            .build();
}

对于Oracle

@Bean(name = "oracleEntityManagerFactory")
public LocalContainerEntityManagerFactoryBean entityManagerFactory(
        EntityManagerFactoryBuilder builder
        , @Qualifier("oracleDataSource") DataSource dataSource) {

    final HashMap<String, Object> hibernateProperties = new HashMap<String, Object>();
    hibernateProperties.put("hibernate.dialect", "org.hibernate.dialect.Oracle10gDialect");

    return builder
            .dataSource(dataSource)
            .packages("project.dataconfig.oracle.entity")
            .properties(hibernateProperties)
            .persistenceUnit("oraclepersistanceunit")
            .build();
}

在此之后，我的控制台在运行应用程序时显示，指示一切正常：

HHH000400: Using dialect: org.hibernate.dialect.DB2390Dialect
 Initialized JPA EntityManagerFactory for persistence unit 'db2persistanceunit'
HHH000204: Processing PersistenceUnitInfo [name: oraclepersistanceunit]
HHH000400: Using dialect: org.hibernate.dialect.Oracle10gDialect
Initialized JPA EntityManagerFactory for persistence unit 'oraclepersistanceunit'

我的执行器 /healthendpoint也将这两个数据库视为已启动并正在运行。