那么, 如果你非得要替换到这个默认的实现, 或者, 更进一步, 例如你想要替换掉某一个Service的标准实现, 异或, 你想把自己写的service也添加到service registry当中呢
更进一步来看看Service
首先, BootstrapServiceRegistry中所提供的service是固定的, 无法增减, 除非你提供一个自己的 org.hibernate.boot.registry.internal.BootstrapServiceRegistryImpl 实现类, 但是并不推荐.
从org.hibernate.boot.registry.internal.BootstrapServiceRegistryImpl#locateServiceBinding 方法中我们可以看到BootStrapServiceRegistry所提供的标准服务.
public ServiceBinding locateServiceBinding(Class serviceRole) {
if ( ClassLoaderService.class.equals( serviceRole ) ) {
return (ServiceBinding) classLoaderServiceBinding;
}
else if ( StrategySelector.class.equals( serviceRole) ) {
return (ServiceBinding) strategySelectorBinding;
}
else if ( IntegratorService.class.equals( serviceRole ) ) {
return (ServiceBinding) integratorServiceBinding;
}
return null;
}
推荐的扩展位置是 ServiceRegistry, 在这里, 你可以增加你自定义的service, 替换标准的service实现等等.
ServiceRegistry 中所提供的标准服务是定义在 org.hibernate.service.StandardServiceInitiators 当中:
public class StandardServiceInitiators {
public static List LIST = buildStandardServiceInitiatorList();
private static List buildStandardServiceInitiatorList() {
final List serviceInitiators = new ArrayList();
serviceInitiators.add( ConfigurationServiceInitiator.INSTANCE );
serviceInitiators.add( ImportSqlCommandExtractorInitiator.INSTANCE );
serviceInitiators.add( JndiServiceInitiator.INSTANCE );
serviceInitiators.add( JmxServiceInitiator.INSTANCE );
serviceInitiators.add( PersisterClassResolverInitiator.INSTANCE );
serviceInitiators.add( PersisterFactoryInitiator.INSTANCE );
serviceInitiators.add( ConnectionProviderInitiator.INSTANCE );
serviceInitiators.add( MultiTenantConnectionProviderInitiator.INSTANCE );
serviceInitiators.add( DialectResolverInitiator.INSTANCE );
serviceInitiators.add( DialectFactoryInitiator.INSTANCE );
serviceInitiators.add( BatchBuilderInitiator.INSTANCE );
serviceInitiators.add( JdbcEnvironmentInitiator.INSTANCE );
serviceInitiators.add( JdbcServicesInitiator.INSTANCE );
serviceInitiators.add( RefCursorSupportInitiator.INSTANCE );
serviceInitiators.add( SchemaManagementToolInitiator.INSTANCE );
serviceInitiators.add( MutableIdentifierGeneratorFactoryInitiator.INSTANCE);
serviceInitiators.add( JtaPlatformInitiator.INSTANCE );
serviceInitiators.add( TransactionFactoryInitiator.INSTANCE );
serviceInitiators.add( SessionFactoryServiceRegistryFactoryInitiator.INSTANCE );
return Collections.unmodifiableList( serviceInitiators );
}
}
可以看到, 每一个标准服务都被封装成了 StandardServiceInitiator, 那么什么是 ServiceInitiator 呢
ServiceInitiator
org.hibernate.service.spi.ServiceInitiator
定义了一个 Service 的加载器, 这个接口里面只有一个方法
/**
* Obtains the service role initiated by this initiator. Should be unique within a registry
*
* @return The service role.
*/