spring-orm:6 HibernateJpaVendorAdapter源码解析

版本

spring-orm:6.1.3

源码

org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter

public class HibernateJpaVendorAdapter extends AbstractJpaVendorAdapter {
   
	// 旧版本Hibernate的方言类是否存在标识
	private static final boolean oldDialectsPresent = ClassUtils.isPresent(
			"org.hibernate.dialect.PostgreSQL95Dialect", HibernateJpaVendorAdapter.class.getClassLoader());
	// jpa方言
	private final HibernateJpaDialect jpaDialect = new HibernateJpaDialect();
	...
	// 构建Jpa属性
	private Map<String, Object> buildJpaPropertyMap(boolean connectionReleaseOnClose) {
   
		Map<String, Object> jpaProperties = new HashMap<>();
		// 从 spring.jpa.database-platform 属性获取方言类名
		if (getDatabasePlatform() != null) {
   
			jpaProperties.put(AvailableSettings.DIALECT, getDatabasePlatform());
		}
		else {
   
			// 根据 spring.jpa.database 属性获取方言类
			Class<?> databaseDialectClass = determineDatabaseDialectClass(getDatabase());
			if (databaseDialectClass != null) {
   
				jpaProperties.put(AvailableSettings.DIALECT, databaseDialectClass.getName());
			}
		}
		// 如果设置了 spring.jpa.generate-ddl=true 则设置 hibernate.hbm2ddl.auto=update
		if (isGenerateDdl()) {
   
			jpaProperties.put(AvailableSettings.HBM2DDL_AUTO, "update");
		}
		// 如果设置了 spring.jpa.show-sql=true, 则设置 hibernate.show_sql=true
		if (isShowSql()) {
   
			jpaProperties.put(AvailableSettings.SHOW_SQL, "true");
		}
		// 如果需要在关闭会话时释放连接, 则设置 hibernate.connection.handling_mode=DELAYED_ACQUISITION_AND_HOLD (延迟获取，关闭会话时释放连接)
		if (connectionReleaseOnClose) {
   
			jpaProperties.put(AvailableSettings.CONNECTION_HANDLING,
					PhysicalConnectionHandlingMode.DELAYED_ACQUISITION_AND_HOLD);
		}

		// For SpringBeanContainer to be called on Hibernate 6.2
		jpaProperties.put("hibernate.cdi.extensions", "true");

		return jpaProperties;
	}
	
	// 根据数据库类型决定方言类
	protected Class<?> determineDatabaseDialectClass(Database database) {
   
		// 根据旧版本Hibernate的方言类是否存在判断Hibernate版本
		if (oldDialectsPresent) {
     // Hibernate版本低于6.2
			return switch (database) {
   
				case DB2 -> DB2Dialect.class;
				case DERBY -> DerbyTenSevenDialect.class;
				case H2 -> H2Dialect.class;
				case HANA -> HANAColumnStoreDialect.class;
				case HSQL -> HSQLDialect.class;
				case INFORMIX -> Informix10Dialect.class;
				case MYSQL -> MySQL57Dialect.class;
				case ORACLE -> Oracle12cDialect.class;
				case POSTGRESQL -> PostgreSQL95Dialect.class;
				case SQL_SERVER -> SQLServer2012Dialect.class;
				case SYBASE -> SybaseDialect.class;
				default -> null;
			};
		}
		else {
     // Hibernate版本高于6.2(包含)
			return switch (database) {
   
				case DB2 -> DB2Dialect.class;
				case DERBY -> org.hibernate.dialect.DerbyDialect.class;
				case H2 -> H2Dialect.class;
				case HANA -> HANAColumnStoreDialect.class;
				case HSQL -> HSQLDialect.class;
				case MYSQL -> MySQLDialect.class;
				case ORACLE -> OracleDialect.class;
				case POSTGRESQL -> org.hibernate.dialect.PostgreSQLDialect.class;
				case SQL_SERVER -> SQLServerDialect.class;
				case SYBASE -> SybaseDialect.class;
				default -> null;
			};
		}
	}