Spring Boot 2转3（Hibernate5升6）：registerFunction被移除的适配问题

在Hibernate 6中，原Dialect类的registerFunction方法已被移除，替代方案是通过重写initializeFunctionRegistry方法或直接操作FunctionRegistry来注册自定义SQL函数。以下是针对你的ExtendSqlServer2012Dialect的具体适配方案：

方案1：重写Dialect的initializeFunctionRegistry方法 #

这是最直接的替代方式，延续原有自定义Dialect的思路：

public class ExtendSqlServer2012Dialect extends SqlServer2012Dialect {
    @Override
    protected void initializeFunctionRegistry(FunctionRegistry registry) {
        // 先调用父类方法初始化默认函数
        super.initializeFunctionRegistry(registry);
        
        // 注册datediffhr：映射到SQL的datediff(hour, 参数1, 参数2)
        registry.registerPattern(
            "datediffhr", 
            "datediff(hour, ?1, ?2)", 
            StandardBasicTypes.INTEGER
        );
        
        // 注册dateaddhr：映射到SQL的dateadd(hour, 参数1, 参数2)
        registry.registerPattern(
            "dateaddhr", 
            "dateadd(hour, ?1, ?2)", 
            StandardBasicTypes.TIMESTAMP
        );
    }
}

复杂场景扩展 #

如果需要自定义参数校验、类型转换等逻辑，可以直接实现SqlFunction接口注册：

registry.registerFunction("datediffhr", new SqlFunction() {
    @Override
    public ReturnType resolveReturnType(Type argumentType, Mapping mapping) {
        return StandardBasicTypes.INTEGER.getReturnedClass();
    }

    @Override
    public boolean hasArguments() {
        return true;
    }

    @Override
    public boolean hasParenthesesIfNoArguments() {
        return true;
    }

    @Override
    public String render(Type argumentType, List<?> arguments, SessionFactoryImplementor sessionFactory) {
        if (arguments.size() != 2) {
            throw new IllegalArgumentException("datediffhr requires exactly 2 arguments");
        }
        return String.format("datediff(hour, %s, %s)", arguments.get(0), arguments.get(1));
    }
});

方案2：不自定义Dialect，通过MetadataBuilder注册函数 #

如果不想维护自定义Dialect，可以在Spring Boot配置类中直接注册函数：

@Configuration
public class HibernateFunctionConfig {
    @Bean
    public LocalContainerEntityManagerFactoryBean entityManagerFactory(DataSource dataSource) {
        LocalContainerEntityManagerFactoryBean em = new LocalContainerEntityManagerFactoryBean();
        em.setDataSource(dataSource);
        em.setPackagesToScan("com.yourproject.entity");
        
        HibernateJpaVendorAdapter vendorAdapter = new HibernateJpaVendorAdapter();
        em.setJpaVendorAdapter(vendorAdapter);
        
        Properties jpaProps = new Properties();
        jpaProps.setProperty("hibernate.dialect", "org.hibernate.dialect.SQLServer2012Dialect");
        em.setJpaProperties(jpaProps);
        
        // 注册自定义SQL函数
        em.setEntityManagerFactoryCallbacks(new EntityManagerFactoryCallback() {
            @Override
            public void postProcessEntityManagerFactory(EntityManagerFactory emf) {
                SessionFactory sessionFactory = emf.unwrap(SessionFactory.class);
                MetadataImplementor metadata = (MetadataImplementor) sessionFactory.getMetadata();
                FunctionRegistry registry = metadata.getSqlFunctionRegistry();
                
                registry.registerPattern("datediffhr", "datediff(hour, ?1, ?2)", StandardBasicTypes.INTEGER);
                registry.registerPattern("dateaddhr", "dateadd(hour, ?1, ?2)", StandardBasicTypes.TIMESTAMP);
            }
        });
        
        return em;
    }
}

配置注意事项 #

• 若使用方案1，需在Spring Boot配置文件中指定自定义Dialect：

  spring.jpa.properties.hibernate.dialect=com.yourproject.ExtendSqlServer2012Dialect
  

• registerPattern方法中的?1、?2对应函数调用时的参数顺序，无需手动拼接参数，Hibernate会自动处理参数绑定。

内容的提问来源于stack exchange，提问作者anil