升级Micronaut到4.3.1启动报错：SessionFactory Bean加载失败

将项目升级至Micronaut 4.3.1后，启动服务器时出现如下错误：

ERROR io.micronaut.runtime.Micronaut - Error starting Micronaut server: Bean definition [org.hibernate.SessionFactory] could not be loaded: Error instantiating bean of type  [io.micronaut.configuration.hibernate.jpa.conf.sessionfactory.configure.internal.ValidatorFactoryConfigurer]

Message: Multiple possible bean candidates found: [DefaultConstraintValidatorFactory, DefaultInternalConstraintValidatorFactory]
Path Taken: SessionFactoryPerDataSourceFactory.buildHibernateSessionFactoryBuilder(SessionFactoryBuilder sessionFactoryBuilder) --> new SessionFactoryPerDataSourceFactory(Environment environment,[List configures],StandardServiceRegistryBuilderCreator serviceRegistryBuilderSupplier,List standardServiceRegistryBuilderConfigurers,JpaConfiguration jpaConfiguration,ApplicationContext applicationContext,Integrator integrator) --> new ValidatorFactoryConfigurer([ValidatorFactory validatorFactory])
io.micronaut.context.exceptions.BeanInstantiationException: Bean definition [org.hibernate.SessionFactory] could not be loaded: Error instantiating bean of type  [io.micronaut.configuration.hibernate.jpa.conf.sessionfactory.configure.internal.ValidatorFactoryConfigurer]

使用Micronaut Data Hibernate JPA，原本预期应用能像4.2.X版本一样正常运行，这似乎是Hibernate配置问题。

解决方案 #

• 给其中一个ValidatorFactory实现类添加@Primary注解，让Micronaut容器明确优先选择该Bean，示例代码：

  @Bean
  @Primary
  public ValidatorFactory defaultValidatorFactory() {
      return Validation.byDefaultProvider().configure().buildValidatorFactory();
  }
  

• 检查项目依赖，排除重复引入的Hibernate Validator相关模块。比如Maven环境下，在micronaut-data-hibernate-jpa依赖中做排除：

  <dependency>
      <groupId>io.micronaut.data</groupId>
      <artifactId>micronaut-data-hibernate-jpa</artifactId>
      <exclusions>
          <exclusion>
              <groupId>org.hibernate.validator</groupId>
              <artifactId>hibernate-validator</artifactId>
          </exclusion>
      </exclusions>
  </dependency>
  

• 自定义ValidatorFactoryConfigurer Bean，手动注入指定的ValidatorFactory，绕开自动注入的候选冲突：

  @Bean
  public ValidatorFactoryConfigurer customValidatorFactoryConfigurer(ValidatorFactory validatorFactory) {
      return new ValidatorFactoryConfigurer(validatorFactory);
  }
  

• 若上述方法暂不生效，可临时回退到Micronaut 4.2.X版本，等待官方发布该兼容性问题的修复补丁。

内容的提问来源于stack exchange，提问作者Kareem Elzayat