All interfaces are registered as mybatis mappers even if they are not mappers

[emacarron]

Right now, the mybatis boot starter module takes all the interfaces it founds in a project and registers them as mappers. We should be able to identify if an interface is a mapper or not.

The problem is that mappers are not annotated (the @Mapper annotation does not exist). We did this because we would like to build applications with no mybatis imports at all. So they way you select your mappers when using classic configuraiton like MapperScannerConfigurer or @MapperScan is by:

• specifiying a base package
• specifiying a marker interface
• specifiying a marker annotation

So, my proposal is to use this convention: mappers are supposed to be interfaces held in a */mapper or */mappers package.

For any other configuration, use the @MapperScan annotation that lets you configure everything.

[mallim]

While waiting for this fix, is there anyway to disable the MapperScan from happening? Any example?

[emacarron]

Yes. Add a @MapperScan to your main application class pointing to a dummy interface. That will register a MapperFactoryBean:

@SpringBootApplication
@MapperScan("dummy.package")
public class SampleMybatisApplication implements CommandLineRunner {

or create a MapperFactoryBean explicitly:

@Bean
MapperFactoryBean<Object> createMapper() {
  return new MapperFactoryBean<Object>();
}

If a MapperFactoryBean is detected autoscan is not done.

[mallim]

Thanks for the example, I think this is a good material to put in the docs. If not, people will have to come to this issue and read about this...

Anyway, this is what is working for my case:

@Configuration
@MapperScan("dummy")
public class MybatisConfig {

   @Bean
   public ActualMapper mapper(SqlSessionFactory sqlSessionFactory){
        SqlSessionTemplate sessionTemplate = new SqlSessionTemplate( sqlSessionFactory );
        return sessionTemplate.getMapper(ActualMapper.class);
   }
}

dummy package contains an interface:

public interface DummyMapper {
}

whereby my mybatis-config.xml has some mappers

hope this will help someone ...

[emacarron]

Good to know! BTW, I am curious about this. Do you want to turn off scanning? if so, why?

[mallim]

I am using this way to avoid all interfaces to be registered as mybatis mappers even if they are not mappers. Actually, can we have a setting to turn off the @MapperScan ?

For example:

mybatis:
   scanning: true 

[emacarron]

@mallim But... note that a mapper must be a bean in spring so it can be injected into any other bean. How are you registering your mapper? (or are you using the sqlSessionTemplate?)

[mallim]

Hi @emacarron

I registered all the mappers by using this way:

@Configuration
@MapperScan("dummy") // required since version 1.0.2
public class MybatisConfig {

   @Bean
   public ActualMapper1 mapper(SqlSessionFactory sqlSessionFactory){
        SqlSessionTemplate sessionTemplate = new SqlSessionTemplate( sqlSessionFactory );
        return sessionTemplate.getMapper(ActualMapper1.class);
   }

   @Bean
   public ActualMapper2 mapper(SqlSessionFactory sqlSessionFactory){
        SqlSessionTemplate sessionTemplate = new SqlSessionTemplate( sqlSessionFactory );
        return sessionTemplate.getMapper(ActualMapper2.class);
   }
}

whereby mybatis-config.xml has some mappers

spring-boot-starter works with this pattern since 1.0 👍

[emacarron]

I see, but I would say you have too much boilerplate.

If you set the @MapperScan() with the package name (or pattern) where your mappers are this will work fine and you can remove that two @bean methods.

Can you check that?