Spring Converter重用

Question

I'm trying to use Spring Custom Converters to convert from my Persistence Objects to Json Objects (for UI layer).

DBO's

class Adbo{
  Bdbo b = new Bdbo();
}
class Bdbo{}

UI POJOS

class APoj{
  BPoj b = new Poj();
}
class BPoj{}

These are my Converters

class APojToADbo implements Converter<ADbo, APoj>{
    @Override
    public APoj convert(ADbo source) {
        //..code to convert
        //..also includes conversion from BDbo to BPoj
    }
}
class ADboToAPoj implements Converter<APoj, ADbo>{
    @Override
    public ADbo convert(APoj source) {
        //..code to convert
        //..also includes conversion from BPoj to BDbo
    }
}
class BPojToBDbo implements Converter<BDbo, BPoj>{
    @Override
    public BPoj convert(BDbo source) {
        //..code to convert
    }
}
class BDboToBPoj implements Converter<BPoj, BDbo>{
    @Override
    public BDbo convert(BPoj source) {
        //..code to convert
    }
}

I register my converters into the ConversionService with this

@Bean
public ConversionServiceFactoryBean getConversionService(){
  ConversionServiceFactoryBean c = new ConversionServiceFactoryBean();
  Set<Converter> converters = new HashSet<>();
  converters.add(aPojToADbo);
  converters.add(aDboToAPoj);
  converters.add(bPojToBDbo);
  converters.add(bDboToBPoj);
  c.setConverters(converters);
  return c;
}

Now I'm trying to refactor so that I can avoid writing this

//..also includes conversion from BDbo to BPoj
//..also includes conversion from BPoj to BDbo

in 2 places , So I did this in APojToADbo

@Autowired
protected ConversionService conversionServ;

and If I do the above, I'm getting the following exception

Caused by: org.springframework.beans.factory.NoSuchBeanDefinitionException: No qualifying bean of type [org.springframework.core.convert.ConversionService] found for dependency: expected at least 1 bean which qualifies as autowire candidate for this dependency. Dependency annotations: {@org.springframework.beans.factory.annotation.Autowired(required=true)}

Because IoC is not completed yet on the ConversionService bean. Circular Dependency!

There was this nice article on how to avoid Circular Dependency, but I want to know if Spring provides any cleaner/elegant way to do this inside converters

Answer 1

I would suggest you to return the ConversionService and set the afterPropertiesSet

  @Bean 
    public ConversionService getConversionService() { 
     ConversionServiceFactoryBean bean = new ConversionServiceFactoryBean();
             bean.setConverters( getConverters() );

    bean.afterPropertiesSet();

    ConversionService object = bean.getObject();
     return object;
             } 

Answer 2

I ended up doing this to my converters:

class BaseConverter {
   @Autowired
   ApplicationContext alpCtx;
   public ConversionService getConversaionService(){
      alpCtx.getBean("conversionService");
   }
}
class APojToADbo extends BaseConverter implements Converter<>{
   convert(){
      getConversaionService() //return lookup from alpCtx and return from Baseclass
   }
}