Rest Custom HTTP Message Converter Spring Boot 1.2.3

Question

I want to create a custom of HttpMessageConverter using Rest, Json, Spring Boot 1.2.3 and Spring 4, However my custom HTTPMessageConverter its' never called.

I have preformed the following steps :

1: Created a class that extends AbstractHttpMessageConverter

@Component
public class ProductConverter extends AbstractHttpMessageConverter<Employee>   {

public ProductConverter() {
     super(new MediaType("application", "json", Charset.forName("UTF-8")));     
     System.out.println("Created ");
}

@Override
protected boolean supports(Class<?> clazz) {
    return false;
}

@Override
protected Employee readInternal(Class<? extends Employee> clazz,
        HttpInputMessage inputMessage) throws IOException,
        HttpMessageNotReadableException {
    InputStream inputStream =  inputMessage.getBody();
    System.out.println("Test******");
    return null;
}

@Override
protected void writeInternal(Employee t,
        HttpOutputMessage outputMessage) throws IOException,
        HttpMessageNotWritableException {
    // TODO Auto-generated method stu   
}

}

2: I create a configuration class to register HTTPMessageConverters

@Configuration
public class WebMvcConfig extends WebMvcConfigurerAdapter{  
   @Override
   public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
     System.out.println("Configure Message Converters");
     converters.add(new ProductConverter());
     super.configureMessageConverters(converters);
     //super.extendMessageConverters(converters);
    }
 }

3: The rest class method

@RequestMapping(value="/{categoryId}" ,method=RequestMethod.POST, consumes="application/json")
@PreAuthorize("permitAll")
public ResponseEntity<ProductEntity>  saveProduct(@RequestBody Employee  employee , @PathVariable Long categoryId) {

    logger.log(Level.INFO, "Category Id: {0}" , categoryId);

    ResponseEntity<ProductEntity> responseEntity =
            new ResponseEntity<ProductEntity>(HttpStatus.OK);
    return responseEntity;
}

My Custom HTTPMessageCoverter it's created but is never called ? Is there a configuration or step I'm missing ? any input or advice is appreciated.

---

After overriding the (AbstractHttpMessageConverter) class methods, I found out there's two annotations for achieving polymorphism @JsonTypeInfo and @JsonSubTypes. For anyone who wants achieve polymorphism can use these two annotations.

Answer 1

I believe you want to configure these message converters using the configureMessageConverters method in a configuration class that extends WebMvcConfigurerAdapter. I've done this myself with a converter for CSV content. I've included that code below. This link shows an example as well. This link may also be helpful. It seems like with Spring configuration it is not always clear on the best place to configure things. :) Let me know if this helps.

@Configuration
public class ApplicationWebConfiguration extends WebMvcConfigurerAdapter {
     @Override
    public void configureMessageConverters(List<HttpMessageConverter<?>> converters) {
        super.configureMessageConverters(converters);
        converters.add(new CsvMessageConverter());
    }
}

You will also need top modify your supports() method to return true for classes supported by the converter. See the Spring doc for AbstractHttpMessageConverter supports method.