Java Config equivalent for conversionService / FormattingConversionServiceFactoryBean

Question

I have an entity that contains another entity, as follows:

public class Order {

    @Id
    private int id;

    @NotNull
    private Date requestDate;

    @NotNull
    @ManyToOne(cascade=CascadeType.ALL)
    @JoinColumn(name="order_type_id")
    private OrderType orderType;
}

public class OrderType {

    @Id
    private int id;

    @NotNull
    private String name;
}

I have a Spring MVC form where a user can submit a new order; the fields they have to fill in are the Request Date and select an Order Type (which is a drop-down).

I am using Spring Validation to validate the form input which fails as it is trying to convert an orderType.id to an OrderType.

I have written a custom converter to convert an orderType.id into an OrderType object:

public class OrderTypeConverter implements Converter<String, OrderType> {

    @Autowired
    OrderTypeService orderTypeService;

    public OrderType convert(String orderTypeId) {

        return orderTypeService.getOrderType(orderTypeId);
    }
}

My problem is I don't know how to register this converter with Spring using java config. The XML equivalent I've found (from Dropdown value binding in Spring MVC) is:

<mvc:annotation-driven conversion-service="conversionService"/>

<bean id="conversionService"
    class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
    <property name="converters">
       <list>
          <bean class="OrderTypeConverter"/>
       </list>
    </property>
</bean>

From searching the web I can't seem to find a java config equivalent - can someone please help me out?

UPDATE

I have added the OrderTypeConvertor to the WebMvcConfigurerAdapter as follows:

public class MvcConfig extends WebMvcConfigurerAdapter{

    ...

    @Override
    public void addFormatters(FormatterRegistry registry) {
        registry.addConverter(new OrderTypeConvertor());
    }
}

However I get a null pointer exception in OrderTypeConvertor as orderTypeService is null, presumably because it is autowired and I've used the new keyword above. Some further help would be appreciated.

Answer 1

All you need to do in your case is:

@Configuration
public class MvcConfig extends WebMvcConfigurerAdapter{

    @Autowired
    private OrderTypeConvertor orderTypeConvertor;

    ...

    @Override
    public void addFormatters(FormatterRegistry registry) {
        registry.addConverter(orderTypeConvertor);
    }
}