How to do spring request parameter conversion

Question

In a Spring 3 based web (portlet) application I have a controller with a method like this:

@RenderMapping
public ModelAn         


        

Answer 1

Spring Portlet MVC 3.0 does not support

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

Visit https://jira.springsource.org/browse/SPR-6817 for more info about this.

However you can add this to your common applicationContext

<bean
    class="org.springframework.web.portlet.mvc.annotation.AnnotationMethodHandlerAdapter">
    <property name="webBindingInitializer">
        <bean
            class="org.springframework.web.bind.support.ConfigurableWebBindingInitializer">
            <property name="conversionService">
                <list>
                    <ref bean="conversionService" />
                </list>
            </property>
        </bean>
    </property>
</bean>

This way you do not need add @InitBinder to every single controller

and of course

<bean id="conversionService"
    class="org.springframework.format.support.FormattingConversionServiceFactoryBean">
    <property name="converters">
        <list>
            <!-- converter implementations here -->
        </list>
    </property>
</bean>

Answer 2

Implement a WebArgumentResolver:

public class MyArgumentResolver implements WebArgumentResolver
{
    @Override
    public Object resolveArgument(MethodParameter methodParameter,
            NativeWebRequest webRequest) throws Exception
    {
        Class<?> paramType = methodParameter.getParameterType();
        if (paramType == MyClass.class)
        {
            String parameterName = methodParameter.getParameterName();
            String stringParameter = webRequest.getParameter(parameterName);
            return convert(stringParameter);
        }
        return UNRESOLVED;
    }
}

And register it in your applicationContext.xml:

<bean class="org.springframework.web.portlet.mvc.annotation.AnnotationMethodHandlerAdapter">
    <property name="customArgumentResolver">
        <bean class="com.dshs.eakte.util.MyArgumentResolver" />
    </property>
</bean>

This works and even has the advantage of allowing parameter conversion that is based on multiple method parameters.

Answer 3

i think you need to use something like

public ModelAndView handleRenderRequest(...,@ModelAttribute("myObject") MyClass myObject)

Answer 4

You are correct that Converter (and ConverterFactory) are the successors to property editors. Your problem may be that you are not accepting the appropriate type as a parameter to your converter, but that's hard to say without seeing the converter code. If you are expecting Long or Integer you may actually be getting a String from Spring and need to perform that key conversion yourself first.

As for configuration, I believe you need to list all of your converters in the bean configuration in your xml. If you annotate your converter implementation with @Component you might be able to reference it by the bean name instead of the fully qualified path, but I have only tried that for a ConverterFactory, not a Converter.

Finally, on specific converters, it looks like you may be able to configure the conversion service at the controller level (see Javi's answer on Setting up a mixed configuration for annotation-based Spring MVC controllers ) and then you could just place that method (and others that require that controller) into a controller that uses a secondary conversion service which you ought to be able to inject by name with the @Resource annotation.

Answer 5

To achieve something similar to what you're doing, I found this blog entry useful.