Custom DataBinder in Spring 3.0

[garyfisher]

Hello,

I'm migrating our project to Spring 3.0. Most of the issues is resolved but one of them not.

We used to create our own custom DataBinder in a AnnotationMethodHandlerAdapter subclass. We used to override the createBinder() method and created our own DataBinder implementation there.

How to achieve the same in Spring 3.0. The createBinder() method disappeared.

Thank you.

[garyfisher]

Nobody with the same problem?

[MartyJones]

You can use the following annotation declaration:

@InitBinder    
public void initBinder(WebDataBinder binder) {
    ...define custom editors here.
}

[garyfisher]

You can use the following annotation declaration:

@InitBinder    
public void initBinder(WebDataBinder binder) {
    ...define custom editors here.
}

You don't understand my needs. In Spring 2.5 we did something like this:

@InitBinder    
public void initBinder(MyDataBinder binder) {
    ...define custom editors here.
}

And we were able to override createBinder() method in a Spring MVC class to produce our custom DataBinder. And it seems this is not possible in Spring 3.0.0.RC3

[MartyJones]

I understand your question now. Spring 3 has incorporated a ConversionService that does Type Conversion for you (at least the common conversions).

They do state that if a ConversionService is not registered then it will fall back to the PropertyEditor method. The problem I have is that if you specifiy <mvc:annotation-driven /> then it by default loads the default conversion service so Property editor support does not work!

Take a look at this link to learn how to set it up and how to add custom type converters:

http://static.springsource.org/sprin...l/ch05s05.html

[garyfisher]

I understand your question now. Spring 3 has incorporated a ConversionService that does Type Conversion for you (at least the common conversions).

They do state that if a ConversionService is not registered then it will fall back to the PropertyEditor method. The problem I have is that if you specifiy <mvc:annotation-driven /> then it by default loads the default conversion service so Property editor support does not work!

Take a look at this link to learn how to set it up and how to add custom type converters:

http://static.springsource.org/sprin...l/ch05s05.html

After reading the docs I still don't understand the problem. Even if I use ConversionService I still need to use @InitBinder to configure controller specific bindings.

So how does ConversionService replace DataBinder? Especially in @InitBinder methods?

Thanks.

[MartyJones]

Gary, You do NOT need to use initBinder if you are using the ConversionService. I just stood up a Web app that is using the Conversion service and I don't use @InitBinding.

There are two basic conversion service factory beans.

1. ConversionServiceFactoryBean - This class sets up default converters for converting strings to basic objects. This class allows you to specify custom object converters. For example:

<bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean" >
    <property name="converters">
        <list>
            <bean class="com.foo.MyClassConverter"/>
        </list>
    </property>
</bean>

2. FormattingConversionServiceFactoryBean - This class sets up basic formatters for doing date and number conversions as well as setup default converters for converting strings to objects.

I extended the FormattingConversionServiceFactoryBean and added a setConverters method so that I can add my custom converters through the configuration.

So to answer your question. You specify your custom type converters within the conversionService bean configuration setup like the code snippet above. The conversion service will handle the rest for you.

Let me know if this did not answer your question.

Marty

[garyfisher]

Gary, You do NOT need to use initBinder if you are using the ConversionService. I just stood up a Web app that is using the Conversion service and I don't use @InitBinding.

There are two basic conversion service factory beans.

1. ConversionServiceFactoryBean - This class sets up default converters for converting strings to basic objects. This class allows you to specify custom object converters. For example:

<bean id="conversionService" class="org.springframework.context.support.ConversionServiceFactoryBean" >
    <property name="converters">
        <list>
            <bean class="com.foo.MyClassConverter"/>
        </list>
    </property>
</bean>

2. FormattingConversionServiceFactoryBean - This class sets up basic formatters for doing date and number conversions as well as setup default converters for converting strings to objects.

I extended the FormattingConversionServiceFactoryBean and added a setConverters method so that I can add my custom converters through the configuration.

So to answer your question. You specify your custom type converters within the conversionService bean configuration setup like the code snippet above. The conversion service will handle the rest for you.

Let me know if this did not answer your question.

Marty

I understand how ConversionService works. I can even imagine that I need less @InitBinder methods, but I don't believe that I will stop use them. There are still needs to specify custom bindings for most of the forms in our application.

Anyway, this is not point of my issue! Have a look at DataBinder and WebDataBinder classes. There is a lot of methods designed to be overridden. For example getEmptyValue(), getAllowedFields(), etc. So you are allowed and encouraged to implement your own DataBinder if you need. And it was possible until Spring 3.0. So this issue hurts backwards compatibility too.

I'm creating JIRA issue for this.

[garyfisher]

JIRA issue SPR-6534

http://jira.springframework.org/browse/SPR-6534

[tudor.stanciu]

Any ideea how i can do this (namely replace the WebDataBinder) for an annotated controller (@Controller) ?
Thanks,
Tudor