If you want to integrate DWR 3.x with Spring you can follow my previous posts:

1. I am using DWR 2.0.x, Spring 2.x, and Spring MVC
2. I am using DWR 2.0.x, Spring 2.x, but I am not using Spring MVC

However, you will need to make the following changes.

Spring 2.5 or greater is Required

You must upgrade to Spring 2.5 or higher.

Update you Spring Application Context

Update your Spring Application Context:

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:dwr="http://www.directwebremoting.org/schema/spring-dwr"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="http://www.springframework.org/schema/beans

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd

http://www.directwebremoting.org/schema/spring-dwr

         http://www.directwebremoting.org/schema/spring-dwr-3.0.xsd">