I am getting a java.lang.NullPointerException in BlogValidator  when I try to creat a blog.

the exception happens  in the code line:

Blog oldBlog = blogDao.getBlogByTitle( title );

it even didn't get to the blogDaoImp.getBlogByTitle() level,  seems the system couldn't successfully assign a blogDao for it?

The log is attached below.  Please help!  Thanks a lot.

I think so.   In the BlogValidator class,  I have 

protected BlogDao blogDao;

public void setBlogDao (BlogDao blogDao){}

and in spring-servlet.xml, I defined

<bean id="blogValidator"
        class="csns.spring.validator.BlogValidator">
        <property name="blogDao" ref="blogDao" />
    </bean>

anywhere else I need to "wire" the blogDao to the Validator?

Thanks!