Spring - How to make a bean object available via @Autowired at any layer

Hi,

Recently in a project I faced a situation where there was a need that one java object needs to be accessed by different layers like Controller, Biz, DAO layers etc. 

PROBLEM TAKEN

I had a UserInfo object that contains the User information who has logged into the system and his authorities.  You can think it as ThreadLocal object containing user information and his authorities.  And I want to access it in most of the other spring component classes.

TECHNOLOGY STACK

•       Spring
•       Hibernate
•       Tomcat
•       Maven
•       jQuery

SOLUTION APPROACH

To solve this problem I made one CustomSuccessHandler by extending org.springframework.security.web.authentication.SavedRequestAwareAuthenticationSuccessHandler.

This handler populates the User object in UserInfo class after successful authentication.  Below is the structure of UserInfo class.

            UserInfo.java

@Component

public class UserInfo

{

    private User ctxUser;

    ....

    /**

     * @return the ctxUser

     */

    public User getCtxUser()

    {

        return ctxUser;

    }

    /**

     * @param ctxUser

     *            the ctxUser to set

     */

    public void setCtxUser(User ctxUser)

    {

        this.ctxUser = ctxUser;

        populateGroupsAuth();

    }

    ....

    ....

}

You can place additional variables if required.  Here User is my own pojo class.  It has some fields and getters/setters.

Now to support

    @Autowired

    User ctxUser;

In any java file within Spring Context I include below entries in applicationContext.xml or you can do that in any of your context representing xml file.         

First way:

    <bean id="userInfo" class="UserInfo"

        scope="session">

        <aop:scoped-proxy />

    </bean>

    <bean

        class="org.springframework.web.context.support.ServletContextAttributeExporter"

        p:attributes-ref="servletContextAttributesMap">

    </bean>

    <util:map id="servletContextAttributesMap">

        <entry key="appCtx">

            <ref bean="userInfo" />

        </entry>

    </util:map>

Second way:

Assuming all your views are going via some controller that is intercepted by spring’s InternalResourceViewResolver

    <bean id="viewResolver"

        class="org.springframework.web.servlet.view.InternalResourceViewResolver">

        <property name="prefix">

            <value>/pages/</value>

        </property>

        <property name="suffix">

            <value>.jsp</value>

        </property>

        <property name="exposeContextBeansAsAttributes" value="true"/>

        <property name="exposedContextBeanNames">

            <list>

                <value>userInfo</value>

            </list>

        </property>

    </bean>

                In this case you can now access UserInfo bean at class level and use it.

Third way:

To allow a bean object to be available in your request object below is the configuration for the same class

    <bean id='userInfo' class='UserInfo' />

    <bean scope="request" factory-bean="userInfo"

        factory-method="getCtxUser">

        <aop:scoped-proxy />

    </bean>

Please do let me know if you need more information.

Thanks

Shailendra