Enabling Spring context to HttpServlet using SpringBeanAutowiringSupport

I recently had this requirement where i had to enable Spring context to an HttpSevlet.

So this is how is started with

web.xml

<context-param>
        <param-name>contextConfigLocation</param-name>
        <param-value>
         classpath*:/spring-bootstrap.xml
   classpath*:/spring-service.xml
        </param-value>
    </context-param> 

   <listener>
        <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
    </listener> 

    
    <servlet>
        <servlet-name>proxy</servlet-name>
        <servlet-class>com.proxy.servlet.HttpProxyServlet</servlet-class>
       <!--  <init-param>
            <param-name>contextConfigLocation</param-name>
            <param-value></param-value>
        </init-param> -->
         
         <load-on-startup>1</load-on-startup>
    </servlet>
 
    <servlet-mapping>
        <servlet-name>proxy</servlet-name>
        <url-pattern>/api/proxy/*</url-pattern>
    </servlet-mapping>

spring-bootstrap.xml

 <beans profile="custom">
        <!-- Can't use context:property-placeholder until Spring bug SPR-7765 is addressed -->
         <bean class="org.springframework.context.support.PropertySourcesPlaceholderConfigurer" 
              p:location="file:#{systemProperties['app.conf']}" /> 
        <!-- <context:property-placeholder location="classpath:/app.conf" />   -->    
    </beans>

Note i am using spring profile to load properties to the application context

Now, in my ProxyServlet , i want to load values from the properties , so this is what I did

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@Value("${REALM_ID:}") private String ENV_REALM_ID; @Value("${service_base_url:}") private String ENV_SERVICE_BASE_URL;

But as it turns out that the servlet did not load the values. By default the spring dependencies are not injected. So to do that i had to add the following

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@Override public void init(ServletConfig servletConfig) throws ServletException { super.init(servletConfig); SpringBeanAutowiringSupport.processInjectionBasedOnCurrentContext(this); }

Another way of doing this is

1	applicationContext = WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());

The following post was useful in solving the prob

how-to-mage-java-servlet-managed-or-di-in-spring