Home » Enterprise Java » spring » MVC » Spring MVC interceptor example

About Byron Kiourtzoglou

Byron Kiourtzoglou
Byron is a master software engineer working in the IT and Telecom domains. He is an applications developer in a wide variety of applications/services. He is currently acting as the team leader and technical architect for a proprietary service creation and integration platform for both the IT and Telecom industries in addition to a in-house big data real-time analytics solution. He is always fascinated by SOA, middleware services and mobile development. Byron is co-founder and Executive Editor at Java Code Geeks.

Spring MVC interceptor example

The demonstration code shows you how to modify the incoming HttpServletRequest object before it reaches your controller. This does nothing more than add a simple string to the request.

public class RequestInitializeInterceptor extends HandlerInterceptorAdapter {
 
  // Obtain a suitable logger.
  private static Log logger = LogFactory

.getLog(RequestInitializeInterceptor.class);
 
  /**
   * In this case intercept the request BEFORE it reaches the controller
   */
  @Override
  public boolean preHandle(HttpServletRequest request,

HttpServletResponse response, Object handler) throws Exception {
    try {
 

logger.info("Intercepting: " + request.getRequestURI());
 

// Do some changes to the incoming request object

updateRequest(request);
 

return true;
    } catch (SystemException e) {

logger.info("request update failed");

return false;
    }
  }
 
  /**
   * The data added to the request would most likely come from a database
   */
  private void updateRequest(HttpServletRequest request) {
 
    logger.info("Updating request object");
    request.setAttribute("commonData",

  "This string is required in every request");
  }
 
  /** This could be any exception */
  private class SystemException extends RuntimeException {
 
    private static final long serialVersionUID = 1L;
    // Blank
  }
}

The next step in implementing an interceptor is, as always, to add something to the Spring XML config file:

<!-- Configures Handler Interceptors --> 
<mvc:interceptors>  
 <!-- This bit of XML will intercept all URLs - which is what you want in a web app -->
 <bean class="marin.interceptor.RequestInitializeInterceptor" />
 
 <!-- This bit of XML will apply certain URLs to certain interceptors -->
 <!-- 
 <mvc:interceptor>
  <mvc:mapping path="/gb/shop/**"/>
  <bean class="marin.interceptor.RequestInitializeInterceptor" />
 </mvc:interceptor>
  -->
</mvc:interceptors>

The XML above demonstrates an either/or choice of adding an interceptor to all request URLs, or if you look at the commented out section, adding an interceptor to specific request URLs, allowing you to choose which URLs are connected to your interceptor class.

Related Article:

Reference: Using Spring Interceptors in your MVC Webapp from our JCG partner Roger Hughes at the Captain Debug’s blog

Do you want to know how to develop your skillset to become a Java Rockstar?

Subscribe to our newsletter to start Rocking right now!

To get you started we give you our best selling eBooks for FREE!

1. JPA Mini Book

2. JVM Troubleshooting Guide

3. JUnit Tutorial for Unit Testing

4. Java Annotations Tutorial

5. Java Interview Questions

6. Spring Interview Questions

7. Android UI Design

and many more ....

 

Do you want to know how to develop your skillset and become a ...

Subscribe to our newsletter to start Rocking right now!

To get you started we give you our best selling eBooks for FREE!
Get ready to Rock!
To download the books, please verify your email address by following the instructions found on the email we just sent you.

THANK YOU!

Close