Spring MVC Interceptor HandlerInterceptorAdapter, HandlerInterceptor Example

Filed Under: Spring

Spring Interceptor are used to intercept client requests and process them. Sometimes we want to intercept the HTTP Request and do some processing before handing it over to the controller handler methods. That’s where Spring MVC Interceptor come handy.

Spring Interceptor

spring interceptor, spring mvc interceptor, HandlerInterceptorAdapter, HandlerInterceptor

Just like we have Struts2 Interceptors, we can create our own Spring interceptor by either implementing org.springframework.web.servlet.HandlerInterceptor interface or by overriding abstract class org.springframework.web.servlet.handler.HandlerInterceptorAdapter that provides the base implementation of HandlerInterceptor interface.

Spring Interceptor – HandlerInterceptor

Spring HandlerInterceptor declares three methods based on where we want to intercept the HTTP request.

  1. boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler): This method is used to intercept the request before it’s handed over to the handler method. This method should return ‘true’ to let Spring know to process the request through another spring interceptor or to send it to handler method if there are no further spring interceptors.

    If this method returns ‘false’ Spring framework assumes that request has been handled by the spring interceptor itself and no further processing is needed. We should use response object to send response to the client request in this case.

    Object handler is the chosen handler object to handle the request. This method can throw Exception also, in that case Spring MVC Exception Handling should be useful to send error page as response.

  2. void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView): This HandlerInterceptor interceptor method is called when HandlerAdapter has invoked the handler but DispatcherServlet is yet to render the view. This method can be used to add additional attribute to the ModelAndView object to be used in the view pages. We can use this spring interceptor method to determine the time taken by handler method to process the client request.
  3. void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex): This is a HandlerInterceptor callback method that is called once the handler is executed and view is rendered.

If there are multiple spring interceptors configured, preHandle() method is executed in the order of configuration whereas postHandle() and afterCompletion() methods are invoked in the reverse order.

Let’s create a simple Spring MVC application where we will configure an Spring Interceptor to log timings of controller handler method.

Our final Spring Interceptor example project will look like below image, we will look into the components that we are interested in.

Spring MVC Interceptor, Spring Interceptor example, Spring interceptor

Spring Interceptor – Controller Class


package com.journaldev.spring;

import java.text.DateFormat;
import java.util.Date;
import java.util.Locale;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.stereotype.Controller;
import org.springframework.ui.Model;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

/**
 * Handles requests for the application home page.
 */
@Controller
public class HomeController {
	
	private static final Logger logger = LoggerFactory.getLogger(HomeController.class);
	
	@RequestMapping(value = "/home", method = RequestMethod.GET)
	public String home(Locale locale, Model model) {
		logger.info("Welcome home! The client locale is {}.", locale);
		//adding some time lag to check interceptor execution
		try {
			Thread.sleep(1000);
		} catch (InterruptedException e) {
			e.printStackTrace();
		}
		Date date = new Date();
		DateFormat dateFormat = DateFormat.getDateTimeInstance(DateFormat.LONG, DateFormat.LONG, locale);
		
		String formattedDate = dateFormat.format(date);
		
		model.addAttribute("serverTime", formattedDate );
		logger.info("Before returning view page");
		return "home";
	}
	
}

I am just adding some processing time in the execution of the handler method to check our spring interceptor methods in action.

Spring MVC Interceptor – HandlerInterceptorAdapter Implementation

For simplicity, I am extending abstract class HandlerInterceptorAdapter. HandlerInterceptorAdapter is abstract adapter class for the HandlerInterceptor interface, for simplified implementation of pre-only/post-only interceptors.


package com.journaldev.spring;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.handler.HandlerInterceptorAdapter;

public class RequestProcessingTimeInterceptor extends HandlerInterceptorAdapter {

	private static final Logger logger = LoggerFactory
			.getLogger(RequestProcessingTimeInterceptor.class);

	@Override
	public boolean preHandle(HttpServletRequest request,
			HttpServletResponse response, Object handler) throws Exception {
		long startTime = System.currentTimeMillis();
		logger.info("Request URL::" + request.getRequestURL().toString()
				+ ":: Start Time=" + System.currentTimeMillis());
		request.setAttribute("startTime", startTime);
		//if returned false, we need to make sure 'response' is sent
		return true;
	}

	@Override
	public void postHandle(HttpServletRequest request,
			HttpServletResponse response, Object handler,
			ModelAndView modelAndView) throws Exception {
		System.out.println("Request URL::" + request.getRequestURL().toString()
				+ " Sent to Handler :: Current Time=" + System.currentTimeMillis());
		//we can add attributes in the modelAndView and use that in the view page
	}

	@Override
	public void afterCompletion(HttpServletRequest request,
			HttpServletResponse response, Object handler, Exception ex)
			throws Exception {
		long startTime = (Long) request.getAttribute("startTime");
		logger.info("Request URL::" + request.getRequestURL().toString()
				+ ":: End Time=" + System.currentTimeMillis());
		logger.info("Request URL::" + request.getRequestURL().toString()
				+ ":: Time Taken=" + (System.currentTimeMillis() - startTime));
	}

}

The logic is really simple, I am just logging the timings of handler method execution and total time taken in processing the request including rendering view page.

Spring MVC Interceptor Configuration

We have to wire the spring interceptor to the requests, we can use mvc:interceptors element to wire all the interceptors. We can also provide URI pattern to match before including the spring interceptor for the request through mapping element.

Our final spring bean configuration file (spring.xml) looks like below.


<?xml version="1.0" encoding="UTF-8"?>
<beans:beans xmlns="http://www.springframework.org/schema/mvc"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:beans="http://www.springframework.org/schema/beans"
	xmlns:context="http://www.springframework.org/schema/context"
	xsi:schemaLocation="http://www.springframework.org/schema/mvc http://www.springframework.org/schema/mvc/spring-mvc.xsd
		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
		http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

	<!-- DispatcherServlet Context: defines this servlet's request-processing 
		infrastructure -->

	<!-- Enables the Spring MVC @Controller programming model -->
	<annotation-driven />

	<!-- Handles HTTP GET requests for /resources/** by efficiently serving 
		up static resources in the ${webappRoot}/resources directory -->
	<resources mapping="/resources/**" location="/resources/" />

	<!-- Resolves views selected for rendering by @Controllers to .jsp resources 
		in the /WEB-INF/views directory -->
	<beans:bean
		class="org.springframework.web.servlet.view.InternalResourceViewResolver">
		<beans:property name="prefix" value="/WEB-INF/views/" />
		<beans:property name="suffix" value=".jsp" />
	</beans:bean>

	<!-- Configuring interceptors based on URI -->
	<interceptors>
		<interceptor>
			<mapping path="/home" />
			<beans:bean class="com.journaldev.spring.RequestProcessingTimeInterceptor"></beans:bean>
		</interceptor>
	</interceptors>

	<context:component-scan base-package="com.journaldev.spring" />

</beans:beans>

I will not explain all other components of the web application, because we are not interested in them and they don’t have any specific spring interceptor related configuration.

Spring MVC Interceptor Application Testing

Just deploy the application in servlet container and invoke the home controller, you will see logger output something like below.


INFO : com.journaldev.spring.RequestProcessingTimeInterceptor - Request URL::http://localhost:9090/SpringInterceptors/home:: Start Time=1396906442086
INFO : com.journaldev.spring.HomeController - Welcome home! The client locale is en_US.
INFO : com.journaldev.spring.HomeController - Before returning view page
Request URL::http://localhost:9090/SpringInterceptors/home Sent to Handler :: Current Time=1396906443098
INFO : com.journaldev.spring.RequestProcessingTimeInterceptor - Request URL::http://localhost:9090/SpringInterceptors/home:: End Time=1396906443171
INFO : com.journaldev.spring.RequestProcessingTimeInterceptor - Request URL::http://localhost:9090/SpringInterceptors/home:: Time Taken=1085

The output confirms that the spring interceptor methods are executed in the order defined.

That’s all for using spring interceptors, you can download the Spring Interceptor example project from below link and try to have multiple interceptors and check by different order of configuration.

Comments

  1. Sanjoy says:

    Hi Pankaj,
    I have an application which track sessions through cookies. When I check rootInterceptor class, I found cookies are null in httpServletRequest, but avilable in httpServletResponse parameter and having value of jsessionid. Not able to understand where it got set.
    Request your help here.

  2. mohammed says:

    Hi Pankaj,

    in preHand;le() method , I am checking max inactive Interval time, if it exceeds I am trying to redirect it to login page like
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
    long startTime = System.currentTimeMillis();
    logger.info(“Request URL::” + request.getRequestURL().toString() + “:: Start Time=” +System.currentTimeMillis());
    request.setAttribute(“startTime”, startTime);
    request.logout();
    response.sendRedirect(“my full url”) ;
    return false;
    }
    its not redirecting…pls help me

  3. Ashwini Waghmode says:

    I have classes for systemException and businessException as well as constant file in which success or error messages are stored.But,i don’t know how to use.please,tell me.

    1. Akash says:

      Hi.. do you know how to return false in preHandle()?

  4. Ran says:

    How to pass an object from Interceptor to controller?

  5. Robert says:

    Hello Pankaj,

    Thank you for the clear example on spring interceptors. Really appreciate it. My question is on Spring itself really and its enthusiasm for adding a plethora of additional dependencies that potentially clogs up the project over time.

    I checked the pom file in your project example and there is a lot of “stuff” in there. This is not critique to you, just a question. 🙂

    Do you know/have available a bare minimal amount of dependencies that are needed or is this listed dependencies in the project optimal ?

    BR, Robert

    1. Pankaj says:

      Hi Robert,

      There has been a lot of changes in Spring, if you are using latest versions then you can remove many of the logging related dependencies. You can always run mvn dependency:tree to find transitive dependencies or unused dependencies and remove them from pom.xml file. This will keep your pom.xml file small and clean.

  6. Rajat Mishra says:

    You are awesome. Never stop writing such awesome blogs.

  7. akash says:

    how to apply logging interceptor for all methods what should i do.
    like ,for create we use following

    if i want do this fr all what should i do

  8. Akhil says:

    How to use @Autowired service in handler….If i am using then null pointer exception will occur

    1. Tejas says:

      It is nothing but creating object .As suppose I have written service in Class *ServiceImpl.java . I will write autowired as

      class {

      @Autowired
      *ServiceImpl ,

      and use reference everywhere
      }

  9. lastspring says:

    How to modify the respone ?

  10. Rita says:

    Problem : I am calling spring controller using curl request.
    As Input I am passing a json with request to controller.

    Now I just want to fetch that json inside spring interceptor .But it is not working for me.

    Enumeration en=request.getParameterNames();
    System.out.println(Collections.list(en).size());

    It is giving zero size.

    Please take a look.

    1. Pankaj says:

      Could you please post your curl command? What is the HTTP method you are using, it should be POST in your case, not GET as in this example.

  11. Pupsick says:

    The presence of so many logging dependencies and exclusions is amazing. Even such a tiny app. required … 7!!! Artifacts. Surely that was not what logging was meant to be. But this is what is wrong with open source in general.

    1. saljuama says:

      Really? this is what you get out of an Interceptor tutorial? some rant about logging dependencies? that in fact are generated automatically when creating a spring project using eclipse (STS) the old fashion way, which is tailored to give easy time for developers. This smells like open source hater to me.

    2. Pankaj says:

      You can actually clean them up and just use what you need, I am bit lazy to do that for my example code.

  12. Evgeny says:

    Thanks !
    Simple and intuitive !

    1. Pankaj says:

      You are welcome friend.

  13. Ram says:

    Hi,
    when I am getting the parameter value from request, its a null value. so how should I get the parameter value in interceptor.

    1. Pankaj says:

      Please provide some code snippet, what is your HTTP method? How you are passing request parameters?

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