Thursday, October 20, 2016

RESTEasy Spring 4 integration

Recently when I was going through the RESTEasy documentation to find out the proper way to integrate it with Spring. There are several ways to do it. This is the first post in this series which will cover the ways to integrate RESTEasy with Spring.

We will start with the one which is mentioned in the RESTEasy documentation. We will be using Maven for dependency management in our project. First of all, add the RESTEasy dependency in your project,


  org.jboss.resteasy
  resteasy-spring
  whatever version you are using


Above code will add resteasy dependencies in your project. Next step is to define RESTEasy configuration in your web.xml.


 Archetype Created Web Application
 
  
   org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap
  
 

 
  
   org.jboss.resteasy.plugins.spring.SpringContextLoaderListener
  
 

 
  Resteasy
  
   org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher
  
 
 
 
  Resteasy
  /*
 


This will initialize RESTEasy and Spring. RESTEasy includes SpringBeanProcesor which is an implementation of BeanFactoryPostProcessor. This bean processor checks whether the created bean contains RESTEasy annotation and if it does then adds it to the RESTEasy repository.
RESTEasy repository is initialized by ResteasyBootstrap class. So the sequence must be in the order which is specified above.

There is a problem (Bug#1012) with Spring 4 and RESTEasy (3.0.6 version) integration. SpringContextLoaderListener of RESTEasy has overridden createContextLoader method from ContextLoaderListener class of Spring which was deprecated in Spring 3.0 and has been removed in Spring 4.
To fix this issue, we need to provide our own implementation of Spring ContextLoaderListener which will register RESTEasy's SpringBeanProcessor and integration will work.

public class PatchedSpringContextLoaderListener extends ContextLoaderListener {

 private SpringContextLoaderSupport springContextLoaderSupport = new SpringContextLoaderSupport();
  
 @Override
 public void contextInitialized(ServletContextEvent event) {
  System.out.println("Initializing context");
  
  boolean scanProviders = false;
  boolean scanResources = false;
 
  String sProviders = event.getServletContext().getInitParameter(
    "resteasy.scan.providers");
  if (sProviders != null) {
   scanProviders = Boolean.valueOf(sProviders.trim());
  }
  String scanAll = event.getServletContext().getInitParameter(
    "resteasy.scan");
  if (scanAll != null) {
   boolean tmp = Boolean.valueOf(scanAll.trim());
   scanProviders = tmp || scanProviders;
   scanResources = tmp || scanResources;
  }
  String sResources = event.getServletContext().getInitParameter(
    "resteasy.scan.resources");
  if (sResources != null) {
   scanResources = Boolean.valueOf(sResources.trim());
  }
 
  if (scanProviders || scanResources) {
   throw new RuntimeException(
     "You cannot use resteasy.scan, resteasy.scan.resources, or resteasy.scan.providers with the SpringContextLoaderLister as this may cause serious deployment errors in your application");
  }
 
  super.contextInitialized(event);
 } 

 @Override
 protected void customizeContext(ServletContext servletContext, ConfigurableWebApplicationContext configurableWebApplicationContext) {
  System.out.println("Customizing context");

  super.customizeContext(servletContext, configurableWebApplicationContext);  
  this.springContextLoaderSupport.customizeContext(servletContext, configurableWebApplicationContext);
 }
 
}

No comments:

Post a Comment

Ads Inside Post