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Chapter 48. Spring Integration

48.1. Basic Integration
48.2. Customized Configuration
48.3. Spring MVC Integration
48.4. JAX-RS with Spring MVC
48.5. Spring Boot starter
48.6. Undertow Embedded Spring Container
48.7. Upgrading in WildFly
48.8. Processing Spring Web REST annotations in RESTEasy

RESTEasy integrates with Springframework in various forms. In this chapter we introduce different methods to integrate Springframework with RESTEasy.

For Maven users, you must use the resteasy-spring artifact. And here is the dependency you should use:

<dependency>
    <groupId>org.jboss.resteasy</groupId>
    <artifactId>resteasy-spring</artifactId>
    <version>4.4.2.Final</version>
</dependency>

RESTEasy comes with its own ContextLoaderListener that registers a RESTEasy specific BeanPostProcessor that processes JAX-RS annotations when a bean is created by a BeanFactory. And it will automatically scan for @Provider and JAX-RS resource annotations on your bean class and register them as JAX-RS resources.

Here is the content that you should add into your web.xml file:

<listener>
    <listener-class>org.jboss.resteasy.plugins.server.servlet.ResteasyBootstrap</listener-class>
</listener>

<listener>
    <listener-class>org.jboss.resteasy.plugins.spring.SpringContextLoaderListener</listener-class>
</listener>

Please note that the SpringContextLoaderListener must be declared after ResteasyBootstrap as it uses ServletContext attributes initialized by it.

And you can configure the Springframework to scan for the JAX-RS resources and beans in a Spring configuration file. The content of the file is shown as follow:

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd

		http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

    <context:component-scan base-package="org.jboss.resteasy.examples.springbasic">
        <context:include-filter type="annotation" expression="javax.ws.rs.Path"/>
    </context:component-scan>
    <context:annotation-config/>

</beans>

Let's say the above file is named resteasy-spring-basic.xml, then in your web.xml the can be configured like this:

<context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:resteasy-spring-basic.xml</param-value>
</context-param>

In addition, you need to configure your RESTEasy servlet in web.xml. Here is the example:

<servlet>
    <servlet-name>Resteasy</servlet-name>
    <servlet-class>org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher</servlet-class>
</servlet>

<servlet-mapping>
    <servlet-name>Resteasy</servlet-name>
    <url-pattern>/rest/*</url-pattern>
</servlet-mapping>

Instead of using HttpServletDispatcher for deployment, you can also use the FilterDispatcher in web.xml:

<filter>
    <filter-name>resteasy-filter</filter-name>
    <filter-class>
        org.jboss.resteasy.plugins.server.servlet.FilterDispatcher
    </filter-class>
</filter>

To see a complete example of the above basic usage, please check the Basic Example we provided.

If you do not want to use the SpringContextLoaderListener provided by RESTEasy, and want to create your bean factories, then you can manually register the RESTEasy BeanFactoryPostProcessor by creating an instance of the RESTEasy SpringBeanProcessor.

And you must configure the RestasyBootstrap into the scope to create the ResteasyDeployment so the relative classes can be fetched from ServletContext.

There is also a SpringBeanProcessorServletAware class that implements the ServletContextAware interface provided by Springframework. The SpringBeanProcessorServletAware can be used to fetch the Registry and ResteasyProviderFactory from the ServletContext.

To demonstrate the above process, we have also provide an example. Please check the Spring and Resteasy Customized Example we provided.

Our Spring integration supports both singletons and the "prototype" scope. RESTEasy handles injecting @Context references. Constructor injection is not supported though. Also, with the "prototype" scope, RESTEasy will inject any @*Param annotated fields or setters before the request is dispatched.

NOTE: You can only use auto-proxied beans with our base Spring integration. You will have undesirable affects if you are doing handcoded proxying with Spring, i.e., with ProxyFactoryBean. If you are using auto-proxied beans, you will be ok.

RESTEasy can also integrate with the Spring DispatcherServlet. The advantages of using this are that you have a simpler web.xml file, you can dispatch to either Spring controllers or RESTEasy from under the same base URL, and finally, the most important, you can use Spring ModelAndView objects as return arguments from @GET resource methods. Setup requires you using the Spring DispatcherServlet in your web.xml file, as well as importing the springmvc-resteasy.xml file into your base Spring beans xml file. Here's an example web.xml file:

<web-app>
   <display-name>Archetype Created Web Application</display-name>

   <servlet>
      <servlet-name>Spring</servlet-name>
      <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
   </servlet>

   <servlet-mapping>
      <servlet-name>Spring</servlet-name>
      <url-pattern>/*</url-pattern>
   </servlet-mapping>
</web-app>

Then within your main Spring beans xml, import the springmvc-resteasy.xml file

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xsi:schemaLocation="
    http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd
    http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.5.xsd
http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
">

    <!-- Import basic SpringMVC RESTEasy integration -->
    <import resource="classpath:springmvc-resteasy.xml"/>
....

You can specify resteasy configuration options by overriding the resteasy.deployment bean which is an instance of ResteasyDeployment. Here's an example of adding media type suffix mappings as well as enabling the RESTEasy asynchronous job service.

<beans xmlns="http://www.springframework.org/schema/beans" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xmlns:p="http://www.springframework.org/schema/p" xmlns:context="http://www.springframework.org/schema/context"
    xmlns:util="http://www.springframework.org/schema/util"
    xsi:schemaLocation="
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.5.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        ">

    <!-- Import basic SpringMVC RESTEasy integration -->
    <import resource="classpath:springmvc-resteasy.xml" />

    <!-- override the bean definition for deployment -->
    <bean id="resteasy.deployment" class="org.jboss.resteasy.spi.ResteasyDeployment" init-method="start" destroy-method="stop">
        <property name="asyncJobServiceEnabled" value="true"/>
        <property name="mediaTypeMappings">
            <map>
                <entry key="json" value="application/json" />
                <entry key="xml" value="application/xml" />
            </map>
        </property>
    </bean>
...

A JAX-RS Application subclass can be combined with a Spring DispatcherServlet and used in the same web application. An application combined in this way allows you to dispatch to either the Spring controller or the JAX-RS resource using the same base URL. In addition you can use the Spring ModelAndView objects as return arguments from @GET resource methods.

Configuring a web application of this type requires a web.xml and spring-servlet.xml file and a reference to springmvc-resteasy.xml. A servlet definition is required for both the Spring DispatcherServlet and the Application subclass in the web.xml, as well as RESTEasy Configuration Switch, resteasy.scan.resources. Here is an example of the minimum configuration information needed in the web.xml.

<web-app>
    <servlet>
        <servlet-name>mySpring</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>mySpring</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>myAppSubclass</servlet-name>
        <servlet-class>org.my.app.EntryApplicationSubclass</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>myAppSubclass</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>

    <!-- required RESTEasy Configuration Switch directs auto scanning
         of the archive for JAX-RS resource files
    -->
    <context-param>
        <param-name>resteasy.scan.resources</param-name>
        <param-value>true</param-value>
    </context-param>
</web-app>

Note that RESTEasy parameters like resteasy.scan.resources may be set in a variety of ways. See Section 3.4, “Configuration” for more information about application configuration.

If your web application contains JAX-RS provider classes the RESTEasy Configuration Switch, resteasy.scan.providers, will also be needed. And if the url-pattern for the JAX-RS Application subclass is other than /* you will need to declare the RESTEasy Configuration Switch, resteasy.servlet.mapping.prefix. This switch can be declare either as a context-param or as a servlet init-param. It's value must be the text that preceeds the /*. Here is an example of such a web.xml.

<web-app>
    <servlet>
        <servlet-name>spring</servlet-name>
        <servlet-class>org.springframework.web.servlet.DispatcherServlet</servlet-class>
    </servlet>
    <servlet-mapping>
        <servlet-name>spring</servlet-name>
        <url-pattern>/*</url-pattern>
    </servlet-mapping>

    <servlet>
        <servlet-name>myAppSubclass</servlet-name>
        <servlet-class>org.my.app.EntryApplicationSubclass</servlet-class>

        <init-param>
            <param-name>resteasy.servlet.mapping.prefix</param-name>
            <param-value>/resources</param-value>
        </init-param>
    </servlet>
    <servlet-mapping>
        <servlet-name>myAppSubclass</servlet-name>
        <url-pattern>/resources/*</url-pattern>
    </servlet-mapping>

    <context-param>
        <param-name>resteasy.scan.resources</param-name>
        <param-value>true</param-value>
    </context-param>
    <context-param>
        <param-name>resteasy.scan.providers</param-name>
        <param-value>true</param-value>
    </context-param>
</web-app>

The spring-servlet.xml file must import springmvc-resteasy.xml, however this file does not need to be present in the archive. In addition a component-scan, declaration of the packages that contain you application classes is needed. At minimum your spring-servlet.xml should contain these statements.

<beans>
    <import resource="classpath:springmvc-resteasy.xml"/>
    <context:component-scan base-package="org.my.app"/>
  </beans>

The RESTEasy project does not include its own component for Spring Boot integration, however PayPal has developed a very interesting RESTEasy Spring Boot starter and shared it with the community. You can see below an example of how to use it. Please refer to the relevant documentation on GitHub for further information.

First, add dependency com.paypal.springboot:resteasy-spring-boot-starter to your Spring Boot application. It is recommended to you use the latest version. Second, optionally you can register one or more JAX-RS application classes. To do so, just define it as a Spring bean, and it will be automatically registered. See the example below.

package com.sample.app;

import org.springframework.stereotype.Component;
import javax.ws.rs.ApplicationPath;
import javax.ws.rs.core.Application;

@Component
@ApplicationPath("/sample-app/")
public class JaxrsApplication extends Application {
}

Finally, to register JAX-RS resources and providers, just define them as Spring beans, and they will be automatically registered. Notice that JAX-RS resources can be singleton or request scoped, while JAX-RS providers must be singletons.

We provide a undertow-based embedded spring container module, called "resteasy-undertow-spring". To use it, you need to add the following additional dependencies into your project:

<dependency>
  <groupId>org.jboss.resteasy</groupId>
  <artifactId>resteasy-undertow</artifactId>
  <scope>test</scope>
</dependency>
<dependency>
  <groupId>org.jboss.resteasy</groupId>
  <artifactId>resteasy-undertow-spring</artifactId>
  <scope>test</scope>
</dependency>

In the "resteasy-undertow-spring" module, we have a embedded server class called "UndertowJaxrsSpringServer". In its "undertowDeployment(...)" method, it will accept the spring context configuration file:

public DeploymentInfo undertowDeployment(String contextConfigLocation, String mapping)

We can provide a minimal spring config like the following:

<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:p="http://www.springframework.org/schema/p"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:util="http://www.springframework.org/schema/util"
       xsi:schemaLocation="
        http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context-2.5.xsd
        http://www.springframework.org/schema/util http://www.springframework.org/schema/util/spring-util-2.5.xsd
        http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
        ">
    <context:component-scan base-package="org.jboss.resteasy.springmvc.test"/>
    <context:annotation-config/>
    <import resource="classpath:springmvc-resteasy.xml"/>
</beans>

In above configuration, the "springmvc-resteasy.xml" in the classpath is provided by the "resteasy-spring" module by default. Let's name the above configuration file with "spring-servlet.xml", and the following code will include it and setup the UndertowJaxrsSpringServer and start it:

UndertowJaxrsSpringServer server = new UndertowJaxrsSpringServer();
server.start();

DeploymentInfo deployment = server.undertowDeployment("classpath:spring-servlet.xml", null);
deployment.setDeploymentName(BasicSpringTest.class.getName());
deployment.setContextPath("/");
deployment.setClassLoader(BasicSpringTest.class.getClassLoader());

server.deploy(deployment);

Above is the code example to setup and start UndertowJaxrsSpringServer. To see a complete example, please check the resteasy-springMVC as demo app.

Note. As noted inSection 3.1.2, “Upgrading RESTEasy within WildFly”, the RESTEasy distribution comes with a zip file called resteasy-jboss-modules-<version>.zip, which can be unzipped into the modules/system/layers/base/ directory of WildFly to upgrade to a new version of RESTEasy. Because of the way resteasy-spring is used in WildFly, after unzipping the zip file, it is also necessary to remove the old resteasy-spring jar from modules/system/layers/base/org/jboss/resteasy/resteasy-spring/main/bundled/resteasy-spring-jar.

RESTEasy also provides the ability to process Spring Web REST annotations (i.e. Spring classes annotated with @RestController) and handle related REST requests without delegating to Spring MVC. This functionality is currently experimental.

In order for RESTEasy to be able to process Spring @RestController, you first need to include the following dependency.

<dependency>
                <groupId>org.jboss.resteasy</groupId>
                <artifactId>resteasy-spring-web</artifactId>
                <version>4.4.2.Final</version>
                </dependency>

            

Currently RESTEasy does not auto-scan for @RestController annotated classes, so you need to add all @RestController annotated classes to your web.xml file as shown in the following example.

<web-app>
   <display-name>RESTEasy application using Spring REST annotations</display-name>

    <context-param>
        <param-name>resteasy.scanned.resource.classes.with.builder</param-name>
        <param-value>org.jboss.resteasy.spi.metadata.SpringResourceBuilder:org.example.Controller1,org.example.Controller2</param-value>
    </context-param>

   ...
</web-app>

In the example above, Controller1 and Controller2 are registered and are expected to be annotated with @RestController.

The list of the currently supported annotations can be found below

Table 48.1. 

AnnotationComment
@RestController 
@RequestMapping 
@GetMapping 
@PostMapping 
@PutMapping 
@DeleteMapping 
@PatchMapping 
@RequestParam 
@RequestHeader 
@MatrixVariable 
@PathVariable 
@CookieValue 
@RequestBody 
@ResponseStatusOnly supported as a method annotation
@RequestParam 

Furthermore, the use of org.springframework.http.ResponseEntity as a return value is supported as is the use of javax.servlet.http.HttpServletRequest and javax.servlet.http.HttpServletResponse as method parameters