RESTEasy + Tomcat hello world application

RESTEasy is JBOSS provided implementation of JAX-RS specification for building RESTful Web Services and RESTful Java applications. Though this is not limited to be used in JBOSS only, and you can use with other servers also. In this post, I am building such a hello world application in tomcat server.

Environment used:

  1. RESTEasy 2.3.1.GA
  2. Tomcat 7
  3. JDK 1.6

Follow below steps to build a demo application.

1) Create a maven project and convert to eclipse web project

mvn archetype:generate -DgroupId=com.howtodoinjava -DartifactId=RESTfulDemoApplication 
-DarchetypeArtifactId=maven-archetype-webapp -DinteractiveMode=false

mvn eclipse:eclipse -Dwtpversion=2.0

2) Update runtime dependencies in pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
  xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
  <modelVersion>4.0.0</modelVersion>
  <groupId>com.howtodoinjava</groupId>
  <artifactId>RESTfulDemoApplication</artifactId>
  <packaging>war</packaging>
  <version>1.0-SNAPSHOT</version>
  <name>RESTfulDemoApplication Maven Webapp</name>
  <url>http://maven.apache.org</url>
  <repositories>
   	<repository>
      <id>jboss</id>
      <url>http://repository.jboss.org/maven2</url>
   	</repository>
  </repositories>
  <dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>3.8.1</version>
      <scope>test</scope>
    </dependency>
    <!-- core library -->
	<dependency>
		<groupId>org.jboss.resteasy</groupId>
		 <artifactId>resteasy-jaxrs</artifactId>
		<version>2.3.1.GA</version>
	</dependency>
	<dependency>
		<groupId>net.sf.scannotation</groupId>
		<artifactId>scannotation</artifactId>
		<version>1.0.2</version>
	</dependency>
  </dependencies>
  <build>
    <finalName>RESTfulDemoApplication</finalName>
  </build>
</project>

3) Update web.xml file for resteasy specific servlet mapping

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  	<display-name>Archetype Created Web Application</display-name>
  	<!-- Auto scan REST service -->
	<context-param>
		<param-name>resteasy.scan</param-name>
		<param-value>true</param-value>
	</context-param>
	
	<servlet>
		<servlet-name>resteasy-servlet</servlet-name>
		<servlet-class>
			org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher
		</servlet-class>
	</servlet>
 
	<servlet-mapping>
		<servlet-name>resteasy-servlet</servlet-name>
		<url-pattern>/*</url-pattern>
	</servlet-mapping>
</web-app>

4) Write a service class having @Path annotations

package com.howtodoinjava.restful;

import javax.ws.rs.GET;
import javax.ws.rs.Path;
import javax.ws.rs.core.Response;

@Path("/user-management")
public class UserManagementModule
{
	@GET
	@Path("/users")
	public Response getAllUsers()
	{
		String result = "<h1>RESTful Demo Application</h1>In real world application, a collection of users will be returned !!";
		return Response.status(200).entity(result).build();
	}
}

5) Run the application

When we deploy above built application in tomcat and hit the URL: ” http://localhost:8080/RESTfulDemoApplication/user-management/users”, below is the response.

JAX-RS + Tomcat example

JAX-RS + Tomcat example

To download the source code of above example, click below link.

 

Download Source code 

 

Happy Learning !!

21 thoughts on “RESTEasy + Tomcat hello world application”

  1. HI Lokesh,
    will it make any difference in running 10 different war files in single tomcat vs multiple instances of tomcat (only one catalina_home and 10 different catalinabase)

    is there any pros & cons in running multiple instances of tomcat? will it help in performance? or etc

    1. I don’t think that any performance gain will be there. A good benefit I see is instance specific configuration ability. This configuration can be related to application runtime configuration as well as security settings such as different access rights to specific folders for different application users.

  2. Hi Lokesh,

    I have developed a sample RestFul java application with Spring.I want generate WADL file for that project.How? My IDE is RAD.
    Please help me out.
    Thanks

  3. may i know how can we use bugzilla rest api methods to create bug , search bugs in bugzilla with java program automatically.

  4. Please help me how to use bugzilla rest api methods with java. I want to search, create bugs in bugzilla through java program.

  5. HI Lokesh, can you help me how to use REST API methods of bugzilla with Java. I am newer to Webservices so Please advise me which tool do i need to use JSON or Apache Client .

    1. Currently I do not have clear understanding of client APIs of Bugzilla. I will try to find time to do some research on this. My advice: try to find some already existing client API supporting request-response to bugzilla. Don’t write everything from scratch.

  6. HI Lokesh,

    I have a scenario where I need to develop a restful service using tomcat and jersey. Following is what needs to be done.
    It a post service which I have created, now when a request comes in I need to send one response immediately/synchronously and send back a second response asynchronously. Could you please let me know how to achieve it.

  7. getting this error:
    22:22:12,279 ERROR [org.jboss.remoting.remote.connection] (Remoting “vostro:MANAGEMENT” read-1) JBREM000200: Remote connection failed: java.io.IOException: An existing connection w
    as forcibly closed by the remote host
    22:22:41,585 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/RESTfulDemoApplication]] (http–127.0.0.1-8080-1) StandardWrapper.Throwable: java.lang.Runti
    meException: Unable to find a public constructor for class org.jboss.resteasy.core.AsynchronousDispatcher
    at org.jboss.resteasy.plugins.server.resourcefactory.POJOResourceFactory.registered(POJOResourceFactory.java:35) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.core.ResourceMethodRegistry.addResourceFactory(ResourceMethodRegistry.java:121) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.core.ResourceMethodRegistry.addResourceFactory(ResourceMethodRegistry.java:107) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.core.ResourceMethodRegistry.addResourceFactory(ResourceMethodRegistry.java:84) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.core.ResourceMethodRegistry.addPerRequestResource(ResourceMethodRegistry.java:73) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.spi.ResteasyDeployment.registration(ResteasyDeployment.java:367) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.spi.ResteasyDeployment.start(ResteasyDeployment.java:225) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.init(ServletContainerDispatcher.java:67) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.init(HttpServletDispatcher.java:36) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1202) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:952) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:188) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.13.Final.jar:]
    at org.jboss.modcluster.container.jbossweb.JBossWebContext$RequestListenerValve.event(JBossWebContext.java:67)
    at org.jboss.modcluster.container.jbossweb.JBossWebContext$RequestListenerValve.invoke(JBossWebContext.java:48)
    at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671) [jbossweb-7.0.13.Final.jar:]
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) [jbossweb-7.0.13.Final.jar:]
    at java.lang.Thread.run(Thread.java:662) [rt.jar:1.6.0_45]

    22:22:41,626 ERROR [org.apache.catalina.core.ContainerBase.[jboss.web].[default-host].[/RESTfulDemoApplication].[resteasy-servlet]] (http–127.0.0.1-8080-1) Allocate exception for
    servlet resteasy-servlet: java.lang.RuntimeException: Unable to find a public constructor for class org.jboss.resteasy.core.AsynchronousDispatcher
    at org.jboss.resteasy.plugins.server.resourcefactory.POJOResourceFactory.registered(POJOResourceFactory.java:35) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.core.ResourceMethodRegistry.addResourceFactory(ResourceMethodRegistry.java:121) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.core.ResourceMethodRegistry.addResourceFactory(ResourceMethodRegistry.java:107) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.core.ResourceMethodRegistry.addResourceFactory(ResourceMethodRegistry.java:84) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.core.ResourceMethodRegistry.addPerRequestResource(ResourceMethodRegistry.java:73) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.spi.ResteasyDeployment.registration(ResteasyDeployment.java:367) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.spi.ResteasyDeployment.start(ResteasyDeployment.java:225) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.init(ServletContainerDispatcher.java:67) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.init(HttpServletDispatcher.java:36) [resteasy-jaxrs-2.3.2.Final.jar:]
    at org.apache.catalina.core.StandardWrapper.loadServlet(StandardWrapper.java:1202) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardWrapper.allocate(StandardWrapper.java:952) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:188) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:161) [jbossweb-7.0.13.Final.jar:]
    at org.jboss.modcluster.container.jbossweb.JBossWebContext$RequestListenerValve.event(JBossWebContext.java:67)
    at org.jboss.modcluster.container.jbossweb.JBossWebContext$RequestListenerValve.invoke(JBossWebContext.java:48)
    at org.jboss.as.web.security.SecurityContextAssociationValve.invoke(SecurityContextAssociationValve.java:153) [jboss-as-web-7.1.1.Final.jar:7.1.1.Final]
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:155) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:102) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:109) [jbossweb-7.0.13.Final.jar:]
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:368) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:877) [jbossweb-7.0.13.Final.jar:]
    at org.apache.coyote.http11.Http11Protocol$Http11ConnectionHandler.process(Http11Protocol.java:671) [jbossweb-7.0.13.Final.jar:]
    at org.apache.tomcat.util.net.JIoEndpoint$Worker.run(JIoEndpoint.java:930) [jbossweb-7.0.13.Final.jar:]
    at java.lang.Thread.run(Thread.java:662) [rt.jar:1.6.0_45]

  8. I’m trying to get this to work in wildfly-8.0.0.Alpha3 but without success. I notice in the JBoss tutorial (which is deployed perfectly in wildfly but not in tomcat) that there are some differences. The web.xml is quite small there and there is a registration of the application path as well. I tried both but without success. Can you point me to the right direction? Why isn’t there a hello world for both servers?

    1. Jboss has inbuilt support for resteasy tht’ why you don’t need to specify anything extra in web.xml while tomcat demands external configuration.

      Can you please look at logs and see if there is any error on tomcat server logs? Paste that here.

      1. there is nothing wrong in the tomcat logs, the tutorial works great for tomcat. What I’m trying to do is make it work for wildfly (jboss) as well.

        I added an ApplicationConfig class, and I emptied the web.xml file and now it works!

        Do you have any idea why this part causes a problem for jboss?

        resteasy-servlet

        org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher

        Thans a lot!!!

Note:- In comment box, please put your code inside [java] ... [/java] OR [xml] ... [/xml] tags otherwise it may not appear as intended.

Leave a Reply

Your email address will not be published. Required fields are marked *


nine × = 45

You may use these HTML tags and attributes: <a href="" title=""> <abbr title=""> <acronym title=""> <b> <blockquote cite=""> <cite> <code> <del datetime=""> <em> <i> <q cite=""> <strike> <strong>