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.
Jackson is is a multi-purpose Java library for processing JSON data format. Jackson aims to be the best possible combination of fast, correct, lightweight, and ergonomic for developers.
In this post, I am demonstrating the way to use Jackson with RESTEasy, to convert the API response in json format.
Environment used:
- RESTEasy 2.3.1.GA
- RESTEasy Jackson provider 2.3.1
- Tomcat 7
- 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> <!-- Jackson support --> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-jackson-provider</artifactId> <version>2.3.1.GA</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 and model class
User.java
package com.howtodoinjava.model; import java.io.Serializable; import javax.xml.bind.annotation.XmlAccessType; import javax.xml.bind.annotation.XmlAccessorType; import javax.xml.bind.annotation.XmlAttribute; import javax.xml.bind.annotation.XmlElement; import javax.xml.bind.annotation.XmlRootElement; @XmlAccessorType(XmlAccessType.NONE) @XmlRootElement(name = "user") public class User implements Serializable { private static final long serialVersionUID = 1L; @XmlAttribute(name = "id") private int id; @XmlElement(name = "firstName") private String firstName; @XmlElement(name = "lastName") private String lastName; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getLastName() { return lastName; } public void setLastName(String lastName) { this.lastName = lastName; } }
UserManagementModule.java
package com.howtodoinjava.service; import javax.ws.rs.GET; import javax.ws.rs.Path; import javax.ws.rs.PathParam; import javax.ws.rs.core.Response; import com.howtodoinjava.model.User; @Path("/user-management") public class UserManagementModule { @GET @Path("/users/{id}") @Produces("application/json") public Response getUserById(@PathParam("id") Integer id) { User user = new User(); user.setId(id); user.setFirstName("Lokesh"); user.setLastName("Gupta"); return Response.status(200).entity(user).build(); } }
5) Run the application
When we deploy above built application in tomcat and hit the URL: ” http://localhost:8080/RESTfulDemoApplication/user-management/users/10″, below is the response.

Click below to download source code for this example.
Download Source code
Happy Learning !!
Thanks. I can see User.java has warning related to JAXB. One need to add following dependency to vanish those warnings –
javax.xml
jaxb-api
2.1
Hi Lokesh,
I want to know how can we perform session management using RestEasy.
What are the different ways in which we can do it and how they can be done.
Please help.
Thanks in advance.
AP
Ok. Ignore my earlier messages. I was making some mistake. Let me investigate and post what I did wrong for other’s benefit.
apologies for being so dumb and copy pasting wrong error message. I was trying different URLs. I get this error with user-management in URL..
Could not find resource for relative : /user-management/users/10 of full path: http://localhost:8080/RESTfulDemoApplication/user-management/users/10
Lokesh
First, a big thanks for sharing your experience.
I tried your instructions and am facing some challenges. I am using eclipse Java EE IDE Indigo & Apache Tomcat/7.0.34. My RestEasy jar is at 2.3.1
1. I created project using MVN command. While importing in eclipse, I see an error “Eclipse Maven Import error: An internal error occurred during: Importing Maven projects. Unsupported IClasspathEntry kind=4”. I could get rid of this by doing “eclipse->project->Run as->maven clean” &
“eclipse->project->Run as->maven install”
2. While trying to run this project on tomcat (from eclipse), I notice following error. I checked eclipse output directory and didn’t see any apps deployed under wtpwebapps folder.
java.lang.IllegalArgumentException: Document base C:dgoyalmystuffmycodeeclipseworkspace.metadata.pluginsorg.eclipse.wst.server.coretmp0wtpwebappsRESTfulDemoApplication does not exist or is not a readable directory
at org.apache.naming.resources.FileDirContext.setDocBase(FileDirContext.java:138)
at org.apache.catalina.core.StandardContext.resourcesStart(StandardContext.java:4906)
at org.apache.catalina.core.StandardContext.startInternal(StandardContext.java:5086)
at org.apache.catalina.util.LifecycleBase.start(LifecycleBase.java:150)
….. more stack trace —
3. Finally, I exported this project as a .war file to webapps folder. However, now I get an error
HTTP Status 404 – Could not find resource for relative : /users/10 of full path: http://localhost:8080/RESTfulDemoApplication/users/10
Any suggestions or ideas?
My reference libraries are at
jsr250-api-1.0
activation-1.1
junit-3.8.1
resteasy-jaxrs-2.3.1.GA
jaxrs-api-2.3.1.GA.jar
commons-httpclient-3.1
commons-logging-1.0.4
commons-codec-1.2
httpclient-4.1.2
httpcore-4.1.2
jcip-annotations-1.0
scannotations-1.0.2
javaassist-3.6.0.GA
Thanks
Can you please follow below steps:
https://stackoverflow.com/questions/10564684/how-to-fix-error-updating-maven-project-unsupported-iclasspathentry-kind-4
Thanks. As I wrote, I already resolved issue#1. I am now stuck at issue#3. I would appreciate any suggestions.
thanks
You forgot “user-management” in path. Please see the image in post.
I am giving full path http://localhost:8080/RESTfulDemoApplication/users/10
If there a way to configure high level DEBUG or trace logs for RESTEasy?
Error message also shows myURL correctly.
“Could not find resource for relative : /users/10 of full path: http://localhost:8080/RESTfulDemoApplication/users/10“