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How to Create a Web Service Using JBoss and JAX-RS

Web Services give us access to extra functionality without writing more code.

TiOluwa Olarewaju

• 4 min read
How to Create a Web Service Using JBoss and JAX-RS

You’re the head of development at a new credit card company and your team has built a great product.

Well, almost.You can't send anyone a new card until you verify their credit history. And if you build that functionality yourself, it will slow down development.

So what do you do?

You borrow the functionality from a company that has already figured this out.

And to do that, you use a web service.

Why Do We Use Web Services?

Web services help us build software quickly because they give us access to extra functionality without writing more code.

A web service is a method that our application can use over the internet.

How Do We Use Web Services?

Our Final Architecture

What You’ll Need

Create Data Model

Step 1: Open JBoss Developer Studio

Step 2: Create a new Maven project called simple-data-model (Steps here)

Step 3: Create a class called CreditReport

  • Make it serializable 
public class CreditReport implements Serializable
  • Add a default serial version id 
private static final long serialVersionUID = 1L;
  • Add a constructor
public CreditReport(){ 
}

Step 4: Create fields to store credit report data

  • Create three variables 
private String fullname; 
private String ssn; 
private Integer creditScore;
  • Create getters & setters for each field
  • Click Source -> Generate Getters & Setters

Step 5: Build the project

  • Right click project -> Run as -> Maven Build
Goals: clean install

Create a REST Web Service

Step 1: Create a new maven project called simple-rest-service

Step 2: Update Maven

  • In your pom.xml file, click the pom.xml tab and change the packaging type <packaging>war</packaging>
  • Add dependencies: resteasy-jaxrs (provided), simple-data-model
  • Right click your project -> Maven -> Update Project

Step 3: Add web descriptors

  • In the /src/main/webapp/WEB-INF directory, create a file called jboss-web.xml
<?xml version="1.0" encoding="UTF-8"?>
<jboss-web>     
    <context-root>simple-ejb-project</context-root> 
</jboss-web>
  • In the same directory, create a file called web.xml
<web-app version="3.0" xmlns="http://java.sun.com/xml/ns/javaee"
        xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
        xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd">
    <servlet-mapping>         
        <servlet-name>javax.ws.rs.core.Application</servlet-name>
        <url-pattern>/rest/*</url-pattern>    
    </servlet-mapping>
</web-app>

Step 4: Create a class called CreditReportService

  • Add @Path annotation 
@Path("/creditReport")
public class CreditReportService
  • Add a method called getCreditReport
@GET 
@Path("/get")
@Produces("application/json")
public CreditReport getCreditReport(             
        @QueryParam("fullname") String fullname,
        @QueryParam("ssn") String ssn){ 
        
    CreditReport creditReport = new CreditReport();
    creditReport.setFullname(fullname);   
    creditReport.setSsn(ssn); 
        
    Random rand = new Random();
    int randomCreditScore = rand.nextInt((700 - 400) + 1) + 400;
    creditReport.setCreditScore(new Integer(randomCreditScore)); 
        
    return creditReport;
}

Step 5: Build the project

  • Right click project -> Run as -> Maven Build
Goals: clean install
  • Deploy the project to your JBoss EAP server

Test Web Service

To send a web request, point your browser at http://localhost:8080/simple-rest-service/rest/creditReport/get?fullname=YourName&ssn=666121923

You should get a response as a JSON dictionary

Great! Let's review what we just did.

Recap

Create Data Model

  • We created a Credit Report model to send data from our web service

Create a REST Web Service

1: We added a descriptor to tell JBoss that we have a REST service (web.xml)

2: We added RESTEasy dependencies

  • REST - a set of rules for creating web services
  • JAX-RS - a Java API specification for REST
  • RESTEasy - a Java framework for building REST Web services. It is an implementation of JAX-RS

3: We added JAX-RS annotations to create a CreditReport web service

  • @Path - the path to our web service (/creditReport/get)
  • @GET - this method will be used to retrieve data
  • @Produces - the format of the data sent back to the client
  • JSON (JavaScript Object Notation) - a format for transmitting data
  • @QueryParam - this method has two parameters

Test Web Service

To access our web service, we took the base URL,

http://localhost:8080/simple-web-service

the URL pattern (web.xml)

/rest

the path to our method (@Path)

/creditReport/get

and our parameters

?fullname=YourName&ssn=666121923

to get our final URL

http://localhost:8080/simple-rest-service/rest/creditReport/get?fullname=YourName&ssn=666121923

Note: Usually an application would call the getCreditReport method, but for this example, we are viewing it in the browser.

What's a best practice for Web Services?

It's a good practice to choose JSON over XML to send data over a web service.

Since JSON is a more compact data format, your data will bent sent and processed faster than if you used XML.

So...

  1. Web services give us access to extra functionality without writing more code
  2. We can use JAX-RS annotations to define a RESTful web service
  3. Use JSON over XML to send/receive data quickly
  1. Project Source Code
  2. REST & JAX-RS Summary
  3. Other Web Service Types

That's all for today!

Happy Coding,

-T.O.