Big Data/Analytics Zone is brought to you in partnership with:

Over 25 years experience, specializing in business technology in the areas of web application development and collaborative computing I been working as an architect-developer for applications or product development. I am particularly interested in organizations that use leading technologies such as Android, Springs, Spring-WebFlow, JSP’s, Servlets, XML, Java, Struts, PHP, LDAP, Maven, JUnit and Web Application Servers. I have a very solid background with Java, OOP, Design-Patterns and Multi-Threading. I am also able to interface with all levels of management! My consulting services enable businesses maximize value from their business process initiatives and IT investments leading to improved organizational performance. Our services leverage business knowledge, process excellence, technology expertise and substantial domain experience in chosen industry verticals. Johnathan Mark has posted 7 posts at DZone. You can read more from them at their website. View Full User Profile

How To Use Spring RESTTemplate To Post Data to a Web Service

06.22.2013
| 31000 views |
  • submit to reddit

 

Using Spring RESTTemplate to Post Objects to RESTful web services with Spring’s Java Configuration (JavaConfig) style with Maven, JUnit, Log4J

In this example I am going to show you how to post data to a RESTful web service in Java using Spring, Spring Java Configuration and more

Web Service Code

Let’s take a quick look at the Spring MVC Web Service code on the server:

@Controller
@RequestMapping("/api")
class JSonController
{

    private static final Logger logger = LoggerFactory.getLogger(JSonController.class);
    @RequestMapping(value = "/{id}", method = RequestMethod.POST)
    @ResponseBody
    public User updateCustomer(@PathVariable("id") String id, @RequestBody User user) {

        logger.debug("I am in the controller and got ID: " + id.toString());
        logger.debug("I am in the controller and got user name: " + user.toString());

        return new User("NEW123", "NEW SMITH");
    }

As you can see from the code above the web service is goign to what for a ID and user object to be passed in and then its going to create a new User Object and send it back to the client.

Lets take a quick look inside the User Object

public class User
{
    private String user;
    private String name;
    public User()
    {
    }

    public User(String user, String name)
    {
        this.user = user;
        this.name = name;
    }

    public String getUser()
    {
        return user;
    }

    public void setUser(String user)
    {
        this.user = user;
    }

    public String getName()
    {
        return name;
    }

    public void setName(String name)
    {
        this.name = name;
    }
}

So you can see from the above code that the user object has to fields user and name.

Time For The Client Code

You can see from the client code below is that we are using Spring RESTTemaple and going to post an User Object to a web server and get one back.

@PropertySource("classpath:application.properties")
public class Main
{

    /**
     * Setting up logger
     */
    private static final Logger LOGGER = getLogger(Main.class);
    public static void main(String[] args) throws IOException
    {
        LOGGER.debug("Starting REST Client!!!!");

        /**
         *
         * This is going to setup the REST server configuration in the applicationContext
         * you can see that I am using the new Spring's Java Configuration style and not some OLD XML file
         *
         */
        ApplicationContext context = new AnnotationConfigApplicationContext(RESTConfiguration.class);

        /**
         *
         * We now get a RESTServer bean from the ApplicationContext which has all the data we need to
         * log into the REST service with.
         *
         */
        RESTServer mRESTServer = context.getBean(RESTServer.class);
        /**
         *
         * Setting up data to be sent to REST service
         *
         */
        Map<String, String> vars = new HashMap<String, String>();
        vars.put("id", "JS01");
        /**
         *
         * Doing the REST call and then displaying the data/user object
         *
         */
        try
        {

            /*

                This is code to post and return a user object

             */

            RestTemplate rt = new RestTemplate();
            rt.getMessageConverters().add(new MappingJacksonHttpMessageConverter());
            rt.getMessageConverters().add(new StringHttpMessageConverter());

            String uri = new String("http://" + mRESTServer.getHost() + ":8080/springmvc-resttemplate-test/api/{id}");

            User u = new User();
            u.setName("Johnathan M Smith");
            u.setUser("JS01");

            User returns = rt.postForObject(uri, u, User.class, vars);

            LOGGER.debug("User:  " + u.toString());

        }
        catch (HttpClientErrorException e)
        {
            /**
             *
             * If we get a HTTP Exception display the error message
             */

            LOGGER.error("error:  " + e.getResponseBodyAsString());

            ObjectMapper mapper = new ObjectMapper();
            ErrorHolder eh = mapper.readValue(e.getResponseBodyAsString(), ErrorHolder.class);

            LOGGER.error("error:  " + eh.getErrorMessage());

        }
        catch(Exception e)
        {
            LOGGER.error("error:  " + e.getMessage());

        }
    }

}

You can see from the above code how easy it is to use RESTTeample to post data to a web service.

We Can I Get The Source Code

You can checkout the project from github.

git clone git@github.com:JohnathanMarkSmith/springmvc-resttemplate-test.git
cd springmvc-resttemplate-test.git

If you have any questions or comments please email me at john@johnathanmarksmith.com

Published at DZone with permission of its author, Johnathan Mark Smith.

(Note: Opinions expressed in this article and its replies are the opinions of their respective authors and not those of DZone, Inc.)