RestFul Webservices @QueryParam Example

JAX-RS Binding values to method parameters

To call any service we need to bind the request to the resource method, in order to bind this JAX-RS has provided few parameter types, the data will be taken from these parameters by using the annotaions. Whenever JAX-RS provider receives an http request, it finds an appropriate java method  that can service this request.

Here are the parameters provided by JAX-RS API

1. Query parameters
2. URI path parameters
3. Header parameters
4. Form parameters
5. Cookie parameters
6. Matrix parameters
7. Bean Parameters

In this example we will see how to use all these parameters.

1. Create a maven project using the quick start archetype and add below dependencies in your pom.xml file

<dependency>
   <groupId>org.eclipse.jetty</groupId>
   <artifactId>jetty-server</artifactId>
   <version>9.2.3.v20140905</version>
  </dependency>
  <dependency>
   <groupId>org.eclipse.jetty</groupId>
   <artifactId>jetty-servlet</artifactId>
   <version>9.2.3.v20140905</version>
  </dependency>
  <dependency>
   <groupId>org.glassfish.jersey.core</groupId>
   <artifactId>jersey-server</artifactId>
   <version>2.7</version>
  </dependency>
  <dependency>
   <groupId>org.glassfish.jersey.containers</groupId>
   <artifactId>jersey-container-servlet-core</artifactId>
   <version>2.7</version>
  </dependency>
  <dependency>
   <groupId>org.glassfish.jersey.containers</groupId>
   <artifactId>jersey-container-jetty-http</artifactId>
   <version>2.7</version>
  </dependency>
  <dependency>
   <groupId>org.glassfish.jersey.media</groupId>
   <artifactId>jersey-media-moxy</artifactId>
   <version>2.7</version>
  </dependency>

2. Create a simple service which uses all these params

package com.vinod.vinod_rest_examples;

import javax.ws.rs.Consumes;
import javax.ws.rs.FormParam;
import javax.ws.rs.GET;
import javax.ws.rs.HeaderParam;
import javax.ws.rs.MatrixParam;
import javax.ws.rs.POST;
import javax.ws.rs.Path;
import javax.ws.rs.PathParam;
import javax.ws.rs.Produces;
import javax.ws.rs.QueryParam;
import javax.ws.rs.core.MediaType;

@Path("/DataBinding")

public class DataBinding {

 /**
*http://localhost:8080/DataBinding/queryParam?name=vinod
*
*@param name
*@return
 */
 @GET
 @Path("queryParam")
 @Produces(MediaType.APPLICATION_JSON)
 public String queryParam(@QueryParam("name") String name) {
  return "Hello world " + name;
 }

 /**
*http://localhost:8080/DataBinding/vinod/pathParam
*
*@param name
*@return
 */
 @GET
 @Path("{name}/pathParam")
 @Produces(MediaType.APPLICATION_JSON)
 public String pathParam(@PathParam("name") String name) {
  return "Hello world " + name;
 }

 /**
*http://localhost:8080/DataBinding/headerParam
*
*@param userAgent
*@return
 */
 @Path("headerParam")
 @GET
 @Produces(MediaType.APPLICATION_JSON)

 public String headerParam(@HeaderParam("user-agent") String userAgent) {
  return "Hello world " + userAgent;
 }

 /**
*http://localhost:8080/DataBinding/matrixParam;name=vinod;address=
* bangalore
*
*@param name
*@param address
*@return
 */
 @Path("matrixParam")
 @GET
 @Produces(MediaType.APPLICATION_JSON)

 public String matrixParam(@MatrixParam("name") String name, @MatrixParam("address") String address) {
  return "Hello world " + name + " " + address;
 }

 /**
*http://localhost:8080/DataBinding/formParam pass the name in the form
* request
*
*@param name
*@return
 */
 @Path("formParam")
 @POST
 public String formParam(@FormParam("name") String name) {
  return "Hello world " + name;
 }
}

3. Create a java class to start jetty server

package com.vinod.vinod_rest_examples;

import org.eclipse.jetty.server.Server;
import org.eclipse.jetty.servlet.ServletContextHandler;
import org.eclipse.jetty.servlet.ServletHolder;

/**
 * Hello world!
 *
 */
public class App {
 public static void main(String[] args) {
  ServletContextHandler context = new ServletContextHandler(ServletContextHandler.SESSIONS);
  context.setContextPath("/");

  Server jettyServer = new Server(8080);
  jettyServer.setHandler(context);

  ServletHolder jerseyServlet = context.addServlet(org.glassfish.jersey.servlet.ServletContainer.class, "/*");
  jerseyServlet.setInitOrder(0);

  // Setting pacakge name over here to load services
  jerseyServlet.setInitParameter("jersey.config.server.provider.packages",
    "com.vinod.vinod_rest_examples");
  try {
   jettyServer.start();
   jettyServer.join();
  } catch (Exception e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
  } finally {
   jettyServer.destroy();
  }
 }
}

4. Hit the urls for testing

http://localhost:8080/DataBinding/queryParam?name=vinod

http://localhost:8080/DataBinding/vinod/pathParam

http://localhost:8080/DataBinding/headerParam

http://localhost:8080/DataBinding/matrixParam;name=vinod;address=bangalore

http://localhost:8080/DataBinding/formParam pass the name in the form

Download this example!! https://github.com/kkvinodkumaran/myrepository/tree/master/vinod-rest-examples