JAX-RS 2.0 has brought lots of improvement over previous version. One of major improvement is client API which was completely missing in JAX-RS 1.0. While it was easy to write a portable JAX-RS service, each JAX-RS implementation defined their own proprietary API. JAX-RS 2.0 fills in this gap with a fluent, low-level, request building API. Here’s a simple example:
Client client = ClientFactory.newClient(); WebTarget target = client.target("http://localhost:8080/howtodoinjava"); Form form = new Form().param("customer", "Bill").param("product", "book"); Response response = target.request().post(Entity.form(form)); Order order = response.readEntity(Order.class);
Above code is JAX-RS 2.0 specific and uses JAX-RS classes. If you are using latest RESTEasy (version 3) build then you can use these lower level JAX-RS 2.0 APIs from RESTEasy abstraction provided by its client API.
JAX-RS RESTEasy APIs
Let’s take an example web-service APIs which we will access in our client code:
@GET @Path("/users") @Produces("application/vnd.com.demo.user-management.users+xml;charset=UTF-8;version=1") public Users getAllUsers() { User user1 = new User(); user1.setId(1); user1.setFirstName("demo"); user1.setLastName("user"); user1.setUri("/user-management/users/1"); User user2 = new User(); user2.setId(2); user2.setFirstName("Mark"); user2.setLastName("Dwain"); user2.setUri("/user-management/users/2"); Users users = new Users(); users.setUsers(new ArrayList<User>()); users.getUsers().add(user1); users.getUsers().add(user2); return users; } @POST @Path("/users") @Consumes("application/vnd.com.demo.user-management.user+xml;charset=UTF-8;version=1") public Response createUser(User user, @DefaultValue("false") @QueryParam("allow-admin") boolean allowAdmin) throws URISyntaxException { System.out.println(user.getFirstName()); System.out.println(user.getLastName()); return Response.status(201) .contentLocation(new URI("/user-management/users/123")).build(); }
Client code
Now let’s access these APIs using new client code:
package test.jaxrs2; import javax.ws.rs.client.Entity; import javax.ws.rs.core.Response; import org.jboss.resteasy.client.jaxrs.ResteasyClient; import org.jboss.resteasy.client.jaxrs.ResteasyClientBuilder; import org.jboss.resteasy.client.jaxrs.ResteasyWebTarget; import com.demo.rest.model.User; import com.demo.rest.model.Users; public class Demo_JAXRS_2_Example { public static void main(String[] args) { getExample_one(); getExample_two(); postExample(); } private static void getExample_one() { ResteasyClient client = new ResteasyClientBuilder().build(); ResteasyWebTarget target = client.target("http://localhost:8080/RESTEasyApplication/user-management/users"); Response response = target.request().get(); //Read output in string format String value = response.readEntity(String.class); System.out.println(value); response.close(); } private static void getExample_two() { ResteasyClient client = new ResteasyClientBuilder().build(); ResteasyWebTarget target = client.target("http://localhost:8080/RESTEasyApplication/user-management/users"); Response response = target.request().get(); //Read the entity Users users = response.readEntity(Users.class); for(User user : users.getUsers()){ System.out.println(user.getId()); System.out.println(user.getLastName()); } response.close(); } private static void postExample() { User user = new User(); user.setFirstName("john"); user.setLastName("Maclane"); ResteasyClient client = new ResteasyClientBuilder().build(); ResteasyWebTarget target = client.target("http://localhost:8080/RESTEasyApplication/user-management/users"); Response response = target.request().post(Entity.entity(user, "application/vnd.com.demo.user-management.user+xml;charset=UTF-8;version=1")); //Read output in string format System.out.println(response.getStatus()); response.close(); } } Output in console: <?xml version="1.0" encoding="UTF-8" standalone="yes"?> <users> <user id="1" uri="/user-management/users/1"><firstName>demo</firstName><lastName>user</lastName></user> <user id="2" uri="/user-management/users/2"><firstName>demo</firstName><lastName>user</lastName></user> </users> 1 user 2 Dwain 201
Maven Configuration
I have used below Maven configuration to run these examples.
<repositories> <repository> <id>jboss</id> <url>https://repository.jboss.org/maven2/</url> </repository> </repositories> <dependencies> <dependency> <groupId>junit</groupId> <artifactId>junit</artifactId> <version>4.11</version> <scope>test</scope> </dependency> <!-- core library --> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-jaxrs</artifactId> <version>3.0.2.Final</version> </dependency> <!-- JAXB support --> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-jaxb-provider</artifactId> <version>3.0.2.Final</version> </dependency> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>jaxrs-api</artifactId> <version>3.0.2.Final</version> </dependency> <dependency> <groupId>org.jboss.resteasy</groupId> <artifactId>resteasy-client</artifactId> <version>3.0.2.Final</version> </dependency> <dependency> <groupId>net.sf.scannotation</groupId> <artifactId>scannotation</artifactId> <version>1.0.3</version> </dependency> </dependencies>
To download the source code of above example, follow below link.
Download sourcecode
Happy Learning !!