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MediaType.APPLICATION_XML and MediaType.APPLICATION_JSON in a Jersey demo application

As soon as I received this question. The last example of Jersey did not answer, I ran into another curious problem:

Server GET methods work fine. I tested and added some test code for the helloworld-pure-jax-rs example and esp. Added POST request for JSON:

package org.glassfish.jersey.examples.helloworld.jaxrs; import javax.ws.rs.Consumes; import javax.ws.rs.GET; import javax.ws.rs.POST; import javax.ws.rs.Path; import javax.ws.rs.PathParam; import javax.ws.rs.Produces; import javax.ws.rs.core.MediaType; import javax.ws.rs.core.Response; @Path("helloworld") public class HelloWorldResource { public static final String CLICHED_MESSAGE = "Hello World!"; @GET @Produces(MediaType.TEXT_PLAIN) public String getHello() { return CLICHED_MESSAGE; } @GET @Produces(MediaType.APPLICATION_JSON) public String getHelloJson() { return "{ \"message\":" + CLICHED_MESSAGE + "}"; } @GET @Produces(MediaType.TEXT_HTML) public String getHelloHtml() { return "<html> " + "<title>" + "Hello Jersey" + "</title>" + "<body><h1>" + CLICHED_MESSAGE + "</body></h1>" + "</html> "; } @GET @Produces(MediaType.TEXT_PLAIN) @Path("/v2") public String getHello2() { return CLICHED_MESSAGE + " v2"; } @GET @Produces(MediaType.TEXT_PLAIN) @Path("/{id}") public String getHelloId(@PathParam("id") String id) { return CLICHED_MESSAGE + " Parameter: " + id; } @GET @Produces(MediaType.TEXT_PLAIN) @Path("/id/{id : [a-zA-Z][a-zA-Z_0-9]}") public String getHelloIdId(@PathParam("id") String id) { return CLICHED_MESSAGE + " Parameter: " + id; } @POST @Consumes(MediaType.TEXT_PLAIN) @Produces(MediaType.TEXT_PLAIN) public Response test(String test) { if (test.equals("test")) return Response.status(400).entity("Error: " + test).build(); return Response.status(200).entity(test).build(); } @POST @Path("/test") @Consumes(MediaType.APPLICATION_JSON) @Produces(MediaType.APPLICATION_JSON) public Response testJSON(Test test) { String result = "Test JSON created : " + test.getName() + "" + test.getAge(); // return result; return Response.status(200).entity(result).build(); } @POST @Path("/test") @Consumes(MediaType.APPLICATION_XML) @Produces(MediaType.APPLICATION_XML) public Response testXML(Test test) { String result = "Test XML created : " + test.getName() + "" + test.getAge(); // return result; return Response.status(200).entity(result).build(); } }

Here are the rest of the classes:

 package org.glassfish.jersey.examples.helloworld.jaxrs; import java.io.IOException; import java.net.InetSocketAddress; import java.net.URI; import javax.ws.rs.core.UriBuilder; import javax.ws.rs.ext.RuntimeDelegate; import com.sun.net.httpserver.HttpHandler; import com.sun.net.httpserver.HttpServer; /** * Hello world application using only the standard JAX-RS API and lightweight * HTTP server bundled in JDK. * * @author Martin Matula (martin.matula at oracle.com) */ @SuppressWarnings("restriction") public class App { /** * Starts the lightweight HTTP server serving the JAX-RS application. * * @return new instance of the lightweight HTTP server * @throws IOException */ static HttpServer startServer() throws IOException { // create a new server listening at port 8080 HttpServer server = HttpServer.create(new InetSocketAddress(getBaseURI().getPort()), 0); // create a handler wrapping the JAX-RS application HttpHandler handler = RuntimeDelegate.getInstance().createEndpoint(new JaxRsApplication(), HttpHandler.class); // map JAX-RS handler to the server root server.createContext(getBaseURI().getPath(), handler); // start the server server.start(); return server; } public static void main(String[] args) throws IOException { System.out.println("\"Hello World\" Jersey Example Application"); HttpServer server = startServer(); System.out.println("Application started.\n" + "Try accessing " + getBaseURI() + "helloworld in the browser.\n" + "Hit enter to stop the application..."); System.in.read(); server.stop(0); } private static int getPort(int defaultPort) { final String port = System.getProperty("jersey.config.test.container.port"); if (null != port) { try { return Integer.parseInt(port); } catch (NumberFormatException e) { System.out.println("Value of jersey.config.test.container.port property" + " is not a valid positive integer [" + port + "]." + " Reverting to default [" + defaultPort + "]."); } } return defaultPort; } /** * Gets base {@link URI}. * * @return base {@link URI}. */ public static URI getBaseURI() { return UriBuilder.fromUri("http://localhost/").port(getPort(8080)).build(); } } public class Test { public int age = 0; public String name = ""; /** * */ public Test() { super(); } /** * @param age */ public Test(int age) { super(); this.age = age; } /** * @param name */ public Test(String name) { super(); this.name = name; } /** * @param name * @param age */ public Test(String name, int age) { super(); this.name = name; this.age = age; } public int getAge() { return age; } public String getName() { return name; } public void setAge(int age) { this.age = age; } public void setName(String name) { this.name = name; } } package org.glassfish.jersey.examples.helloworld.jaxrs; import java.util.Collections; import java.util.HashSet; import java.util.Set; import javax.ws.rs.core.Application; public class JaxRsApplication extends Application { private final Set<Class<?>> classes; public JaxRsApplication() { HashSet<Class<?>> c = new HashSet<Class<?>>(); c.add(HelloWorldResource.class); classes = Collections.unmodifiableSet(c); } @Override public Set<Class<?>> getClasses() { return classes; } }

This works great for plain text messages, but fpr for json (MediaType.APPLICATION_JSON) and xml (MediaType.APPLICATION_XML) cannot specify an unsupported media type. Any idea what could be wrong?

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1 answer

JAX-RS has a bunch of built-in handlers that can marshal from several different specific Java types.

As soon as we start working with custom data binding (marshalling / unmarshalling to Java objects), we are in another ball game. Now we need another MessageBodyWriters and MesageBodyReaders .

Fortunately, there are already readers and writers for binding XML and JSON data. JAX-RS comes with standard XML marshalling / unmarshalling with one warning. We must use JAXB annotations. So, for your Test class, assuming it looks like

 public class Test { private String name; private int age; public String getName() { return name; } public void setName(String name) { this.name = name;} public int getAge() { return age; } public void setAge(int age) { this.age = age; } }

in order to enable the JAXB provider unmarshall / marshall, we must provide at least @XmlRootElement

 @XmlRootElement public class Test { .... }

Doing this should enable XML to work.

As for JSON, JSON binding is not a standard specification parameter, but we can simply add a dependency on the project, which will automatically register the necessary provider to handle the JSON binding. You can look at pom.xml for a json-moxy example . You will see this necessary dependency.

 <dependency> <groupId>org.glassfish.jersey.media</groupId> <artifactId>jersey-media-moxy</artifactId> </dependency>

The dependency that the application allows you to do is marshal / unmarshal jSON for / from our Java objects using JAXB annotations. Therefore, simply adding this dependency to pom.xml . The application should work. Just tested.

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Source: https://habr.com/ru/post/977602/

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