juneau-rest-server
Maven Dependency

<dependency> <groupId>org.apache.juneau</groupId> <artifactId>juneau-rest-server</artifactId> <version>8.2.0</version> </dependency>

Java Library

juneau-rest-server-8.2.0.jar

OSGi Module

org.apache.juneau.rest.server_8.2.0.jar

The REST server API builds upon the SerializerGroup and ParserGroup classes to provide annotated REST servlets that automatically negotiate the HTTP media types for you. Developers simply work with requests, responses, headers, path variables, query parameters, and form data as POJOs. It allows you to create sophisticated REST interfaces using tiny amounts of code.

The end goal is to provide simple and flexible yet sophisticated REST interfaces that allow POJOs to be automatically represented as different content types depending on whatever the particular need:

A simple example that supports all languages:

@Rest( path="/systemProperties", title="System properties resource" ) public class SystemPropertiesResource extends BasicRestServlet { @RestMethod(name=GET, path="/") public Map getSystemProperties(@Query("sort") boolean sort) throws Throwable { if (sort) return new TreeMap(System.getProperties()); return System.getProperties(); } @RestMethod(name=GET, path="/{propertyName}") public String getSystemProperty(@Path("propertyName") String propertyName) throws Throwable { return System.getProperty(propertyName); } @RestMethod(name=PUT, path="/{propertyName}", guards=AdminGuard.class) public String setSystemProperty(@Path("propertyName") String propertyName, @Body String value) { System.setProperty(propertyName, value); return "OK"; } @RestMethod(name=POST, path="/", guards=AdminGuard.class) public String setSystemProperties(@Body java.util.Properties newProperties) { System.setProperties(newProperties); return "OK"; } @RestMethod(name=DELETE, path="/{propertyName}", guards=AdminGuard.class) public String deleteSystemProperty(@Path("propertyName") String propertyName) { System.clearProperty(propertyName); return "OK"; } }



The REST API is built on top of Servlets, making them easy to deploy in any JEE environment.

REST Java methods can return any of the following objects:
POJOs, @Response annotated objects, Readers, InputStreams, ZipFiles, Redirects, Streamables, and Writables.

Or add your own handlers for other types.

REST Java methods can be passed any of the following objects in any order:

Automatic error handling is provided for a variety of conditions:

Other features include:


Navigable hierarchies of REST resources are easy to set up either programmatically or through annotations.

The following example is the RootResources class from the REST examples showing how to construct a grouping of resources using the children() annotation:

@Rest( path="/", title="Root resources", description="Example of a router resource page.", children={ HelloWorldResource.class, PetStoreResource.class, DtoExamples.class, ConfigResource.class, LogsResource.class, ShutdownResource.class } ) @HtmlDocConfig( links={ "options: ?method=OPTIONS", "$W{ContentTypeMenuItem}", "source: $C{Source/gitHub}/org/apache/juneau/examples/rest/RootResources.java" }, aside={ "<div style='max-width:400px' class='text'>", " <p>This is an example of a 'router' page that serves as a jumping-off point to child resources.</p>", " <p>Resources can be nested arbitrarily deep through router pages.</p>", " <p>Note the options link provided that lets you see the generated swagger doc for this page.</p>", " <p>Also note the source link on these pages to view the source code for the page.</p>", " <p>All content on pages in the UI are serialized POJOs. In this case, it's a serialized array of beans with 2 properties, 'name' and 'description'.</p>", " <p>Other features (such as this aside) are added through annotations.</p>", "</div>" }, footer="$W{PoweredByApache}", widgets={ PoweredByApache.class, ContentTypeMenuItem.class } ) public class RootResources extends BasicRestServletGroup { /* No code needed! */ }

The above resource when rendered in HTML shows how easy it is to discover and navigate to child resources using a browser:

http://localhost:10000

Resources can be nested arbitrarily deep. The @Rest and @RestMethod annotations can be applied to any classes, not just servlets. The only requirement is that the top-level resource be a subclass of RestServlet as a hook into the servlet container.

The juneau-examples-rest project includes various other examples that highlight some of the capabilities of the REST servlet API.
For example, the PetStoreResource class shows some advanced features such as using POJO renders and converters, and HTML widgets.

http://localhost:10000/petstore

The beans being serialized are shown here:

// Our bean class. public class Pet { @Html(link="servlet:/{id}") // Creates a hyperlink in HTML view. @NameProperty // Links the parent key to this bean. public int id; public String name; public Kind kind; @Beanp(format="$%.2f") // Renders price in dollars. public float price; @Beanp(swap=DateSwap.RFC2822D.class) // Renders dates in RFC2822 format. public Date birthDate; public int getAge() { Calendar calendar = new GregorianCalendar(); calendar.setTime(birthDate); return new GregorianCalendar().get(Calendar.YEAR) - calendar.get(Calendar.YEAR); } } @Html(render=KindRender.class) // Render as an icon in HTML. public static enum Kind { CAT, DOG, BIRD, FISH, MOUSE, RABBIT, SNAKE } public static class KindRender extends HtmlRender<Kind> { @Override public Object getContent(SerializerSession session, Kind value) { return new Img().src("servlet:/htdocs/"+value.toString().toLowerCase()+".png"); } @Override public String getStyle(SerializerSession session, Kind value) { return "background-color:#FDF2E9"; } }

The QUERY menu item shows the capabilities of Converters which are post-processors that work to filter POJOs after they've been returned by your Java method.
In this case, we're using the Queryable converter that allows us to perform search/view/sort/paging against collections of beans:

The drop-down menu items are implemented through "widgets" which allow you to embed arbitrary HTML, Javascript, and CSS in the HTML view of the page.

@RestMethod( name=GET, path="/", summary="The complete list of pets in the store", // Add our converter for POJO query support. converters=Queryable.class ) @HtmlDocConfig( // Add our menu items in the nav links. links={ "up: request:/..", "options: servlet:/?method=OPTIONS", "$W{QueryMenuItem}", "$W{ContentTypeMenuItem}", "$W{StyleMenuItem}", "source: $C{Source/gitHub}/org/apache/juneau/examples/rest/PetStoreResource.java" }, // Add 'query' and 'content-types' menu items. widgets={ QueryMenuItem.class, ContentTypeMenuItem.class, StyleMenuItem.class } ) public Collection<Pet> getPets() {

HTML views are highly customizable with abilities such as defining your own look-and-feel and even allowing you to define your own templates.

For example, the PetStore page above rendered in one of the other predefined stylesheets:

Light look-and-feel
Dark look-and-feel

Swagger UI is auto-generated and self-hosted through OPTIONS requests:

http://localhost:10000/petstore?method=OPTIONS



Swagger contains auto-generated code examples for all supported languages:


juneau-rest-server-springboot
Maven Dependency

<dependency> <groupId>org.apache.juneau</groupId> <artifactId>juneau-rest-server-springboot</artifactId> <version>8.2.0</version> </dependency>

Java Library

juneau-rest-server-springboot-8.2.0.jar

OSGi Module

org.apache.juneau.rest.server.springboot_8.2.0.jar

The juneau-rest-server-springboot library provides classes to make it easy to integrate Juneau REST resources with Spring and Spring Boot.

Example:

@SpringBootApplication @Controller public class App { public static void main(String[] args) { new SpringApplicationBuilder(App.class) .initializers(new JuneauRestInitializer(App.class)) .run(args); } /** Our root resource */ @Bean @JuneauRestRoot public RootResource getRootResource() { return new RootResource(); // A subclass of RestServlet. } }

The initializer will search for Spring beans annotated with the @JuneauRestRoot annotation identifying it as a top-level servlet to be deployed in the Spring Boot web container.

juneau-rest-server-jaxrs
Maven Dependency

<dependency> <groupId>org.apache.juneau</groupId> <artifactId>juneau-rest-server-jaxrs</artifactId> <version>8.2.0</version> </dependency>

Java Library

juneau-rest-server-jaxrs-8.2.0.jar

OSGi Module

org.apache.juneau.rest.server.jaxrs_8.2.0.jar

The juneau-rest-server-jaxrs module defines predefined MessageBodyReader and MessageBodyWriter implementations for using Juneau serializers and parsers in JAX-RS environments.