This is sample of using EverRest to launch JAX-RS services.
We will create simple books service. It should be able give access to books by id, get list all available books and add new book in storage. Service supports JSON format for transfer data to/from client.
<context-param>
<param-name>javax.ws.rs.Application</param-name>
<param-value>org.everrest.sample.book.BookApplication</param-value>
</context-param>
javax.ws.rs.Application
: This is FQN of Java class that extends javax.ws.rs.core.Application and provides set of classes and(or) instances of JAX-RS components.
Need add two listeners. First one initializes BookStorage and adds it to servlet context. The second one initializes common components of EverRest frameworks.
<listener>
<listener-class>org.everrest.sample.book.BookServiceBootstrap</listener-class>
</listener>
<listener>
<listener-class>org.everrest.core.servlet.EverrestInitializedListener</listener-class>
</listener>
<servlet>
<servlet-name>EverrestServlet</servlet-name>
<servlet-class>org.everrest.core.servlet.EverrestServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>EverrestServlet</servlet-name>
<url-pattern>/*</url-pattern>
</servlet-mapping>
-
org.everrest.sample.book.BookApplication
- application deployer.public class BookApplication extends Application { @Override public Set<Class<?>> getClasses() { Set<Class<?>> cls = new HashSet<Class<?>>(1); cls.add(BookService.class); return cls; } @Override public Set<Object> getSingletons() { Set<Object> objs = new HashSet<Object>(1); objs.add(new BookNotFoundExceptionMapper()); return objs; } }
-
org.everrest.sample.book.Book
- simple Java Bean that will be used to transfer data via JSON. -
org.everrest.sample.book.BookNotFoundException
- exception that will be thrown byorg.everrest.sample.book.BookService
if client requested book that does not exist in storage. -
org.everrest.sample.book.BookNotFoundExceptionMapper
- JAX-RS component that interceptsorg.everrest.sample.book.BookNotFoundException
and send correct response to client.@Provider public class BookNotFoundExceptionMapper implements ExceptionMapper<BookNotFoundException> { Response toResponse(BookNotFoundException exception) { return Response.status(404).entity(exception.getMessage()).type("text/plain").build(); } }
-
org.everrest.sample.book.BookService
- JAX-RS service that process client's requests. Instance of BookStorage will be injected automatically thanks toorg.everrest.core.Inject
annotation@Path("books") public class BookService { @Inject private BookStorage bookStorage; @Path("{id}") @GET @Produces("application/json") public Book get(@PathParam("id") String id) throws BookNotFoundException { Book book = bookStorage.getBook(id); if (book == null) throw new BookNotFoundException(id); return book; } @GET @Produces("application/json") public Collection<Book> getAll() { return bookStorage.getAll(); } @PUT @Consumes("application/json") public Response put(Book book, @Context UriInfo uriInfo) { String id = bookStorage.putBook(book); URI location = uriInfo.getBaseUriBuilder().path(getClass()).path(id).build(); return Response.created(location).entity(location.toString()).type("text/plain").build(); } }
-
org.everrest.sample.book.BookStorage
- storage of Books.public class BookStorage { private static int idCounter = 100; public synchronized String generateId() { idCounter++; return Integer.toString(idCounter); } private Map<String, Book> books = new ConcurrentHashMap<String, Book>(); public BookStorage() { init(); } private void init() { Book book = new Book(); book.setTitle("JUnit in Action"); book.setAuthor("Vincent Masson"); book.setPages(386); book.setPrice(19.37); putBook(book); } public Book getBook(String id) { return books.get(id); } public String putBook(Book book) { String id = book.getId(); if (id == null || id.trim().length() == 0) { id = generateId(); book.setId(id); } books.put(id, book); return id; } public Collection<Book> getAll() { return books.values(); } public int numberOfBooks() { return books.size(); } }
- GET
book-service/books/{id}
: get books with specified id. Just after server start only one book in storage and it can be accessed via id101
- GET
book-service/books/
: get all books from storage. - PUT
book-service/books/
: add new book in storage. The body of request must contains book's description in JSON format. TheContent-type
header must be set toapplication/json
Build project.
mvn clean install
Run it with Jetty server.
mvn jetty:run
Point you web browser to http://localhost:8080/book-service/books/101
If you are under linux or other unix like OS the you can use curl
utility (often it is already installed). Binary build of this utility available for windows also at http://curl.haxx.se/download.html. With curl
you able to add new book in storage via command:
curl -X PUT \
-H "Content-type:application/json" \
-d '{"author":"My Author","title":"My Title","price":1.00,"pages":100}' \
http://localhost:8080/book-service/books/