RESTful 資源：ContactsResource.java

package com.emprogria.rs.service; import com.emprogria.jpa.Contact; import java.util.Collection; import javax.ws.rs.Path; import javax.ws.rs.GET; import javax.ws.rs.POST; import javax.ws.rs.Produces; import javax.ws.rs.Consumes; import javax.ws.rs.PathParam; import javax.ws.rs.QueryParam; import javax.ws.rs.DefaultValue; import javax.ws.rs.core.Response; import javax.ws.rs.core.Context; import javax.ws.rs.core.UriInfo; import javax.persistence.EntityManager; import com.emprogria.rs.converter.ContactsConverter; import com.emprogria.rs.converter.ContactConverter; import com.sun.jersey.api.core.ResourceContext; import java.util.logging.Logger; @Path("/contacts/") public class ContactsResource { private Logger myLogger = Logger.getLogger("ContactsResource"); @Context protected ResourceContext resourceContext; @Context protected UriInfo uriInfo; /** Creates a new instance of ContactsResource */ public ContactsResource() { } /** * Get method for retrieving a collection of Contact instance in XML format. * * @return an instance of ContactsConverter */ @GET @Produces({"application/xml", "application/json"}) public ContactsConverter get(@QueryParam("start") @DefaultValue("0") int start, @QueryParam("max") @DefaultValue("10") int max, @QueryParam("expandLevel") @DefaultValue("1") int expandLevel, @QueryParam("query") @DefaultValue("SELECT e FROM Contact e") String query) { PersistenceService persistenceSvc = PersistenceService.getInstance(); ContactsConverter myContactsConverter = null; try { persistenceSvc.beginTx(); myContactsConverter = new ContactsConverter(getEntities(start, max, query), uriInfo.getAbsolutePath(), expandLevel); persistenceSvc.commitTx(); } catch (Exception ex) { persistenceSvc.rollbackTx(); this.myLogger.severe("GET:" + ex.getMessage()); } finally { persistenceSvc.close(); } return myContactsConverter; } /** * Post method for creating an instance of Contact using XML as the input format. * * @param data an ContactConverter entity that is deserialized from an XML stream * @return an instance of ContactConverter */ @POST @Consumes({"application/xml", "application/json"}) public Response post(ContactConverter data) { Response myResponse = null; PersistenceService persistenceSvc = PersistenceService.getInstance(); try { persistenceSvc.beginTx(); EntityManager em = persistenceSvc.getEntityManager(); Contact entity = data.resolveEntity(em); createEntity(data.resolveEntity(em)); persistenceSvc.commitTx(); myResponse = Response.created(uriInfo.getAbsolutePath().resolve(entity.getMsn() + "/")).build(); } catch (Exception ex) { persistenceSvc.rollbackTx(); this.myLogger.severe("POST:" + ex.getMessage()); } finally { persistenceSvc.close(); } return myResponse; } /** * Returns a dynamic instance of ContactResource used for entity navigation. * * @return an instance of ContactResource */ @Path("{msn}/") public ContactResource getContactResource(@PathParam("msn") String id) { ContactResource contactResource = resourceContext.getResource(ContactResource.class); contactResource.setId(id); return contactResource; } /** * Returns all the entities associated with this resource. * * @return a collection of Contact instances */ protected Collection<Contact> getEntities(int start, int max, String query) { EntityManager em = PersistenceService.getInstance().getEntityManager(); return em.createQuery(query).setFirstResult(start).setMaxResults(max).getResultList(); } /** * Persist the given entity. * * @param entity the entity to persist */ protected void createEntity(Contact entity) { EntityManager em = PersistenceService.getInstance().getEntityManager(); em.persist(entity); } }