simplify content negotiation setup

- remove custom xml view, use springboot builtin xml view
- remove oxm maven dependency
- remove json-simple maven dependency (seems not relevant anymore)
- update vetsXml test using xpath

src/main/java/org/springframework/samples/petclinic/PetClinicApplication.java

@@ -16,36 +16,16 @@
 
 package org.springframework.samples.petclinic;
 
-import com.github.dandelion.core.web.DandelionFilter;
-import com.github.dandelion.core.web.DandelionServlet;
-import net.sf.ehcache.config.CacheConfiguration;
-import net.sf.ehcache.config.PersistenceConfiguration;
-import net.sf.ehcache.config.PersistenceConfiguration.Strategy;
-import net.sf.ehcache.store.MemoryStoreEvictionPolicy;
 import org.springframework.boot.SpringApplication;
-import org.springframework.boot.autoconfigure.EnableAutoConfiguration;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
 import org.springframework.boot.builder.SpringApplicationBuilder;
-import org.springframework.boot.context.embedded.FilterRegistrationBean;
-import org.springframework.boot.context.embedded.ServletRegistrationBean;
 import org.springframework.boot.context.web.SpringBootServletInitializer;
-import org.springframework.cache.CacheManager;
-import org.springframework.cache.annotation.CachingConfigurerSupport;
-import org.springframework.cache.annotation.EnableCaching;
-import org.springframework.cache.ehcache.EhCacheCacheManager;
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.ComponentScan;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.oxm.jaxb.Jaxb2Marshaller;
-import org.springframework.samples.petclinic.model.Vets;
-import org.springframework.web.servlet.view.xml.MarshallingView;
 
 /**
  * PetClinic Spring Boot Application.
  *
  */
-@Configuration
-@EnableAutoConfiguration
-@ComponentScan
+@SpringBootApplication
 public class PetClinicApplication extends SpringBootServletInitializer {
 
     @Override

src/main/java/org/springframework/samples/petclinic/config/CustomViewsConfiguration.java

@@ -1,42 +0,0 @@
-/*
- * Copyright 2002-2016 the original author or authors.
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.springframework.samples.petclinic.config;
-
-import org.springframework.context.annotation.Bean;
-import org.springframework.context.annotation.Configuration;
-import org.springframework.oxm.jaxb.Jaxb2Marshaller;
-import org.springframework.samples.petclinic.model.Vets;
-import org.springframework.web.servlet.view.BeanNameViewResolver;
-import org.springframework.web.servlet.view.xml.MarshallingView;
-
-/**
- *
- * {@link BeanNameViewResolver} is used to resolve the Atom and Xml views. So, the
- * following beans names must match the name of the JSP you want to override and the
- * file extension will indicate which bean to use for resolving.
- *
- */
-@Configuration
-public class CustomViewsConfiguration {
-
-	@Bean(name = "vets/vetList.xml")
-	public MarshallingView vetsXmlView() {
-		Jaxb2Marshaller marshaller = new Jaxb2Marshaller();
-		marshaller.setClassesToBeBound(Vets.class);
-		return new MarshallingView(marshaller);
-	}
-}

src/main/java/org/springframework/samples/petclinic/web/VetController.java

@@ -18,6 +18,7 @@ package org.springframework.samples.petclinic.web;
 import java.util.Map;
 
 import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.http.MediaType;
 import org.springframework.samples.petclinic.model.Vets;
 import org.springframework.samples.petclinic.service.ClinicService;
 import org.springframework.stereotype.Controller;
@@ -41,7 +42,7 @@ public class VetController {
         this.clinicService = clinicService;
     }
 
-    @RequestMapping(value = {"/vets.xml", "/vets.html"})
+    @RequestMapping(value = {"/vets.html"})
     public String showVetList(Map<String, Object> model) {
         // Here we are returning an object of type 'Vets' rather than a collection of Vet objects
         // so it is simpler for Object-Xml mapping
@@ -51,7 +52,7 @@ public class VetController {
         return "vets/vetList";
     }
 
-    @RequestMapping("/vets.json")
+    @RequestMapping(value = {"/vets.json", "/vets.xml"})
     public
     @ResponseBody
     Vets showResourcesVetList() {