#202 - Added example for JSONPath and XPath based payload binding to projection interfaces.

See the readme for details.

web/projection/src/main/java/example/users/Application.java

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+/*
+ * Copyright 2015 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 example.users;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+/**
+ * @author Oliver Gierke
+ */
+@SpringBootApplication
+public class Application {
+
+	public static void main(String[] args) {
+		SpringApplication.run(Application.class, args);
+	}
+}

web/projection/src/main/java/example/users/UserController.java

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+/*
+ * Copyright 2015-2016 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 example.users;
+
+import java.util.Collections;
+import java.util.HashMap;
+import java.util.Map;
+
+import org.springframework.data.web.JsonPath;
+import org.springframework.data.web.ProjectedPayload;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.MediaType;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RestController;
+import org.xmlbeam.annotation.XBRead;
+
+/**
+ * Controller to handle web requests for {@link UserPayload}s.
+ * 
+ * @author Oliver Gierke
+ */
+@RestController
+class UserController {
+
+	private static String XML_PAYLOAD = "<firstname>Dave</firstname><lastname>Matthews</lastname>";
+
+	/**
+	 * Receiving POST requests supporting both JSON and XML.
+	 * 
+	 * @param user
+	 * @return
+	 */
+	@PostMapping(value = "/")
+	HttpEntity<String> post(@RequestBody UserPayload user) {
+
+		return ResponseEntity
+				.ok(String.format("Received firstname: %s, lastname: %s", user.getFirstname(), user.getLastname()));
+	}
+
+	/**
+	 * Returns a simple JSON payload.
+	 * 
+	 * @return
+	 */
+	@GetMapping(path = "/", produces = MediaType.APPLICATION_JSON_VALUE)
+	Map<String, Object> getJson() {
+
+		Map<String, Object> result = new HashMap<>();
+		result.put("firstname", "Dave");
+		result.put("lastname", "Matthews");
+
+		return result;
+	}
+
+	/**
+	 * Returns the payload of {@link #getJson()} wrapped into another element to simulate a change in the representation.
+	 * 
+	 * @return
+	 */
+	@GetMapping(path = "/changed", produces = MediaType.APPLICATION_JSON_VALUE)
+	Map<String, Object> getChangedJson() {
+		return Collections.singletonMap("user", getJson());
+	}
+
+	/**
+	 * Returns a simple XML payload.
+	 * 
+	 * @return
+	 */
+	@GetMapping(path = "/", produces = MediaType.APPLICATION_XML_VALUE)
+	String getXml() {
+		return "<user>".concat(XML_PAYLOAD).concat("</user>");
+	}
+
+	/**
+	 * Returns the payload of {@link #getXml()} wrapped into another XML element to simulate a change in the
+	 * representation structure.
+	 * 
+	 * @return
+	 */
+	@GetMapping(path = "/changed", produces = MediaType.APPLICATION_XML_VALUE)
+	String getChangedXml() {
+		return "<user><username>".concat(XML_PAYLOAD).concat("</username></user>");
+	}
+
+	/**
+	 * The projection interface using XPath and JSON Path expression to selectively pick elements from the payload.
+	 *
+	 * @author Oliver Gierke
+	 */
+	@ProjectedPayload
+	public interface UserPayload {
+
+		@XBRead("//firstname")
+		@JsonPath("$..firstname")
+		String getFirstname();
+
+		@XBRead("//lastname")
+		@JsonPath("$..lastname")
+		String getLastname();
+	}
+}

web/projection/src/main/resources/application.properties

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+logging.level.org.springframework.web=DEBUG
+logging.level.org.springframework.boot=DEBUG

web/projection/src/test/java/example/users/UserControllerClientTests.java

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+/*
+ * Copyright 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 example.users;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.junit.Assert.*;
+
+import example.users.UserController.UserPayload;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.boot.test.context.SpringBootTest.WebEnvironment;
+import org.springframework.boot.test.web.client.TestRestTemplate;
+import org.springframework.boot.web.client.RestTemplateBuilder;
+import org.springframework.context.annotation.Bean;
+import org.springframework.context.annotation.Configuration;
+import org.springframework.context.annotation.Import;
+import org.springframework.data.web.ProjectingJackson2HttpMessageConverter;
+import org.springframework.data.web.XmlBeamHttpMessageConverter;
+import org.springframework.http.HttpEntity;
+import org.springframework.http.HttpHeaders;
+import org.springframework.http.HttpMethod;
+import org.springframework.http.MediaType;
+import org.springframework.http.converter.HttpMessageConverter;
+import org.springframework.test.context.junit4.SpringRunner;
+
+/**
+ * Integration tests for {@link UserController} to demonstrate client-side resilience of the payload type against
+ * changes in the representation.
+ * 
+ * @author Oliver Gierke
+ */
+@RunWith(SpringRunner.class)
+@SpringBootTest(webEnvironment = WebEnvironment.RANDOM_PORT)
+public class UserControllerClientTests {
+
+	@Autowired TestRestTemplate template;
+
+	/**
+	 * Custom configuration for the test to enrich the {@link TestRestTemplate} with the {@link HttpMessageConverter}s for
+	 * XML and JSON projections.
+	 *
+	 * @author Oliver Gierke
+	 */
+	@Configuration
+	@Import(Application.class)
+	static class Config {
+
+		@Bean
+		RestTemplateBuilder builder() {
+			return new RestTemplateBuilder()//
+					.additionalMessageConverters(new ProjectingJackson2HttpMessageConverter())//
+					.additionalMessageConverters(new XmlBeamHttpMessageConverter());
+		}
+	}
+
+	@Test
+	public void accessJsonFieldsOnSimplePayload() {
+		assertDave(issueGet("/", MediaType.APPLICATION_JSON));
+	}
+
+	@Test
+	public void accessJsonFieldsOnNestedPayload() {
+		assertDave(issueGet("/changed", MediaType.APPLICATION_JSON));
+	}
+
+	@Test
+	public void accessXmlElementsOnSimplePayload() {
+		assertDave(issueGet("/", MediaType.APPLICATION_XML));
+	}
+
+	@Test
+	public void accessXmlElementsOnNestedPayload() {
+		assertDave(issueGet("/changed", MediaType.APPLICATION_XML));
+	}
+
+	private UserPayload issueGet(String path, MediaType mediaType) {
+
+		HttpHeaders headers = new HttpHeaders();
+		headers.add(HttpHeaders.ACCEPT, mediaType.toString());
+
+		return template.exchange(path, HttpMethod.GET, new HttpEntity<Void>(headers), UserPayload.class).getBody();
+	}
+
+	private static void assertDave(UserPayload payload) {
+
+		assertThat(payload.getFirstname(), is("Dave"));
+		assertThat(payload.getLastname(), is("Matthews"));
+	}
+}

web/projection/src/test/java/example/users/UserControllerIntegrationTests.java

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+/*
+ * Copyright 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 example.users;
+
+import static org.hamcrest.CoreMatchers.*;
+import static org.springframework.test.web.servlet.request.MockMvcRequestBuilders.*;
+import static org.springframework.test.web.servlet.result.MockMvcResultMatchers.*;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.autoconfigure.web.servlet.AutoConfigureMockMvc;
+import org.springframework.boot.test.context.SpringBootTest;
+import org.springframework.http.MediaType;
+import org.springframework.test.context.junit4.SpringRunner;
+import org.springframework.test.web.servlet.MockMvc;
+import org.springframework.test.web.servlet.ResultActions;
+
+/**
+ * Integration tests for {@link UserController}.
+ * 
+ * @author Oliver Gierke
+ */
+@RunWith(SpringRunner.class)
+@SpringBootTest
+@AutoConfigureMockMvc(alwaysPrint = false)
+public class UserControllerIntegrationTests {
+
+	@Autowired MockMvc mvc;
+
+	@Test
+	public void handlesJsonPayloadWithExactProperties() throws Exception {
+		postAndExpect("{ \"firstname\" : \"Dave\", \"lastname\" : \"Matthews\" }", MediaType.APPLICATION_JSON);
+	}
+
+	@Test
+	public void handlesJsonPayloadWithNestedProperties() throws Exception {
+		postAndExpect("{ \"user\" : { \"firstname\" : \"Dave\", \"lastname\" : \"Matthews\" } }",
+				MediaType.APPLICATION_JSON);
+	}
+
+	@Test
+	public void handlesXmlPayLoadWithExactProperties() throws Exception {
+
+		postAndExpect("<user><firstname>Dave</firstname><lastname>Matthews</lastname></user>", MediaType.APPLICATION_XML);
+	}
+
+	private void postAndExpect(String payload, MediaType mediaType) throws Exception {
+
+		ResultActions actions = mvc
+				.perform(post("/")//
+						.content(payload)//
+						.contentType(mediaType))//
+				.andExpect(status().isOk());
+
+		actions.andExpect(content().string(containsString("Dave")));
+		actions.andExpect(content().string(containsString("Matthews")));
+	}
+}