Code examples for the 'Binary Data Formats in a Spring REST API'

article.

spring-rest/pom.xml

@@ -155,7 +155,16 @@
             <artifactId>spring-test</artifactId>
             <version>${spring.version}</version>
         </dependency>
-
+		<dependency>
+    		<groupId>com.google.protobuf</groupId>
+    		<artifactId>protobuf-java</artifactId>
+    		<version>2.6.1</version>
+		</dependency>
+		<dependency>
+    		<groupId>com.esotericsoftware.kryo</groupId>
+    		<artifactId>kryo</artifactId>
+    		<version>2.24.0</version>
+		</dependency>
     </dependencies>
 
     <build>

spring-rest/src/main/java/org/baeldung/config/WebConfig.java

@@ -3,11 +3,13 @@ package org.baeldung.config;
 import java.text.SimpleDateFormat;
 import java.util.List;
 
+import org.baeldung.config.converter.KryoHttpMessageConverter;
 import org.springframework.context.annotation.ComponentScan;
 import org.springframework.context.annotation.Configuration;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.json.Jackson2ObjectMapperBuilder;
 import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
+import org.springframework.http.converter.protobuf.ProtobufHttpMessageConverter;
 import org.springframework.http.converter.xml.MarshallingHttpMessageConverter;
 import org.springframework.oxm.xstream.XStreamMarshaller;
 import org.springframework.web.servlet.config.annotation.EnableWebMvc;
@@ -33,7 +35,8 @@ public class WebConfig extends WebMvcConfigurerAdapter {
         builder.indentOutput(true).dateFormat(new SimpleDateFormat("dd-MM-yyyy hh:mm"));
         messageConverters.add(new MappingJackson2HttpMessageConverter(builder.build()));
         // messageConverters.add(new MappingJackson2XmlHttpMessageConverter(builder.createXmlMapper(true).build()));
-
+        messageConverters.add(new ProtobufHttpMessageConverter());
+        messageConverters.add(new KryoHttpMessageConverter());
         super.configureMessageConverters(messageConverters);
     }
 

spring-rest/src/main/java/org/baeldung/config/converter/KryoHttpMessageConverter.java

@@ -0,0 +1,73 @@
+/*
+ * Copyright 2002-2014 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.baeldung.config.converter;
+
+import java.io.IOException;
+
+import org.baeldung.web.dto.Foo;
+import org.springframework.http.HttpInputMessage;
+import org.springframework.http.HttpOutputMessage;
+import org.springframework.http.MediaType;
+import org.springframework.http.converter.AbstractHttpMessageConverter;
+
+import com.esotericsoftware.kryo.Kryo;
+import com.esotericsoftware.kryo.io.Input;
+import com.esotericsoftware.kryo.io.Output;
+
+/**
+ * An {@code HttpMessageConverter} that can read and write Kryo messages.
+ */
+public class KryoHttpMessageConverter extends AbstractHttpMessageConverter<Object> {
+
+    public static final MediaType KRYO = new MediaType("application", "x-kryo");
+
+    private static final ThreadLocal<Kryo> kryoThreadLocal = new ThreadLocal<Kryo>() {
+        @Override
+        protected Kryo initialValue() {
+            final Kryo kryo = new Kryo();
+            kryo.register(Foo.class, 1);
+            return kryo;
+        }
+    };
+
+    public KryoHttpMessageConverter() {
+        super(KRYO);
+    }
+
+    @Override
+    protected boolean supports(final Class<?> clazz) {
+        return Object.class.isAssignableFrom(clazz);
+    }
+
+    @Override
+    protected Object readInternal(final Class<? extends Object> clazz, final HttpInputMessage inputMessage) throws IOException {
+        final Input input = new Input(inputMessage.getBody());
+        return kryoThreadLocal.get().readClassAndObject(input);
+    }
+
+    @Override
+    protected void writeInternal(final Object object, final HttpOutputMessage outputMessage) throws IOException {
+        final Output output = new Output(outputMessage.getBody());
+        kryoThreadLocal.get().writeClassAndObject(output, object);
+        output.flush();
+    }
+
+    @Override
+    protected MediaType getDefaultContentType(final Object object) {
+        return KRYO;
+    }
+}

spring-rest/src/main/java/org/baeldung/web/controller/FooController.java

@@ -4,6 +4,7 @@ import static org.apache.commons.lang3.RandomStringUtils.randomAlphabetic;
 import static org.apache.commons.lang3.RandomStringUtils.randomNumeric;
 
 import org.baeldung.web.dto.Foo;
+import org.baeldung.web.dto.FooProtos;
 import org.springframework.http.HttpStatus;
 import org.springframework.stereotype.Controller;
 import org.springframework.web.bind.annotation.PathVariable;
@@ -38,4 +39,9 @@ public class FooController {
         return foo;
     }
 
+    @RequestMapping(method = RequestMethod.GET, value = "/foos/{id}", produces = { "application/x-protobuf" })
+    @ResponseBody
+    public FooProtos.Foo findProtoById(@PathVariable final long id) {
+        return FooProtos.Foo.newBuilder().setId(1).setName("Foo Name").build();
+    }
 }

spring-rest/src/test/java/org/baeldung/web/test/SpringHttpMessageConvertersIntegrationTestsCase.java

@@ -7,7 +7,9 @@ import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 
+import org.baeldung.config.converter.KryoHttpMessageConverter;
 import org.baeldung.web.dto.Foo;
+import org.baeldung.web.dto.FooProtos;
 import org.junit.Assert;
 import org.junit.Test;
 import org.springframework.http.HttpEntity;
@@ -17,6 +19,7 @@ import org.springframework.http.MediaType;
 import org.springframework.http.ResponseEntity;
 import org.springframework.http.converter.HttpMessageConverter;
 import org.springframework.http.converter.json.MappingJackson2HttpMessageConverter;
+import org.springframework.http.converter.protobuf.ProtobufHttpMessageConverter;
 import org.springframework.http.converter.xml.MarshallingHttpMessageConverter;
 import org.springframework.oxm.xstream.XStreamMarshaller;
 import org.springframework.web.client.RestTemplate;
@@ -94,6 +97,38 @@ public class SpringHttpMessageConvertersIntegrationTestsCase {
         Assert.assertEquals(resource.getId(), fooResponse.getId());
     }
 
+    @Test
+    public void givenConsumingProtobuf_whenReadingTheFoo_thenCorrect() {
+        final String URI = BASE_URI + "foos/{id}";
+
+        final RestTemplate restTemplate = new RestTemplate();
+        restTemplate.setMessageConverters(Arrays.asList(new ProtobufHttpMessageConverter()));
+        final HttpHeaders headers = new HttpHeaders();
+        headers.setAccept(Arrays.asList(ProtobufHttpMessageConverter.PROTOBUF));
+        final HttpEntity<String> entity = new HttpEntity<String>(headers);
+
+        final ResponseEntity<FooProtos.Foo> response = restTemplate.exchange(URI, HttpMethod.GET, entity, FooProtos.Foo.class, "1");
+        final FooProtos.Foo resource = response.getBody();
+
+        assertThat(resource, notNullValue());
+    }
+
+    @Test
+    public void givenConsumingKryo_whenReadingTheFoo_thenCorrect() {
+        final String URI = BASE_URI + "foos/{id}";
+
+        final RestTemplate restTemplate = new RestTemplate();
+        restTemplate.setMessageConverters(Arrays.asList(new KryoHttpMessageConverter()));
+        final HttpHeaders headers = new HttpHeaders();
+        headers.setAccept(Arrays.asList(KryoHttpMessageConverter.KRYO));
+        final HttpEntity<String> entity = new HttpEntity<String>(headers);
+
+        final ResponseEntity<Foo> response = restTemplate.exchange(URI, HttpMethod.GET, entity, Foo.class, "1");
+        final Foo resource = response.getBody();
+
+        assertThat(resource, notNullValue());
+    }
+
     // UTIL
 
     private List<HttpMessageConverter<?>> getMessageConverters() {