First commit of protocol buffers. (#452)

spring-protobuf/pom.xml

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+<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+	xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+	<modelVersion>4.0.0</modelVersion>
+	<groupId>com.baeldung</groupId>
+	<artifactId>spring-protobuf</artifactId>
+	<version>0.1-SNAPSHOT</version>
+	<name>spring-protobuf</name>
+
+	<parent>
+		<groupId>org.springframework.boot</groupId>
+		<artifactId>spring-boot-starter-parent</artifactId>
+		<version>1.2.4.RELEASE</version>
+	</parent>
+
+	<dependencies>
+		<dependency>
+			<groupId>com.google.protobuf</groupId>
+			<artifactId>protobuf-java</artifactId>
+			<version>3.0.0-beta-3</version>
+		</dependency>
+		<dependency>
+			<groupId>com.googlecode.protobuf-java-format</groupId>
+			<artifactId>protobuf-java-format</artifactId>
+			<version>1.4</version>
+		</dependency>
+
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-web</artifactId>
+		</dependency>
+		<dependency>
+			<groupId>org.springframework.boot</groupId>
+			<artifactId>spring-boot-starter-test</artifactId>
+			<scope>test</scope>
+		</dependency>
+
+		<dependency>
+			<groupId>org.apache.httpcomponents</groupId>
+			<artifactId>httpclient</artifactId>
+			<version>4.5.2</version>
+		</dependency>
+	</dependencies>
+</project>

spring-protobuf/src/main/java/com/baeldung/protobuf/Application.java

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+package com.baeldung.protobuf;
+
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+import org.springframework.context.annotation.Bean;
+import org.springframework.http.converter.protobuf.ProtobufHttpMessageConverter;
+import org.springframework.web.client.RestTemplate;
+
+import com.baeldung.protobuf.BaeldungTraining.Course;
+import com.baeldung.protobuf.BaeldungTraining.Student;
+import com.baeldung.protobuf.BaeldungTraining.Student.PhoneNumber;
+import com.baeldung.protobuf.BaeldungTraining.Student.PhoneType;
+
+@SpringBootApplication
+public class Application {
+    @Bean
+    RestTemplate restTemplate(ProtobufHttpMessageConverter hmc) {
+        return new RestTemplate(Arrays.asList(hmc));
+    }
+
+    @Bean
+    ProtobufHttpMessageConverter protobufHttpMessageConverter() {
+        return new ProtobufHttpMessageConverter();
+    }
+
+    @Bean
+    public CourseRepository createDummyCourses() {
+        Map<Integer, Course> dummy = new HashMap<>();
+        
+        Course course1 = Course.newBuilder().setId(1).setCourseName("REST with Spring").addAllStudent(createDummyStudents()).build();
+        Course course2 = Course.newBuilder().setId(2).setCourseName("Learn Spring Security").addAllStudent(new ArrayList<Student>()).build();
+        
+        dummy.put(course1.getId(), course1);
+        dummy.put(course2.getId(), course2);
+        
+        return new CourseRepository(dummy);
+    }
+
+    private List<Student> createDummyStudents() {
+        List<Student> studentList = new ArrayList<>();
+
+        PhoneNumber phone1 = createPhone("123456", PhoneType.MOBILE);
+        Student student1 = createStudent(1, "John", "Doe", "john.doe@baeldung.com", Arrays.asList(phone1));
+
+        PhoneNumber phone2 = createPhone("234567", PhoneType.LANDLINE);
+        Student student2 = createStudent(2, "Richard", "Roe", "richard.roe@baeldung.com", Arrays.asList(phone2));
+
+        PhoneNumber phone3_1 = createPhone("345678", PhoneType.MOBILE);
+        PhoneNumber phone3_2 = createPhone("456789", PhoneType.LANDLINE);
+        Student student3 = createStudent(3, "Jane", "Doe", "jane.doe@baeldung.com", Arrays.asList(phone3_1, phone3_2));
+
+        studentList.addAll(Arrays.asList(student1, student2, student3));
+        return studentList;
+    }
+
+    private Student createStudent(int id, String firstName, String lastName, String email, List<PhoneNumber> phones) {
+        return Student.newBuilder().setId(id).setFirstName(firstName).setLastName(lastName).setEmail(email).addAllPhone(phones).build();
+    }
+
+    private PhoneNumber createPhone(String number, PhoneType type) {
+        return PhoneNumber.newBuilder().setNumber(number).setType(type).build();
+    }
+}

spring-protobuf/src/main/java/com/baeldung/protobuf/CourseController.java

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+package com.baeldung.protobuf;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.baeldung.protobuf.BaeldungTraining.Course;
+
+@RestController
+public class CourseController {
+    @Autowired
+    CourseRepository courseRepo;
+
+    @RequestMapping("/courses/{id}")
+    Course customer(@PathVariable Integer id) {
+        return courseRepo.getCourse(id);
+    }
+}

spring-protobuf/src/main/java/com/baeldung/protobuf/CourseRepository.java

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+package com.baeldung.protobuf;
+
+import java.util.Map;
+
+import com.baeldung.protobuf.BaeldungTraining.Course;
+
+public class CourseRepository {
+    Map<Integer, Course> courses;
+    
+    public CourseRepository (Map<Integer, Course> courses) {
+        this.courses = courses;
+    }
+    
+    public Course getCourse(int id) {
+        return courses.get(id);
+    }
+}

spring-protobuf/src/main/resources/baeldung.proto

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+syntax = "proto3";
+
+package baeldung;
+
+option java_package = "com.baeldung.protobuf";
+option java_outer_classname = "BaeldungTraining";
+
+message Course {
+	int32 id = 1;
+	string course_name = 2;
+	repeated Student student = 3;
+}
+
+message Student {
+	int32 id = 1;
+	string first_name = 2;
+	string last_name = 3;
+	string email = 4;
+	repeated PhoneNumber phone = 5;
+
+	message PhoneNumber {
+		string number = 1;
+		PhoneType type = 2;
+	}
+
+	enum PhoneType {
+		MOBILE = 0;
+		LANDLINE = 1;
+	}
+}

spring-protobuf/src/test/java/com/baeldung/protobuf/ApplicationTest.java

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+package com.baeldung.protobuf;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+import org.apache.http.HttpResponse;
+import org.apache.http.client.methods.HttpGet;
+import org.apache.http.impl.client.CloseableHttpClient;
+import org.apache.http.impl.client.HttpClients;
+
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.boot.test.SpringApplicationConfiguration;
+import org.springframework.boot.test.WebIntegrationTest;
+import org.springframework.http.ResponseEntity;
+import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;
+import org.springframework.web.client.RestTemplate;
+
+import org.junit.Test;
+import org.junit.runner.RunWith;
+
+import com.baeldung.protobuf.BaeldungTraining.Course;
+import com.googlecode.protobuf.format.JsonFormat;
+
+import static org.junit.Assert.assertThat;
+import static org.hamcrest.CoreMatchers.containsString;
+
+@RunWith(SpringJUnit4ClassRunner.class)
+@SpringApplicationConfiguration(classes = Application.class)
+@WebIntegrationTest
+public class ApplicationTest {
+    private static final String COURSE1_URL = "http://localhost:8080/courses/1";
+    @Autowired
+    private RestTemplate restTemplate;
+
+    @Test
+    public void whenUsingRestTemplate_thenSucceed() {
+        ResponseEntity<Course> course = restTemplate.getForEntity(COURSE1_URL, Course.class);
+        assertResponse(course.toString());
+    }
+
+    @Test
+    public void whenUsingHttpClient_thenSucceed() throws IOException {
+        InputStream responseStream = executeHttpRequest(COURSE1_URL);
+        String jsonOutput = convertProtobufMessageStreamToJsonString(responseStream);
+        assertResponse(jsonOutput);
+    }
+
+    private InputStream executeHttpRequest(String url) throws IOException {
+        CloseableHttpClient httpClient = HttpClients.createDefault();
+        HttpGet request = new HttpGet(url);
+        HttpResponse httpResponse = httpClient.execute(request);
+        return httpResponse.getEntity().getContent();
+    }
+
+    private String convertProtobufMessageStreamToJsonString(InputStream protobufStream) throws IOException {
+        JsonFormat jsonFormat = new JsonFormat();
+        Course course = Course.parseFrom(protobufStream);
+        return jsonFormat.printToString(course);
+    }
+
+    private void assertResponse(String response) {
+        assertThat(response, containsString("id"));
+        assertThat(response, containsString("course_name"));
+        assertThat(response, containsString("REST with Spring"));
+        assertThat(response, containsString("student"));
+        assertThat(response, containsString("first_name"));
+        assertThat(response, containsString("last_name"));
+        assertThat(response, containsString("email"));
+        assertThat(response, containsString("john.doe@baeldung.com"));
+        assertThat(response, containsString("richard.roe@baeldung.com"));
+        assertThat(response, containsString("jane.doe@baeldung.com"));
+        assertThat(response, containsString("phone"));
+        assertThat(response, containsString("number"));
+        assertThat(response, containsString("type"));
+    }
+}