プロトコルバッファを含むSpring REST API

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;
    }
}

protoc --java__out=java resources/baeldung.proto

<dependency>
    <groupId>com.google.protobuf</groupId>
    <artifactId>protobuf-java</artifactId>
    <version>3.0.0-beta-3</version>
</dependency>

public int getId();
public java.lang.String getCourseName();

public java.util.List<com.baeldung.protobuf.BaeldungTraining.Student> getStudentList();
public int getStudentCount();
public com.baeldung.protobuf.BaeldungTraining.Student getStudent(int index);

public int getId();
public java.lang.String getFirstName();
public java.lang.String getLastName();
public java.lang.String.getEmail();

public java.util.List<com.baeldung.protobuf.BaeldungTraining.Student.PhoneNumber> getPhoneList();
public int getPhoneCount();
public com.baeldung.protobuf.BaeldungTraining.Student.PhoneNumber getPhone(int index);

public java.lang.String getNumber();
public com.baeldung.protobuf.BaeldungTraining.Student.PhoneType getType();

public enum PhoneType implements com.google.protobuf.ProtocolMessageEnum {
    MOBILE(0),
    LANDLINE(1),
    UNRECOGNIZED(-1),
    ;
   //Other declarations
}

@SpringBootApplication
public class Application {
    @Bean
    ProtobufHttpMessageConverter protobufHttpMessageConverter() {
        return new ProtobufHttpMessageConverter();
    }

    @Bean
    public CourseRepository createTestCourses() {
        Map<Integer, Course> courses = new HashMap<>();
        Course course1 = Course.newBuilder()
          .setId(1)
          .setCourseName("REST with Spring")
          .addAllStudent(createTestStudents())
          .build();
        Course course2 = Course.newBuilder()
          .setId(2)
          .setCourseName("Learn Spring Security")
          .addAllStudent(new ArrayList<Student>())
          .build();
        courses.put(course1.getId(), course1);
        courses.put(course2.getId(), course2);
        return new CourseRepository(courses);
    }

   //Other declarations
}

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);
    }
}

@RestController
public class CourseController {
    @Autowired
    CourseRepository courseRepo;

    @RequestMapping("/courses/{id}")
    Course customer(@PathVariable Integer id) {
        return courseRepo.getCourse(id);
    }
}

private static final String COURSE1__URL = "http://localhost:8080/courses/1";

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("[email protected]"));
    assertThat(response, containsString("[email protected]"));
    assertThat(response, containsString("[email protected]"));
    assertThat(response, containsString("phone"));
    assertThat(response, containsString("number"));
    assertThat(response, containsString("type"));
}

@Autowired
private RestTemplate restTemplate;

@Test
public void whenUsingRestTemplate__thenSucceed() {
    ResponseEntity<Course> course = restTemplate.getForEntity(COURSE1__URL, Course.class);
    assertResponse(course.toString());
}

@Bean
RestTemplate restTemplate(ProtobufHttpMessageConverter hmc) {
    return new RestTemplate(Arrays.asList(hmc));
}

<dependency>
    <groupId>com.googlecode.protobuf-java-format</groupId>
    <artifactId>protobuf-java-format</artifactId>
    <version>1.4</version>
</dependency>
<dependency>
    <groupId>org.apache.httpcomponents</groupId>
    <artifactId>httpclient</artifactId>
    <version>4.5.2</version>
</dependency>

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);
}

@Test
public void whenUsingHttpClient__thenSucceed() throws IOException {
    InputStream responseStream = executeHttpRequest(COURSE1__URL);
    String jsonOutput = convertProtobufMessageStreamToJsonString(responseStream);
    assertResponse(jsonOutput);
}

id: 1
course__name: "REST with Spring"
student {
    id: 1
    first__name: "John"
    last__name: "Doe"
    email: "[email protected]"
    phone {
        number: "123456"
    }
}
student {
    id: 2
    first__name: "Richard"
    last__name: "Roe"
    email: "[email protected]"
    phone {
        number: "234567"
        type: LANDLINE
    }
}
student {
    id: 3
    first__name: "Jane"
    last__name: "Doe"
    email: "[email protected]"
    phone {
        number: "345678"
    }
    phone {
        number: "456789"
        type: LANDLINE
    }
}