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Spring Boot 기반 back-end 개발

1. Spring Initializr

http://start.spring.io 접속
프로젝트 생성
- Project : Maven Project
- Language : Java
- Spring Boot : 2.1.3
- Project Metadata
  - Group : com.samsungsds.backend
  - Artifact : stock
- Dependencies : Web
프로젝트 압축 해제
프로젝트 Import

2. pom.xml 설정 (proxy)

<repositories>
    <repository>
        <id>public-repository</id>
        <url>http://70.121.224.52:8081/nexus/content/groups/public</url>
    </repository>
</repositories>
 
<pluginRepositories>
    <pluginRepository>
        <id>public-repository</id>
        <url>http://70.121.224.52:8081/nexus/content/groups/public</url>
    </pluginRepository>
</pluginRepositories>

3. controller 패키지 생성, HelloController 클래스 생성

@RestController
public class HelloController {
 
    @RequestMapping("/hello")
    public String index() {
        return "hello world!";
    }
}

브라우저에서 http://localhost:8080/hello 접속

4. 로그 레벨 설정

HelloController 클래스 Logger 추가

@RestController
public class HelloController {
    private static final Logger logger = LoggerFactory.getLogger(HelloController.class);
    @RequestMapping("/hello")
    public String index() {
        logger.debug("debug Hello");
        logger.info("info Hello");
        logger.warn("warn Hello");
        logger.error("error Hello");
        return "hello world!";
    }
}

application.properties 로그 레벨 설정 추가

logging.level.root=INFO
logging.level.com.samsungsds.backend.stock=DEBUG

5. Banner 설정

방법1. StockApplication.java의 main() 수정

@SpringBootApplication
public class StockApplication {

    public static void main(String[] args) {
        
        new SpringApplicationBuilder(StockApplication.class)
            .banner(new Banner() {
                @Override
                public void printBanner(Environment environment, Class<?> sourceClass, PrintStream out) {
                    out.print("Stock Service");
                }
            })
            .build()
            .run(args);
    }
}

방법2. banner.txt 파일 생성 (classpath root)

@SpringBootApplication
public class StockApplication {

    public static void main(String[] args) {
        
        SpringApplication.run(StockApplication.class, args);
    }
}

6. Rest API 구성

domain 패키지 생성, Stock 클래스 및 Result 클래스 생성

public class Stock {

    private String productId;

    private int amount;

    // constructor, getter, setter 생략 ** 구현해 주세요 **
}

public class Result<T> {

    private int errorCode= 200;

    private String errorMessage = "success";

    private T result;

    // constructor, getter, setter 생략 ** 구현해 주세요 **
}

controller 패키지에 StockController 클래스 생성

@RestController
public class StockController {

}

어노테이션으로 RestController임을 명시

@RestController
@RequestMapping("/api/v1/stocks")
public class StockController {

}

context root path를 @RequestMapping 어노테이션으로 명시

@CrossOrigin
@RestController
@RequestMapping("/api/v1/stocks")
public class StockController {

}

CORS를 위해 @CrossOrigin 어노테이션으로 명시

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

@CrossOrigin
@RestController
@RequestMapping("/api/v1/stocks")
public class StockController {

    private static Logger log = LoggerFactory.getLogger(StockController.class);

}

서비스 로깅을 위해 아래와 같이 Logger를 선언

재고 조회를 위한 Rest API 추가

@GetMapping(value = "/{productId}")
public Result<Stock> find(@PathVariable String productId) {
    log.info("find : {}", productId);
    return new Result<Stock> ();
}

브라우저에서 정상 동작 여부 확인
- http://localhost:8080/api/v1/stocks/1

재고 등록, 수정, 삭제를 위한 Rest API 추가

@PostMapping
public Result<String> register(@RequestBody Stock newStock) {
    log.info("register : {}", newStock);
    return new Result<String> ();
}

@PutMapping
public Result<String> modify(@RequestBody Stock newStock) {
    log.info("modify : {}", newStock);
    return new Result<String> ();
}

@DeleteMapping(value = "/{productId}")
public Result remove(@PathVariable String productId) {
    log.info("remove : {}", productId);
    return new Result();
}

7. API Document 생성

Swagger 사용을 위한 Maven Dependency 추가

<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger2</artifactId>
    <version>2.8.0</version>
</dependency>
<dependency>
    <groupId>io.springfox</groupId>
    <artifactId>springfox-swagger-ui</artifactId>
    <version>2.8.0</version>
</dependency>

config 패키지 생성, SwaggerConfig 클래스 생성

@Configuration
@EnableSwagger2
public class SwaggerConfig {

    @Bean
    public Docket api() {
        return new Docket(DocumentationType.SWAGGER_2)
                .select()
                .apis(RequestHandlerSelectors.any())
                .paths(PathSelectors.ant("/api/v1/**"))
                .build();

    }
}

http://localhost:8080/swagger-ui.html 접속하여 swagger 확인
재고 조회/등록/수정/삭제 API 확인 및 테스트
- API 선택 후 Try it out 버튼 클릭
- data 입력 후 excute 버튼 클릭
- response 에서 결과 확인

8. 개발 환경 설정

src/main/resources에 application.yml 파일 생성

프로파일 별 환경 설정
local : 9012 포트, dev : 8080 포트

spring:
  application:
    name: stocks-service

logging:
  level:
    root: INFO
    com.samsungsds.backend.stock: DEBUG

---

spring:
  profiles: local

server:
  port: 9012

---

spring:
  profiles: dev

server:
  port: 8080

IDE에서 spring.profiles.active 값을 local로 설정
http://localhost:9012/swagger-ui.html 에 접속하여 정상 동작을 확인한다.

9. 서비스 개발

JPA, H2 DB 사용을 위해 Maven Dependency 추가

<dependency>
    <groupId>org.springframework.boot</groupId>
    <artifactId>spring-boot-starter-data-jpa</artifactId>
</dependency>
<dependency>
    <groupId>com.h2database</groupId>
    <artifactId>h2</artifactId>
</dependency>

application.yml 파일에 H2 환경 설정 추가

spring:
  application:
    name: sotcks-service
  datasource:
    driver-class-name: org.h2.Driver
    url: jdbc:h2:file:~/h2/DT;AUTO_SERVER=TRUE
    username: dtuser
    password:
  h2:
    console:
      enabled: true         # 관리콘솔 사용
      path: /h2console          # http://localhost:9012/h2console 로 접속하여 관리 콘솔 사용 가능 (default: /h2-console)
  jpa:
    database: H2
    generate-ddl: true          # schema.sql 파일을 사용하여 Table을 생성하도록 설정
    hibernate:
      ddl-auto: update

초기 Schema 생성을 위해 src/main/resources에 schema.sql 파일 생성

CREATE TABLE IF NOT EXISTS `stock` (
    `product_id` varchar(36) NOT NULL,
    `amount` int NOT NULL,
    PRIMARY KEY (`product_id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

도메인 클래스 수정

@Entity : JPA entity로 지정
@Table : JPA entity와 STOCK 테이블과 매핑
@Id : JPA에서 해당 Object의 ID로 인식

import javax.persistence.Entity;
import javax.persistence.Table;
import javax.persistence.Id;

@Entity
@Table(name = "STOCK")
public class Stock implements Serializable {

    @Id
    private String productId;

    private int amount;


    // Constructor, Getter, Setter 생략 ** 구현해 주세요 **
}

repository 패키지 생성 및 StockRepository 인터페이스 생성

@Repository
public interface StockRepository extends CrudRepository<Stock, String> {

    Stock findByAmount(int amount);
}

JPA Query Method 방식

@Repository
public interface StockRepository extends CrudRepository<Stock, String> {


    @Query(value="SELECT * FROM stock WHERE product_id=?1", nativeQuery=true)
    Stock getStockUsingSql(String productId);
    
    @Query(value="SELECT * FROM stock WHERE product_id=:productId", nativeQuery=true)
    Stock getStockUsingSqlWithNamedParam(@Param("productId") String productId);

    @Query(value="SELECT s FROM Stock s WHERE productId=?1", nativeQuery=false)
    Stock getStockUsingJpql(String productId);
}

JPA Native Query 방식

Repository 테스트

src/test/java에 repository 패키지 생성 및 StockRepositoryTest 클래스 생성

@RunWith(SpringRunner.class)
@SpringBootTest
public class StockRepositoryTest {

    @Resource
    StockRepository stockRepository;
    
    @Test
    public void save() {
        
        Stock newStock = new Stock();
        newStock.setProductId("1");
        newStock.setAmount(10);
        
        Stock stock = stockRepository.save(newStock );
        
        assertEquals(10, stock.getAmount());
    }

    @Test
    public void findById() {
        Stock stock = stockRepository.findById("1").orElse(null);
        
        assertEquals(10, stock.getAmount());
    }
    
    @Test
    public void findByAmount() {
        Stock stock = stockRepository.findByAmount(10);
        
        assertEquals("1", stock.getProductId());
    }
    
    @Test
    public void getStockUsingSql() {
        Stock stock = stockRepository.getStockUsingSql("1");
        
        assertEquals(10, stock.getAmount());
    }

    @Test
    public void getStockUsingSqlWithNamedParam() {
        Stock stock = stockRepository.getStockUsingSqlWithNamedParam("1");
        
        assertEquals(10, stock.getAmount());
    }
    
    @Test
    public void getStockUsingJpql() {
        Stock stock = stockRepository.getStockUsingJpql("1");
        
        assertEquals(10, stock.getAmount());
    }

}

service 패키지 생성 및 StockService 인터페이스 생성

public interface StockService {

    Stock find(String productId);

    Stock register(Stock stock);

    Stock modify(Stock stock);

    void remove(String productId);
}

service.impl 패키지 생성 및 StockServiceImpl 클래스 생성

@Service
public class StockServiceImpl implements StockService {

    @Autowired
    private StockRepository stockRepository;

    @Override
    public Stock find(String productId) {
        return stockRepository.findById(productId).orElse(null);
    }

    @Override
    public Stock register(Stock stock) {

        if( find(stock.getProductId()) != null ) {
            return null;
        }

        return stockRepository.save(stock);
    }

    @Override
    public Stock modify(Stock stock) {
        Stock result = find(stock.getProductId());

        if (result == null) {
            return null;
        }

        return  stockRepository.save(stock);
    }

    @Override
    public void remove(String productId) {
        stockRepository.deleteById(productId);
    }
}

StockController 클래스에서 StockService를 사용하여 기능 구현

@CrossOrigin
@RestController
@RequestMapping("/api/v1/stocks")
public class StockController {

    private static Logger log = LoggerFactory.getLogger(StockController.class);
    private StockService stockService;

    @Autowired
    public StockController(StockService stockService) {
        this.stockService = stockService;
    }

    @GetMapping(value = "/{productId}")
    public Result<Stock> find(@PathVariable String productId) {
        log.info("find : " + productId);
        Result<Stock> result = new Result<>();

        Stock stock = stockService.find(productId);
        if (stock == null) {
            result.setErrorCode(HttpStatus.NOT_FOUND.value());
            result.setErrorMessage("Not found.");
        } else {
            result.setResult(stock);
        }

        return result;
    }

    @PostMapping
    public Result<String> register(@RequestBody Stock newStock) {
        log.info("register : " + newStock);
        Result<String> result = new Result<>();

        Stock resultStock = stockService.register(newStock);
        if (resultStock == null) {
            result.setErrorCode(HttpStatus.BAD_REQUEST.value());
            result.setErrorMessage("Already Exists.");
        } else {
            result.setResult(resultStock.getProductId());
        }

        return result;
    }

    @DeleteMapping(value = "/{productId}")
    public Result remove(@PathVariable String productId) {
        log.info("remove : " + productId);
        stockService.remove(productId);
        return new Result();
    }

    @PutMapping
    public Result<String> modify(@RequestBody Stock newStock) {
        log.info("modify : " + newStock);
        Result<String> result = new Result<>();

        Stock resultStock = stockService.modify(newStock);
        if (resultStock == null) {
            result.setErrorCode(HttpStatus.NOT_FOUND.value());
            result.setErrorMessage("Not found.");
        } else {
            result.setResult(resultStock.getProductId());
        }

        return result;
    }
}

Swagger를 활용하여 재고 조회/등록/수정/삭제 기능 테스트

10. Service Unit Test 작성

src/test/java에 service.impl 패키지 생성 및 StockServiceImplTest 클래스 생성

@RunWith(SpringRunner.class)
@SpringBootTest
public class StockServiceImplTest {

    @Resource
    StockService stockService;
        
    @Test
    public void find() {
        Stock stock = stockService.find("1");
        
        assertEquals("1", stock.getProductId());
        assertEquals(1000, stock.getAmount());
    }
}

Mock-up 테스트로 변경

@RunWith(SpringRunner.class)
@SpringBootTest
public class StockServiceImplTest {

    @Resource
    StockService stockService;
    
    @MockBean
    StockRepository stockRepository;
    
    @Test
    public void find() {
        Stock returnStock = new Stock();
        returnStock.setProductId("1");
        returnStock.setAmount(1000);;
        when(stockRepository.findById("1")).thenReturn(Optional.of(returnStock));
        
        Stock stock = stockService.find("1");
        
        assertEquals("1", stock.getProductId());
        assertEquals(1000, stock.getAmount());
        verify(stockRepository, times(1)).findById("1");
    }
}

11. Controller Unit Test 작성

src/test/java에 controller 패키지 생성 및 StockControllerTest 클래스 생성

package com.samsungsds.backend.stock.controllers;

import org.springframework.context.ApplicationContext;

@RunWith(SpringRunner.class)
public class StockControllerTest {

    @Autowired
    private ApplicationContext applicationContext;

}

서비스 mocking 및 Object 생성

@RunWith(SpringRunner.class)
public class StockControllerTest {

    @Autowired
    private ApplicationContext applicationContext;

    private StockController stockController;
    private StockService mockStockService;

    @Before
    public void setUp() throws Exception {

        mockStockService = mock(StockService.class);
        stockController = new StockController(mockStockService);
    }
}

테스트 생성

@RunWith(SpringRunner.class)
public class StockControllerTest {

    @Autowired
    private ApplicationContext applicationContext;

    private StockController stockController;
    private StockService mockStockService;

    @Before
    public void setUp() throws Exception {

        mockStockService = mock(StockService.class);
        stockController = new StockController(mockStockService);
    }

    @Test
    public void givenProductId_whenFind_thenReturnStock() {
    
        //given
        String productId = "productId";
        Stock stock = new Stock(productId, 0);
        when(mockStockService.find(productId)).thenReturn(stock);
    
        //when
        Result<Stock> result = stockController.find(productId);
    
        //then
        verify(mockStockService, times(1)).find(productId);
        assertThat(result.getErrorCode()).isEqualTo(HttpStatus.OK.value());
        assertThat(result.getResult()).isEqualTo(stock);
    }
    
    @Test
    public void givenNonExistedProductId_whenFind_thenReturnError() {
    
        //given
        String productId = "productId";
        when(mockStockService.find(productId)).thenReturn(null);
    
        //when
        Result<Stock> result = stockController.find(productId);
    
        //then
        verify(mockStockService, times(1)).find(productId);
        assertThat(result.getErrorCode()).isEqualTo(HttpStatus.NOT_FOUND.value());
        assertThat(result.getErrorMessage()).isEqualTo("Not found.");
    }
}

12. MockMvc를 활용한 Controller Unit Test 작성

src/test/java의 controller 패키지에 StockControllerMvcMockTest 클래스 생성

package com.samsungsds.backend.stock.controllers;

@RunWith(SpringRunner.class)
@WebMvcTest(StockController.class)
public class StockControllerMockMvcTest {

    @Autowired
    MockMvc mockMvc;
}

테스트 작성

@Test
public void find() throws Exception {

    mockMvc.perform(get("/api/v1/stocks/1"))
            .andExpect(status().isOk())
            .andExpect(content().json("{\"errorCode\":200,\"errorMessage\":\"success\",\"result\":{\"productId\":\"1\",\"amount\":10}}"))
            .andExpect(jsonPath("$.result.productId").value("1"))
            .andExpect(jsonPath("$.result.amount").value("10"))
            ;  
}

@MockBean을 사용하여 StockService를 mocking한 후 stub 작성

@Autowired
MockMvc mockMvc;

@MockBean
StockService stockService;


@Test
public void find() throws Exception {

    Stock stock = new Stock("1", 10);
    when(stockService.find("1")).thenReturn(stock);
    
    mockMvc.perform(get("/api/v1/stocks/1"))
            .andExpect(status().isOk())
            .andExpect(content().json("{\"errorCode\":200,\"errorMessage\":\"success\",\"result\":{\"productId\":\"1\",\"amount\":10}}"))
            .andExpect(jsonPath("$.result.productId").value("1"))
            .andExpect(jsonPath("$.result.amount").value("10"))
            ;  
    verify(stockService, times(1)).find("1");
}

13. Component Test 작성

src/test에 resources 폴더를 생성하고 테스트 환경을 위한 application.yml 생성

spring:
  profiles:
    active: test                        # test 환경으로 프로파일 적용
  application:
    name: stocks-service
  datasource:
    driver-class-name: org.h2.Driver
    url: jdbc:h2:mem:testdb             # In memory DB 설정
    username: dtuser
    password:
  jpa:
    database: H2
    generate-ddl: true
    hibernate:
        ddl-auto: update

src/test/java의 controller 패키지에 StockControllerFuncTest 클래스 생성

@RunWith(SpringJUnit4ClassRunner.class)
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class StockControllerFuncTest {

}

@RunWIth, @SpringBootTest 어노테이션으로 스프링 컨텍스트와 서블릿 컨테이너를 띄워 실제 서버에 테스트 하는 환경을 구성

@RunWith(SpringJUnit4ClassRunner.class)
@AutoConfigureMockMvc
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class StockControllerFuncTest {

    @Autowired
    MockMvc mockMvc;
}

MockMvc 객체는 브라우저에서의 Request와 Response를 mocking한 것

Component Test 완성

@RunWith(SpringJUnit4ClassRunner.class)
@AutoConfigureMockMvc
@SpringBootTest(webEnvironment = SpringBootTest.WebEnvironment.RANDOM_PORT)
public class StockControllerFuncTest {

    @Autowired
    MockMvc mockMvc;

    @Autowired
    StockRepository stockRepository;

    @Test
    public void givenProductId_whenFind_thenReturnStock() throws Exception {

        // data clear
        stockRepository.deleteAll();

        // insert init data
        Stock stock = new Stock("productId", 10);
        stockRepository.save(stock);

        mockMvc.perform(get("/api/v1/stocks/productId"))
                .andExpect(status().isOk())
                .andExpect(content().json("{\"errorCode\":200,\"errorMessage\":\"success\",\"result\":{\"productId\":\"productId\",\"amount\":10}}"))
                .andExpect(jsonPath("$.result.productId").value("productId"))
                .andExpect(jsonPath("$.result.amount").value("10"))
                ;  
    }

    @Test
    public void givenNonExistedProductId_whenFind_thenReturnError() throws Exception {

        // data clear
        stockRepository.deleteAll();

        mockMvc.perform(get("/api/v1/stocks/productId"))
                .andExpect(status().isOk())
                .andExpect(content().json("{\"errorCode\":404,\"errorMessage\":\"Not found.\",\"result\":null}"))
                .andExpect(jsonPath("$.errorCode").value(404))
                .andExpect(jsonPath("$.result").doesNotExist())
                ;
    }
}

StockRepository를 Autowired하여 원하는 데이터로 초기화
MockMvc.perform 메서드를 통해 원하는 Request를 테스트 서버에 보낼 수 있고 결과를 비교하여 테스트

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