pom.xml

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<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 https://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <parent>
+        <groupId>org.springframework.boot</groupId>
+        <artifactId>spring-boot-starter-parent</artifactId>
+        <version>3.2.5</version>
+        <relativePath/>
+    </parent>
+
+    <groupId>com.acquirex</groupId>
+    <artifactId>proj-acquirex</artifactId>
+    <version>1.0.0-SNAPSHOT</version>
+    <name>proj-acquirex</name>
+    <description>카드 매입 승인 시스템 - Spring Boot 3</description>
+
+    <properties>
+        <java.version>17</java.version>
+    </properties>
+
+    <dependencies>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-web</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-data-jpa</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-validation</artifactId>
+        </dependency>
+        <dependency>
+            <groupId>com.h2database</groupId>
+            <artifactId>h2</artifactId>
+            <scope>runtime</scope>
+        </dependency>
+        <dependency>
+            <groupId>org.springframework.boot</groupId>
+            <artifactId>spring-boot-starter-test</artifactId>
+            <scope>test</scope>
+        </dependency>
+    </dependencies>
+
+    <build>
+        <plugins>
+            <plugin>
+                <groupId>org.springframework.boot</groupId>
+                <artifactId>spring-boot-maven-plugin</artifactId>
+            </plugin>
+        </plugins>
+    </build>
+</project>

src/main/java/com/acquirex/AcquirexApplication.java

@@ -0,0 +1,12 @@
+package com.acquirex;
+
+import org.springframework.boot.SpringApplication;
+import org.springframework.boot.autoconfigure.SpringBootApplication;
+
+@SpringBootApplication
+public class AcquirexApplication {
+
+    public static void main(String[] args) {
+        SpringApplication.run(AcquirexApplication.class, args);
+    }
+}

src/main/java/com/acquirex/controller/CardAcquisitionController.java

@@ -0,0 +1,44 @@
+package com.acquirex.controller;
+
+import com.acquirex.dto.AcquisitionDto.Request;
+import com.acquirex.dto.AcquisitionDto.Response;
+import com.acquirex.entity.CardAcquisition;
+import com.acquirex.service.CardAcquisitionService;
+import jakarta.validation.Valid;
+import org.springframework.http.HttpStatus;
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.*;
+
+/**
+ * 카드 매입 승인 REST API 컨트롤러
+ * Spring Boot 3: @RestController, @RequestMapping 유지
+ */
+@RestController
+@RequestMapping("/api/v1/acquisitions")
+public class CardAcquisitionController {
+
+    private final CardAcquisitionService acquisitionService;
+
+    public CardAcquisitionController(CardAcquisitionService acquisitionService) {
+        this.acquisitionService = acquisitionService;
+    }
+
+    @PostMapping
+    public ResponseEntity<Response> requestAcquisition(@Valid @RequestBody Request request) {
+        Response response = acquisitionService.processAcquisition(request);
+        if ("APPROVED".equals(response.getStatus())) {
+            return ResponseEntity.status(HttpStatus.CREATED).body(response);
+        }
+        return ResponseEntity.status(HttpStatus.BAD_REQUEST).body(response);
+    }
+
+    @GetMapping("/{id}")
+    public ResponseEntity<CardAcquisition> getAcquisition(@PathVariable Long id) {
+        return ResponseEntity.ok(acquisitionService.findById(id));
+    }
+
+    @GetMapping("/approval/{approvalCode}")
+    public ResponseEntity<CardAcquisition> getByApprovalCode(@PathVariable String approvalCode) {
+        return ResponseEntity.ok(acquisitionService.findByApprovalCode(approvalCode));
+    }
+}

src/main/java/com/acquirex/dto/AcquisitionDto.java

@@ -0,0 +1,88 @@
+package com.acquirex.dto;
+
+import jakarta.validation.constraints.*;
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+
+/**
+ * 카드 매입 요청/응답 DTO
+ * Spring Boot 3: javax.validation → jakarta.validation
+ */
+public class AcquisitionDto {
+
+    // ========== Request DTO ==========
+    public static class Request {
+        @NotBlank(message = "카드번호는 필수입니다")
+        @Size(min = 13, max = 19, message = "카드번호 길이가 올바르지 않습니다")
+        private String cardNumber;
+
+        @NotBlank(message = "가맹점ID는 필수입니다")
+        private String merchantId;
+
+        @NotNull(message = "금액은 필수입니다")
+        @DecimalMin(value = "0.01", message = "금액은 0보다 커야 합니다")
+        @Digits(integer = 13, fraction = 2, message = "금액 형식이 올바르지 않습니다")
+        private BigDecimal amount;
+
+        @NotBlank(message = "통화는 필수입니다")
+        @Size(min = 3, max = 3, message = "통화 코드는 3자리입니다")
+        private String currency;
+
+        public String getCardNumber() { return cardNumber; }
+        public void setCardNumber(String cardNumber) { this.cardNumber = cardNumber; }
+        public String getMerchantId() { return merchantId; }
+        public void setMerchantId(String merchantId) { this.merchantId = merchantId; }
+        public BigDecimal getAmount() { return amount; }
+        public void setAmount(BigDecimal amount) { this.amount = amount; }
+        public String getCurrency() { return currency; }
+        public void setCurrency(String currency) { this.currency = currency; }
+    }
+
+    // ========== Response DTO ==========
+    public static class Response {
+        private Long id;
+        private String approvalCode;
+        private String status;
+        private String message;
+        private BigDecimal amount;
+        private String currency;
+        private LocalDateTime approvalTime;
+
+        public Response() {}
+
+        public static Response success(Long id, String approvalCode, BigDecimal amount, String currency) {
+            Response response = new Response();
+            response.setId(id);
+            response.setApprovalCode(approvalCode);
+            response.setStatus("APPROVED");
+            response.setMessage("매입 승인이 완료되었습니다");
+            response.setAmount(amount);
+            response.setCurrency(currency);
+            response.setApprovalTime(LocalDateTime.now());
+            return response;
+        }
+
+        public static Response rejected(Long id, String reason) {
+            Response response = new Response();
+            response.setId(id);
+            response.setStatus("REJECTED");
+            response.setMessage(reason);
+            return response;
+        }
+
+        public Long getId() { return id; }
+        public void setId(Long id) { this.id = id; }
+        public String getApprovalCode() { return approvalCode; }
+        public void setApprovalCode(String approvalCode) { this.approvalCode = approvalCode; }
+        public String getStatus() { return status; }
+        public void setStatus(String status) { this.status = status; }
+        public String getMessage() { return message; }
+        public void setMessage(String message) { this.message = message; }
+        public BigDecimal getAmount() { return amount; }
+        public void setAmount(BigDecimal amount) { this.amount = amount; }
+        public String getCurrency() { return currency; }
+        public void setCurrency(String currency) { this.currency = currency; }
+        public LocalDateTime getApprovalTime() { return approvalTime; }
+        public void setApprovalTime(LocalDateTime approvalTime) { this.approvalTime = approvalTime; }
+    }
+}

src/main/java/com/acquirex/entity/CardAcquisition.java

@@ -0,0 +1,89 @@
+package com.acquirex.entity;
+
+import jakarta.persistence.*;
+import org.springframework.data.jpa.repository.JpaRepository;
+import org.springframework.stereotype.Repository;
+
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+import java.util.List;
+import java.util.Optional;
+
+/**
+ * 카드 매입 승인 엔티티 및 리포지토리
+ * Spring Boot 3: javax.persistence → jakarta.persistence
+ */
+@Entity
+@Table(name = "card_acquisitions")
+public class CardAcquisition {
+
+    @Id
+    @GeneratedValue(strategy = GenerationType.IDENTITY)
+    private Long id;
+
+    @Column(name = "card_number", nullable = false, length = 16)
+    private String cardNumber;
+
+    @Column(name = "merchant_id", nullable = false)
+    private String merchantId;
+
+    @Column(name = "amount", nullable = false, precision = 15, scale = 2)
+    private BigDecimal amount;
+
+    @Column(name = "currency", nullable = false, length = 3)
+    private String currency;
+
+    @Enumerated(EnumType.STRING)
+    @Column(name = "status", nullable = false, length = 20)
+    private AcquisitionStatus status;
+
+    @Column(name = "approval_code", length = 12)
+    private String approvalCode;
+
+    @Column(name = "request_time", nullable = false)
+    private LocalDateTime requestTime;
+
+    @Column(name = "approval_time")
+    private LocalDateTime approvalTime;
+
+    @Column(name = "reject_reason", length = 255)
+    private String rejectReason;
+
+    public enum AcquisitionStatus {
+        PENDING, APPROVED, REJECTED, CANCELLED
+    }
+
+    public CardAcquisition() {
+        this.requestTime = LocalDateTime.now();
+        this.status = AcquisitionStatus.PENDING;
+    }
+
+    // Getters and Setters
+    public Long getId() { return id; }
+    public void setId(Long id) { this.id = id; }
+    public String getCardNumber() { return cardNumber; }
+    public void setCardNumber(String cardNumber) { this.cardNumber = cardNumber; }
+    public String getMerchantId() { return merchantId; }
+    public void setMerchantId(String merchantId) { this.merchantId = merchantId; }
+    public BigDecimal getAmount() { return amount; }
+    public void setAmount(BigDecimal amount) { this.amount = amount; }
+    public String getCurrency() { return currency; }
+    public void setCurrency(String currency) { this.currency = currency; }
+    public AcquisitionStatus getStatus() { return status; }
+    public void setStatus(AcquisitionStatus status) { this.status = status; }
+    public String getApprovalCode() { return approvalCode; }
+    public void setApprovalCode(String approvalCode) { this.approvalCode = approvalCode; }
+    public LocalDateTime getRequestTime() { return requestTime; }
+    public void setRequestTime(LocalDateTime requestTime) { this.requestTime = requestTime; }
+    public LocalDateTime getApprovalTime() { return approvalTime; }
+    public void setApprovalTime(LocalDateTime approvalTime) { this.approvalTime = approvalTime; }
+    public String getRejectReason() { return rejectReason; }
+    public void setRejectReason(String rejectReason) { this.rejectReason = rejectReason; }
+
+    @Repository
+    public interface CardAcquisitionRepository extends JpaRepository<CardAcquisition, Long> {
+        List<CardAcquisition> findByStatus(AcquisitionStatus status);
+        Optional<CardAcquisition> findByApprovalCode(String approvalCode);
+        List<CardAcquisition> findByMerchantId(String merchantId);
+    }
+}

src/main/java/com/acquirex/service/CardAcquisitionService.java

@@ -0,0 +1,116 @@
+package com.acquirex.service;
+
+import com.acquirex.dto.AcquisitionDto.Request;
+import com.acquirex.dto.AcquisitionDto.Response;
+import com.acquirex.entity.CardAcquisition;
+import com.acquirex.entity.CardAcquisition.AcquisitionStatus;
+import com.acquirex.entity.CardAcquisition.CardAcquisitionRepository;
+import org.springframework.stereotype.Service;
+import org.springframework.transaction.annotation.Transactional;
+
+import java.math.BigDecimal;
+import java.time.LocalDateTime;
+import java.util.Random;
+
+@Service
+public class CardAcquisitionService {
+
+    private static final BigDecimal MAX_APPROVAL_AMOUNT = new BigDecimal("10000000");
+    private static final BigDecimal SUSPICIOUS_AMOUNT_THRESHOLD = new BigDecimal("5000000");
+
+    private final CardAcquisitionRepository repository;
+    private final Random approvalCodeGenerator = new Random();
+
+    public CardAcquisitionService(CardAcquisitionRepository repository) {
+        this.repository = repository;
+    }
+
+    @Transactional
+    public Response processAcquisition(Request request) {
+        CardAcquisition acquisition = createAcquisition(request);
+        CardAcquisition saved = repository.save(acquisition);
+
+        if (!validateCardNumber(request.getCardNumber())) {
+            return rejectAcquisition(saved, "유효하지 않은 카드번호입니다");
+        }
+
+        if (request.getAmount().compareTo(MAX_APPROVAL_AMOUNT) > 0) {
+            return rejectAcquisition(saved, "승인 한도를 초과했습니다");
+        }
+
+        if (isSuspiciousTransaction(request)) {
+            return rejectAcquisition(saved, "의심스러운 거래로 거부되었습니다");
+        }
+
+        return approveAcquisition(saved);
+    }
+
+    private CardAcquisition createAcquisition(Request request) {
+        CardAcquisition acquisition = new CardAcquisition();
+        acquisition.setCardNumber(maskCardNumber(request.getCardNumber()));
+        acquisition.setMerchantId(request.getMerchantId());
+        acquisition.setAmount(request.getAmount());
+        acquisition.setCurrency(request.getCurrency());
+        acquisition.setStatus(AcquisitionStatus.PENDING);
+        return acquisition;
+    }
+
+    private boolean validateCardNumber(String cardNumber) {
+        if (cardNumber == null || cardNumber.length() < 13) return false;
+        int sum = 0;
+        boolean alternate = false;
+        for (int i = cardNumber.length() - 1; i >= 0; i--) {
+            int digit = Character.getNumericValue(cardNumber.charAt(i));
+            if (alternate) {
+                digit *= 2;
+                if (digit > 9) digit -= 9;
+            }
+            sum += digit;
+            alternate = !alternate;
+        }
+        return sum % 10 == 0;
+    }
+
+    private boolean isSuspiciousTransaction(Request request) {
+        return request.getAmount().compareTo(SUSPICIOUS_AMOUNT_THRESHOLD) >= 0
+                && request.getCardNumber().startsWith("9999");
+    }
+
+    private String generateApprovalCode() {
+        return String.format("%06d", approvalCodeGenerator.nextInt(999999));
+    }
+
+    private String maskCardNumber(String cardNumber) {
+        if (cardNumber == null || cardNumber.length() < 8) return cardNumber;
+        return cardNumber.substring(0, 4) + "****" + cardNumber.substring(cardNumber.length() - 4);
+    }
+
+    private Response approveAcquisition(CardAcquisition acquisition) {
+        String approvalCode = generateApprovalCode();
+        acquisition.setStatus(AcquisitionStatus.APPROVED);
+        acquisition.setApprovalCode(approvalCode);
+        acquisition.setApprovalTime(LocalDateTime.now());
+        repository.save(acquisition);
+        return Response.success(acquisition.getId(), approvalCode, acquisition.getAmount(), acquisition.getCurrency());
+    }
+
+    private Response rejectAcquisition(CardAcquisition acquisition, String reason) {
+        acquisition.setStatus(AcquisitionStatus.REJECTED);
+        acquisition.setRejectReason(reason);
+        acquisition.setApprovalTime(LocalDateTime.now());
+        repository.save(acquisition);
+        return Response.rejected(acquisition.getId(), reason);
+    }
+
+    @Transactional(readOnly = true)
+    public CardAcquisition findById(Long id) {
+        return repository.findById(id)
+                .orElseThrow(() -> new IllegalArgumentException("매입 정보를 찾을 수 없습니다: " + id));
+    }
+
+    @Transactional(readOnly = true)
+    public CardAcquisition findByApprovalCode(String approvalCode) {
+        return repository.findByApprovalCode(approvalCode)
+                .orElseThrow(() -> new IllegalArgumentException("승인코드를 찾을 수 없습니다: " + approvalCode));
+    }
+}

src/main/resources/application.yml

@@ -0,0 +1,31 @@
+spring:
+  application:
+    name: proj-acquirex
+
+  datasource:
+    url: jdbc:h2:mem:acquirexdb;DB_CLOSE_DELAY=-1;DB_CLOSE_ON_EXIT=FALSE
+    driver-class-name: org.h2.Driver
+    username: sa
+    password:
+
+  jpa:
+    hibernate:
+      ddl-auto: create-drop
+    show-sql: true
+    properties:
+      hibernate:
+        format_sql: true
+        dialect: org.hibernate.dialect.H2Dialect
+
+  h2:
+    console:
+      enabled: true
+      path: /h2-console
+
+server:
+  port: 8080
+
+logging:
+  level:
+    com.acquirex: DEBUG
+    org.hibernate.SQL: DEBUG

src/test/java/com/acquirex/service/CardAcquisitionServiceTest.java

@@ -0,0 +1,145 @@
+package com.acquirex.service;
+
+import com.acquirex.dto.AcquisitionDto.Request;
+import com.acquirex.dto.AcquisitionDto.Response;
+import com.acquirex.entity.CardAcquisition;
+import com.acquirex.entity.CardAcquisition.CardAcquisitionRepository;
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.DisplayName;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.extension.ExtendWith;
+import org.mockito.Mock;
+import org.mockito.junit.jupiter.MockitoExtension;
+
+import java.math.BigDecimal;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.Mockito.*;
+
+@ExtendWith(MockitoExtension.class)
+class CardAcquisitionServiceTest {
+
+    @Mock
+    private CardAcquisitionRepository repository;
+
+    private CardAcquisitionService service;
+
+    @BeforeEach
+    void setUp() {
+        service = new CardAcquisitionService(repository);
+    }
+
+    @Test
+    @DisplayName("유효한 카드로 정상 승인 처리")
+    void processAcquisition_ValidCard_ShouldApprove() {
+        Request request = new Request();
+        request.setCardNumber("4532015112830366");
+        request.setMerchantId("MERCHANT001");
+        request.setAmount(new BigDecimal("100000"));
+        request.setCurrency("KRW");
+
+        when(repository.save(any(CardAcquisition.class)))
+                .thenAnswer(invocation -> {
+                    CardAcquisition acq = invocation.getArgument(0);
+                    acq.setId(1L);
+                    return acq;
+                });
+
+        Response response = service.processAcquisition(request);
+
+        assertEquals("APPROVED", response.getStatus());
+        assertNotNull(response.getApprovalCode());
+        assertEquals(6, response.getApprovalCode().length());
+        assertEquals(new BigDecimal("100000"), response.getAmount());
+        assertEquals("KRW", response.getCurrency());
+    }
+
+    @Test
+    @DisplayName("유효하지 않은 카드번호 거부")
+    void processAcquisition_InvalidCardNumber_ShouldReject() {
+        Request request = new Request();
+        request.setCardNumber("1234567890123456");
+        request.setMerchantId("MERCHANT001");
+        request.setAmount(new BigDecimal("50000"));
+        request.setCurrency("KRW");
+
+        when(repository.save(any(CardAcquisition.class)))
+                .thenAnswer(invocation -> {
+                    CardAcquisition acq = invocation.getArgument(0);
+                    acq.setId(1L);
+                    return acq;
+                });
+
+        Response response = service.processAcquisition(request);
+
+        assertEquals("REJECTED", response.getStatus());
+        assertNull(response.getApprovalCode());
+        assertTrue(response.getMessage().contains("유효하지 않은"));
+    }
+
+    @Test
+    @DisplayName("한도 초과 거래 거부")
+    void processAcquisition_ExceedLimit_ShouldReject() {
+        Request request = new Request();
+        request.setCardNumber("4532015112830366");
+        request.setMerchantId("MERCHANT001");
+        request.setAmount(new BigDecimal("15000000"));
+        request.setCurrency("KRW");
+
+        when(repository.save(any(CardAcquisition.class)))
+                .thenAnswer(invocation -> {
+                    CardAcquisition acq = invocation.getArgument(0);
+                    acq.setId(1L);
+                    return acq;
+                });
+
+        Response response = service.processAcquisition(request);
+
+        assertEquals("REJECTED", response.getStatus());
+        assertTrue(response.getMessage().contains("한도"));
+    }
+
+    @Test
+    @DisplayName("의심스러운 거래 거부 (9999 시작 + 고액)")
+    void processAcquisition_SuspiciousTransaction_ShouldReject() {
+        Request request = new Request();
+        request.setCardNumber("9999123456789012");
+        request.setMerchantId("MERCHANT001");
+        request.setAmount(new BigDecimal("6000000"));
+        request.setCurrency("KRW");
+
+        when(repository.save(any(CardAcquisition.class)))
+                .thenAnswer(invocation -> {
+                    CardAcquisition acq = invocation.getArgument(0);
+                    acq.setId(1L);
+                    return acq;
+                });
+
+        Response response = service.processAcquisition(request);
+
+        assertEquals("REJECTED", response.getStatus());
+        assertTrue(response.getMessage().contains("의심스러운"));
+    }
+
+    @Test
+    @DisplayName("카드번호 마스킹 처리 확인")
+    void processAcquisition_CardNumberMasked() {
+        Request request = new Request();
+        request.setCardNumber("4532015112830366");
+        request.setMerchantId("MERCHANT001");
+        request.setAmount(new BigDecimal("100000"));
+        request.setCurrency("KRW");
+
+        when(repository.save(any(CardAcquisition.class)))
+                .thenAnswer(invocation -> {
+                    CardAcquisition acq = invocation.getArgument(0);
+                    acq.setId(1L);
+                    return acq;
+                });
+
+        service.processAcquisition(request);
+
+        verify(repository, times(2)).save(argThat(acq -> acq.getCardNumber().equals("4532****0366")));
+    }
+}