✨Feat: 웹소켓 기반 채팅 기능 구현

build.gradle

@@ -61,6 +61,9 @@ dependencies {
     // Image
     implementation("com.sksamuel.scrimage:scrimage-core:4.3.5")
     implementation("com.sksamuel.scrimage:scrimage-webp:4.3.5")
+
+    // WebSocket + STOMP
+    implementation 'org.springframework.boot:spring-boot-starter-websocket'
 }
 
 tasks.named('test') {

src/main/java/com/sku/refit/domain/chat/controller/ChatController.java

@@ -0,0 +1,57 @@
+/* 
+ * Copyright (c) SKU 다시입을Lab 
+ */
+package com.sku.refit.domain.chat.controller;
+
+/*
+ * Copyright (c) SKU 다시입을Lab
+ */
+
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.GetMapping;
+import org.springframework.web.bind.annotation.PathVariable;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.PutMapping;
+import org.springframework.web.bind.annotation.RequestMapping;
+import org.springframework.web.bind.annotation.RequestParam;
+
+import com.sku.refit.domain.chat.dto.response.ChatMessageResponse;
+import com.sku.refit.domain.chat.dto.response.ChatRoomResponse;
+import com.sku.refit.global.page.response.InfiniteResponse;
+import com.sku.refit.global.response.BaseResponse;
+
+import io.swagger.v3.oas.annotations.Operation;
+import io.swagger.v3.oas.annotations.Parameter;
+import io.swagger.v3.oas.annotations.tags.Tag;
+
+@Tag(name = "채팅", description = "채팅 관련 API")
+@RequestMapping("/api/chats")
+public interface ChatController {
+
+  @PostMapping("/exchange/{postId}")
+  @Operation(summary = "새 채팅방 생성", description = "특정 교환 게시글의 채팅방을 생성합니다.")
+  ResponseEntity<BaseResponse<ChatRoomResponse>> createChatRoom(
+      @Parameter(description = "채팅방을 생성할 교환글 식별자", example = "1") @PathVariable Long postId);
+
+  @GetMapping("/rooms")
+  @Operation(summary = "채팅방 조회", description = "사용자의 채팅방 내역을 조회합니다.")
+  ResponseEntity<BaseResponse<InfiniteResponse<ChatRoomResponse>>> getMyChatRooms(
+      @Parameter(description = "마지막으로 조회한 채팅방 식별자(첫 조회 시 생략)", example = "5")
+          @RequestParam(required = false)
+          Long lastChatRoomId,
+      @Parameter(description = "한 번에 조회할 채팅방 개수", example = "5") @RequestParam(defaultValue = "5")
+          Integer size);
+
+  @GetMapping("/rooms/{roomId}/messages")
+  ResponseEntity<BaseResponse<InfiniteResponse<ChatMessageResponse>>> getMessages(
+      @Parameter(description = "채팅방 식별자", example = "1") @PathVariable Long roomId,
+      @Parameter(description = "마지막으로 조회한 채팅 식별자(첫 조회 시 생략)", example = "10")
+          @RequestParam(required = false)
+          Long lastChatId,
+      @Parameter(description = "한 번에 조회할 채팅 개수", example = "10") @RequestParam(defaultValue = "10")
+          Integer size);
+
+  @PutMapping("/rooms/{roomId}/read")
+  ResponseEntity<BaseResponse<Void>> readMessages(
+      @Parameter(description = "채팅방 식별자", example = "1") @PathVariable Long roomId);
+}

src/main/java/com/sku/refit/domain/chat/controller/ChatControllerImpl.java

@@ -0,0 +1,52 @@
+/* 
+ * Copyright (c) SKU 다시입을Lab 
+ */
+package com.sku.refit.domain.chat.controller;
+
+import org.springframework.http.ResponseEntity;
+import org.springframework.web.bind.annotation.RestController;
+
+import com.sku.refit.domain.chat.dto.response.ChatMessageResponse;
+import com.sku.refit.domain.chat.dto.response.ChatRoomResponse;
+import com.sku.refit.domain.chat.service.ChatService;
+import com.sku.refit.global.page.response.InfiniteResponse;
+import com.sku.refit.global.response.BaseResponse;
+
+import lombok.RequiredArgsConstructor;
+
+@RestController
+@RequiredArgsConstructor
+public class ChatControllerImpl implements ChatController {
+
+  private final ChatService chatService;
+
+  @Override
+  public ResponseEntity<BaseResponse<ChatRoomResponse>> createChatRoom(Long postId) {
+
+    ChatRoomResponse response = chatService.createChatRoom(postId);
+    return ResponseEntity.ok(BaseResponse.success(response));
+  }
+
+  @Override
+  public ResponseEntity<BaseResponse<InfiniteResponse<ChatRoomResponse>>> getMyChatRooms(
+      Long lastChatRoomId, Integer size) {
+
+    return ResponseEntity.ok(
+        BaseResponse.success(chatService.getMyChatRooms(lastChatRoomId, size)));
+  }
+
+  @Override
+  public ResponseEntity<BaseResponse<InfiniteResponse<ChatMessageResponse>>> getMessages(
+      Long roomId, Long lastChatId, Integer size) {
+
+    return ResponseEntity.ok(
+        BaseResponse.success(chatService.getMessages(roomId, lastChatId, size)));
+  }
+
+  @Override
+  public ResponseEntity<BaseResponse<Void>> readMessages(Long roomId) {
+
+    chatService.readMessages(roomId);
+    return ResponseEntity.ok().build();
+  }
+}

src/main/java/com/sku/refit/domain/chat/controller/ChatMessageController.java

@@ -0,0 +1,33 @@
+/* 
+ * Copyright (c) SKU 다시입을Lab 
+ */
+package com.sku.refit.domain.chat.controller;
+
+import java.security.Principal;
+
+import org.springframework.messaging.handler.annotation.MessageMapping;
+import org.springframework.stereotype.Controller;
+
+import com.sku.refit.domain.chat.dto.request.ChatMessageRequest;
+import com.sku.refit.domain.chat.service.ChatService;
+
+import lombok.RequiredArgsConstructor;
+import lombok.extern.slf4j.Slf4j;
+
+@Controller
+@RequiredArgsConstructor
+@Slf4j
+public class ChatMessageController {
+
+  private final ChatService chatService;
+
+  @MessageMapping("/chat/send")
+  public void sendMessage(ChatMessageRequest request, Principal principal) {
+
+    log.info(
+        "[WS CONTROLLER] sendMessage 호출됨 roomId={}, principal={}",
+        request.getRoomId(),
+        principal != null ? principal.getName() : "null");
+    chatService.sendMessage(request, principal);
+  }
+}

src/main/java/com/sku/refit/domain/chat/dto/request/ChatMessageRequest.java

@@ -0,0 +1,17 @@
+/* 
+ * Copyright (c) SKU 다시입을Lab 
+ */
+package com.sku.refit.domain.chat.dto.request;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Getter
+@NoArgsConstructor
+@AllArgsConstructor
+public class ChatMessageRequest {
+
+  private Long roomId;
+  private String content;
+}

src/main/java/com/sku/refit/domain/chat/dto/response/ChatMessageResponse.java

@@ -0,0 +1,31 @@
+/* 
+ * Copyright (c) SKU 다시입을Lab 
+ */
+package com.sku.refit.domain.chat.dto.response;
+
+import java.time.LocalDateTime;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.Builder;
+import lombok.Getter;
+
+@Getter
+@Builder
+@Schema(title = "ChatMessageResponse DTO", description = "채팅 메세지 응답 반환")
+public class ChatMessageResponse {
+
+  @Schema(description = "채팅 메세지 식별자", example = "1")
+  private Long messageId;
+
+  @Schema(description = "채팅방 식별자", example = "1")
+  private Long roomId;
+
+  @Schema(description = "채팅 발신자", example = "김다입")
+  private String senderNickname;
+
+  @Schema(description = "채팅 내용", example = "안녕하세요. 교환 원하시나요?")
+  private String content;
+
+  @Schema(description = "메세지 작성 시간", example = "20250101T120000")
+  private LocalDateTime createdAt;
+}

src/main/java/com/sku/refit/domain/chat/dto/response/ChatRoomResponse.java

@@ -0,0 +1,31 @@
+/* 
+ * Copyright (c) SKU 다시입을Lab 
+ */
+package com.sku.refit.domain.chat.dto.response;
+
+import java.time.LocalDateTime;
+
+import io.swagger.v3.oas.annotations.media.Schema;
+import lombok.Builder;
+import lombok.Getter;
+
+@Getter
+@Builder
+@Schema(title = "ChatRoomResponse DTO", description = "채팅방 응답 반환")
+public class ChatRoomResponse {
+
+  @Schema(description = "채팅방 식별자", example = "1")
+  private Long roomId;
+
+  @Schema(description = "교환글 식별자", example = "1")
+  private Long exchangePostId;
+
+  @Schema(description = "수신자 닉네임", example = "김재생")
+  private String receiverNickname;
+
+  @Schema(description = "마지막 메세지", example = "내일 오후 1시에 가능합니다!")
+  private String lastMessage;
+
+  @Schema(description = "마지막 메세지 작성 시간", example = "20250101T120000")
+  private LocalDateTime lastMessageAt;
+}

src/main/java/com/sku/refit/domain/chat/entity/ChatMessage.java

@@ -0,0 +1,55 @@
+/* 
+ * Copyright (c) SKU 다시입을Lab 
+ */
+package com.sku.refit.domain.chat.entity;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.Table;
+
+import com.sku.refit.domain.user.entity.User;
+import com.sku.refit.global.common.BaseTimeEntity;
+
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Entity
+@Getter
+@Builder
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@AllArgsConstructor
+@Table(name = "chat_message")
+public class ChatMessage extends BaseTimeEntity {
+
+  @Id
+  @GeneratedValue(strategy = GenerationType.IDENTITY)
+  private Long id;
+
+  @ManyToOne(fetch = FetchType.LAZY)
+  @JoinColumn(name = "chat_room_id", nullable = false)
+  private ChatRoom chatRoom;
+
+  @ManyToOne(fetch = FetchType.LAZY)
+  @JoinColumn(name = "sender_id", nullable = false)
+  private User sender;
+
+  @Column(nullable = false)
+  private String content;
+
+  @Column(nullable = false)
+  @Builder.Default
+  private Boolean isRead = false;
+
+  @Column(nullable = false)
+  @Builder.Default
+  private Boolean isDeleted = false;
+}

src/main/java/com/sku/refit/domain/chat/entity/ChatRoom.java

@@ -0,0 +1,74 @@
+/* 
+ * Copyright (c) SKU 다시입을Lab 
+ */
+package com.sku.refit.domain.chat.entity;
+
+import java.time.LocalDateTime;
+
+import jakarta.persistence.Column;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.GeneratedValue;
+import jakarta.persistence.GenerationType;
+import jakarta.persistence.Id;
+import jakarta.persistence.JoinColumn;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.Table;
+import jakarta.persistence.UniqueConstraint;
+
+import com.sku.refit.domain.exchange.entity.ExchangePost;
+import com.sku.refit.domain.user.entity.User;
+import com.sku.refit.global.common.BaseTimeEntity;
+
+import lombok.AccessLevel;
+import lombok.AllArgsConstructor;
+import lombok.Builder;
+import lombok.Getter;
+import lombok.NoArgsConstructor;
+
+@Entity
+@Getter
+@Builder
+@NoArgsConstructor(access = AccessLevel.PROTECTED)
+@AllArgsConstructor
+@Table(
+    name = "chat_room",
+    uniqueConstraints = {
+      @UniqueConstraint(columnNames = {"exchange_post_id", "sender_id", "receiver_id"})
+    })
+public class ChatRoom extends BaseTimeEntity {
+
+  @Id
+  @GeneratedValue(strategy = GenerationType.IDENTITY)
+  private Long id;
+
+  @ManyToOne(fetch = FetchType.LAZY)
+  @JoinColumn(name = "exchange_post_id", nullable = false)
+  private ExchangePost exchangePost;
+
+  @ManyToOne(fetch = FetchType.LAZY)
+  @JoinColumn(name = "sender_id", nullable = false)
+  private User sender;
+
+  @ManyToOne(fetch = FetchType.LAZY)
+  @JoinColumn(name = "receiver_id", nullable = false)
+  private User receiver;
+
+  @Column(columnDefinition = "TEXT")
+  @Builder.Default
+  private String lastMessage = null;
+
+  @Column @Builder.Default private LocalDateTime lastMessageAt = LocalDateTime.now();
+
+  @Column @Builder.Default private LocalDateTime senderLastReadAt = LocalDateTime.now();
+
+  @Column @Builder.Default private LocalDateTime receiverLastReadAt = LocalDateTime.now();
+
+  public void markAsRead(Long userId, LocalDateTime time) {
+    if (sender.getId().equals(userId)) {
+      this.senderLastReadAt = time;
+    } else {
+      this.receiverLastReadAt = time;
+    }
+  }
+}

src/main/java/com/sku/refit/domain/chat/exception/ChatErrorCode.java

@@ -0,0 +1,22 @@
+/* 
+ * Copyright (c) SKU 다시입을Lab 
+ */
+package com.sku.refit.domain.chat.exception;
+
+import org.springframework.http.HttpStatus;
+
+import com.sku.refit.global.exception.model.BaseErrorCode;
+
+import lombok.AllArgsConstructor;
+import lombok.Getter;
+
+@Getter
+@AllArgsConstructor
+public enum ChatErrorCode implements BaseErrorCode {
+  CHAT_NOT_FOUND("CHAT001", "채팅이 존재하지 않습니다.", HttpStatus.NOT_FOUND),
+  ;
+
+  private final String code;
+  private final String message;
+  private final HttpStatus status;
+}