feat:【站内信】

backend/src/main/java/com/openisle/dto/ConversationDetailDto.java

@@ -0,0 +1,13 @@
+package com.openisle.dto;
+
+import lombok.Data;
+import org.springframework.data.domain.Page;
+
+import java.util.List;
+
+@Data
+public class ConversationDetailDto {
+    private Long id;
+    private List<UserSummaryDto> participants;
+    private Page<MessageDto> messages;
+}

backend/src/main/java/com/openisle/dto/ConversationDto.java

@@ -0,0 +1,17 @@
+package com.openisle.dto;
+
+import lombok.Getter;
+import lombok.Setter;
+
+import java.time.LocalDateTime;
+import java.util.List;
+
+@Getter
+@Setter
+public class ConversationDto {
+    private Long id;
+    private MessageDto lastMessage;
+    private List<UserSummaryDto> participants;
+    private LocalDateTime createdAt;
+    private long unreadCount;
+}

backend/src/main/java/com/openisle/dto/CreateConversationRequest.java

@@ -0,0 +1,8 @@
+package com.openisle.dto;
+
+import lombok.Data;
+
+@Data
+public class CreateConversationRequest {
+    private Long recipientId;
+}

backend/src/main/java/com/openisle/dto/CreateConversationResponse.java

@@ -0,0 +1,12 @@
+package com.openisle.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class CreateConversationResponse {
+    private Long conversationId;
+}

backend/src/main/java/com/openisle/dto/MessageDto.java

@@ -0,0 +1,13 @@
+package com.openisle.dto;
+
+import lombok.Data;
+import java.time.LocalDateTime;
+
+@Data
+public class MessageDto {
+    private Long id;
+    private String content;
+    private UserSummaryDto sender;
+    private Long conversationId;
+    private LocalDateTime createdAt;
+}

backend/src/main/java/com/openisle/dto/UserSummaryDto.java

@@ -0,0 +1,10 @@
+package com.openisle.dto;
+
+import lombok.Data;
+
+@Data
+public class UserSummaryDto {
+    private Long id;
+    private String username;
+    private String avatar;
+}