diff --git a/examples/chapter07/paopao/src/main/java/com/lk/paopao/service/AttachService.java b/examples/chapter07/paopao/src/main/java/com/lk/paopao/service/AttachService.java
new file mode 100644
index 0000000..9d63dde
--- /dev/null
+++ b/examples/chapter07/paopao/src/main/java/com/lk/paopao/service/AttachService.java
@@ -0,0 +1,128 @@
+package com.lk.paopao.service;
+
+import com.lk.paopao.dto.AttachmentDto;
+import com.lk.paopao.entity.Attachment;
+import com.lk.paopao.entity.User;
+import com.lk.paopao.mapper.AttachmentMapper;
+import com.lk.paopao.repository.AttachmentRepository;
+import org.springframework.beans.factory.annotation.Autowired;
+import org.springframework.beans.factory.annotation.Value;
+import org.springframework.stereotype.Service;
+import org.springframework.web.multipart.MultipartFile;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+import java.util.HashMap;
+import java.util.Map;
+import java.util.UUID;
+
+@Service
+public class AttachService {
+
+    // 从配置中获取上传路径
+    @Value("${app.upload.path}")
+    String UPLOAD_DIR;
+
+    // 从配置中获取子路径名长度，用于文件分目录存储
+    @Value("${app.upload.sub-path-name-length}")
+    int SUB_PATH_LENGTH = 1;
+
+    @Autowired
+    AuthService authService;
+    @Autowired
+    AttachmentRepository attachmentRepository;
+    @Autowired
+    AttachmentMapper attachmentMapper;
+
+
+    /**
+     * 上传附件
+     * @param file  文件
+     * @param attachType 附件类型
+     * @return AttachmentDto
+     * @throws IOException 输入输出异常
+     */
+    public AttachmentDto upload(MultipartFile file) throws IOException {
+        // 获取原始文件名
+        String originFileName = file.getOriginalFilename();
+        if(originFileName == null){
+            throw new IllegalArgumentException("没有原始文件名");
+        }
+
+        InputStream inputStream = file.getInputStream();
+        // 获取当前用户
+        User currentUser = authService.getCurrentUser();
+        // 上传文件并获取相对URL
+        String relativeUrl = save(originFileName,inputStream);
+        Attachment attachment = new Attachment();
+        // 设置附件类型
+        attachment.setType(getType(file.getContentType()));
+        // 设置附件内容（即存储的URL）
+        attachment.setContent(relativeUrl);
+        // 关联用户
+        attachment.setUser(currentUser);
+        // 设置文件大小
+        attachment.setFileSize(file.getSize());
+        // 保存附件
+        Attachment savedAttachment = attachmentRepository.save(attachment);
+        // 转换并返回附件DTO
+        return attachmentMapper.toDto(savedAttachment);
+    }
+
+
+    /**
+     * 保存文件到上传目录中
+     * @param fileName 原文件名
+     * @param fileStream 文件流
+     * @return 保存后的文件访问路径
+     * @throws IOException 文件操作异常
+     */
+    public String save(String fileName, InputStream fileStream) throws IOException {
+        // 生成新的文件名以避免重复
+        String rename = UUID.randomUUID().toString();
+        int dotIndex = fileName.lastIndexOf('.');
+        // 新文件名，包含扩展名
+        String newFile = rename+((dotIndex > 0) ? "."+fileName.substring(dotIndex + 1) : "");
+
+        // 根据子路径长度计算文件保存的子目录
+        String subPath = rename.substring(0,SUB_PATH_LENGTH);
+        // 完整的保存路径
+        String uploadPath = UPLOAD_DIR+"/"+subPath;
+
+        // 确保目录存在，不存在则创建
+        Path directory = Paths.get(uploadPath);
+        if (!Files.exists(directory)) {
+            Files.createDirectories(directory);
+        }
+        // 文件的最终保存位置
+        Path targetLocation = Paths.get(uploadPath, newFile);
+        // 复制文件流到目标位置
+        Files.copy(fileStream, targetLocation);
+        // 返回文件的访问路径
+        return "/"+subPath+"/"+newFile;
+    }
+
+    /**
+     * 根据文件的MIME类型返回文件类型标识
+     * @param contentType 文件的MIME类型
+     * @return 文件类型的标识字节，0表示未知类型
+     */
+    public static byte getType(String contentType) {
+
+        if(contentType == null){
+            return 0;
+        }
+        if(contentType.startsWith("image/")){
+            return 1;
+        }
+        if(contentType.startsWith("video/")){
+            return 2;
+        }
+
+        return 3;
+    }
+}
+
diff --git a/examples/chapter07/paopao/src/main/resources/application.yml b/examples/chapter07/paopao/src/main/resources/application.yml
index 096af03..29094d0 100644
--- a/examples/chapter07/paopao/src/main/resources/application.yml
+++ b/examples/chapter07/paopao/src/main/resources/application.yml
@@ -20,4 +20,10 @@ spring:
     defer-datasource-initialization: true
     database-platform: org.hibernate.dialect.H2Dialect
     hibernate:
-      ddl-auto:  update
\ No newline at end of file
+      ddl-auto:  update
+      
+
+app:
+  upload:
+    path: ./upload
+    sub-path-name-length: 1
\ No newline at end of file