Spring Cloud微服务项目文件上传/下载

在现代的微服务架构中，文件上传与下载是常见的需求，尤其是在需要处理大量文件数据的系统中。Spring Cloud 提供了灵活的工具和组件，使得在微服务中实现文件上传和下载变得高效而简便。

本文博主将详细介绍如何在 Spring Cloud 微服务项目中实现文件上传和下载功能。

前置条件

在开始本文前，博主希望你已经初步创建了一个Spring Cloud微服务项目：Spring Cloud微服务项目创建请参考：Spring Cloud微服务项目搭建

1.添加依赖

在子模块的 pom.xml 中添加必要的依赖(博主这里是 order 模块)：

<!-- oder 模块 pom.xml 配置文件 --><dependency><groupId>org.springframework.boot</groupId><artifactId>spring-boot-starter-web</artifactId>
</dependency>

2.配置上传文件的大小限制

在 application.properties 或 application.yml 中配置文件上传的大小限制：

# application.properties 配置文件spring.servlet.multipart.max-file-size=10MB
spring.servlet.multipart.max-request-size=10MB

或

# application.yml 配置文件spring:servlet:multipart:max-file-size: 10MBmax-request-size: 10MB

3.编写Service和Controller层

3.1.创建文件上传方法

博主这里将MyBati 跟 MyBatis-Plus 二者结合一起使用，详情请参考：Spring Cloud微服务项目集成MyBatis

java">@Service
public class OrderService extends ServiceImpl<OrderMapper, OrderInfoModel> {/*** 文件上传*/public String uploadFile(MultipartFile file) {if (file.isEmpty()) {return "上传文件不能为空!";} else {try {// 创建目录String uploadDir = "files/";File dir = new File(uploadDir);if (!dir.exists()) {boolean created = dir.mkdirs();if (!created) {return "Failed to create upload directory.";}}// 获取文件名String fileName = file.getOriginalFilename();Path path = Paths.get(uploadDir + fileName);// 将文件保存到目标路径Files.write(path, file.getBytes());// 返回 文件存储路径return "http://localhost:8000/api/auth/files/" + fileName;} catch (IOException e) {throw new RuntimeException(e);}}}
}

3.2.编写文件上传接口

这里Swagger接口文档请参考：Spring Cloud微服务项目聚合Swagger文档

java">@RestController
@RequestMapping("/api/auth/order")
@Tag(name = "订单管理")
public class OrderController {private final OrderService orderService;@Autowiredpublic OrderController(OrderService orderService) {this.orderService = orderService;}@PostMapping("/uploadFile")@Operation(summary = "文件上传", parameters = {@Parameter(name = "Authorization",description = "TOKEN",in = ParameterIn.HEADER,required = true,schema = @Schema(type = "string"))})public String uploadFile(@RequestParam("file") MultipartFile file) {return orderService.uploadFile(file);}
}

3.3.创建文件下载方法

java">@Service
public class OrderService extends ServiceImpl<OrderMapper, OrderInfoModel> {/*** 文件上传*/public String uploadFile(MultipartFile file) {if (file.isEmpty()) {return "上传文件不能为空!";} else {try {// 创建目录String uploadDir = "files/";File dir = new File(uploadDir);if (!dir.exists()) {boolean created = dir.mkdirs();if (!created) {return "Failed to create upload directory.";}}// 获取文件名String fileName = file.getOriginalFilename();Path path = Paths.get(uploadDir + fileName);// 将文件保存到目标路径Files.write(path, file.getBytes());// 返回 文件存储路径return "http://localhost:8000/api/auth/files/" + fileName;} catch (IOException e) {throw new RuntimeException(e);}}}/*** 文件下载*/public ResponseEntity<Resource> downloadFile(String fileName) {try {// 构建文件路径Path filePath = fileStorageLocation.resolve(fileName).normalize();Resource resource = new UrlResource(filePath.toUri());// 检查文件是否存在if (!resource.exists()) {return ResponseEntity.notFound().build();}// 设置响应头，触发下载String contentType = "application/octet-stream"; // 默认的 MIME 类型return ResponseEntity.ok().contentType(org.springframework.http.MediaType.parseMediaType(contentType)).header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + resource.getFilename() + "\"").body(resource);} catch (Exception e) {return ResponseEntity.status(500).build();}
}

3.4.创建文件下载接口

java">@RestController
@RequestMapping("/api/auth/order")
@Tag(name = "订单管理")
public class OrderController {private final OrderService orderService;@Autowiredpublic OrderController(OrderService orderService) {this.orderService = orderService;}@PostMapping("/uploadFile")@Operation(summary = "文件上传", parameters = {@Parameter(name = "Authorization",description = "TOKEN",in = ParameterIn.HEADER,required = true,schema = @Schema(type = "string"))})public String uploadFile(@RequestParam("file") MultipartFile file) {return orderService.uploadFile(file);}@GetMapping("/download/{fileName:.+}")@Operation(summary = "文件下载", parameters = {@Parameter(name = "Authorization",description = "TOKEN",in = ParameterIn.HEADER,required = true,schema = @Schema(type = "string"))})public ResponseEntity<Resource> downloadFile(@PathVariable String fileName) {return orderService.downloadFile(fileName);}
}