引言
文件上传和下载是Web应用开发中常见的功能之一，Spring Boot通过其丰富的生态系统和简化的配置，使得实现这些功能变得非常简单。本文将详细介绍如何在Spring Boot中实现文件的上传和下载，并提供包含cn.juwatech.*包名的Java代码示例。
实现文件上传
1. 添加依赖
首先，需要在您的Spring Boot项目中添加文件上传的依赖。通常，您可以使用以下Maven配置：
<dependency> <groupId>org.springframework.boot</groupId> <artifactId>spring-boot-starter-web</artifactId> </dependency> <dependency> <groupId>commons-fileupload</groupId> <artifactId>commons-fileupload</artifactId> <version>1.4</version> </dependency> <dependency> <groupId>org.apache.commons</groupId> <artifactId>commons-io</artifactId> <version>1.3.2</version> </dependency>
2. 配置文件上传接口
创建一个Controller来处理文件上传请求：
package cn.juwatech.controller; import org.springframework.web.bind.annotation.*; import org.springframework.web.multipart.MultipartFile; import java.io.File; import java.io.IOException; @RestController @RequestMapping("/file") public class FileUploadController { @PostMapping("/upload") public String uploadFile(@RequestParam("file") MultipartFile file) { if (file.isEmpty()) { return "Please select a file to upload."; } try { byte[] bytes = file.getBytes(); File destFile = new File("/path/to/upload/directory/" + file.getOriginalFilename()); FileUtils.writeByteArrayToFile(destFile, bytes); // Ensure commons-io dependency return "File uploaded successfully!"; } catch (IOException e) { return "Failed to upload file: " + e.getMessage(); } } }
实现文件下载
1. 配置文件下载接口
创建一个Controller来处理文件下载请求：
package cn.juwatech.controller; import org.springframework.core.io.Resource; import org.springframework.core.io.UrlResource; import org.springframework.http.HttpHeaders; import org.springframework.http.ResponseEntity; import org.springframework.web.bind.annotation.*; import java.io.File; import java.io.IOException; import java.net.MalformedURLException; import java.nio.file.Path; import java.nio.file.Paths; @RestController @RequestMapping("/file") public class FileDownloadController { @GetMapping("/download/{fileName:.+}") public ResponseEntity<Resource> downloadFile(@PathVariable String fileName) { Path filePath = Paths.get("/path/to/upload/directory/").resolve(fileName).normalize(); Resource resource; try { resource = new UrlResource(filePath.toUri()); if (resource.exists()) { return ResponseEntity.ok() .header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + resource.getFilename() + "\"") .body(resource); } else { return ResponseEntity.notFound().build(); } } catch (MalformedURLException e) { return ResponseEntity.notFound().build(); } } }
示例代码：
以下是一个简单的示例代码，展示了如何在Spring Boot中实现文件的上传和下载：
package cn.juwatech.example; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; @SpringBootApplication public class MyApp { public static void main(String[] args) { SpringApplication.run(MyApp.class, args); } }
结论
通过本文的介绍，我们学习了如何在Spring Boot应用中实现文件的上传和下载功能，包括配置文件上传和下载接口、处理上传和下载请求的Controller等关键步骤。Spring Boot简化了文件操作的实现过程，使得开发者能够更加专注于业务逻辑的实现。
