上传文件： 1.在 `pom.xml` 文件中添加依赖：
xml
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-thymeleaf</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-tomcat</artifactId>
<scope>provided</scope>
</dependency>
<dependency>
<groupId>org.apache.commons</groupId>
<artifactId>commons-fileupload</artifactId>
<version>1.3.3</version>
</dependency>
2.编写上传页面，例如在 `upload.html` 文件中：
html
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>文件上传</title>
</head>
<body>
<form action="/upload" method="post" enctype="multipart/form-data">
<div>
<label for="file">选择文件: </label>
<input type="file" id="file" name="file"/>
</div>
<div>
<input type="submit" value="上传"/>
</div>
</form>
</body>
</html>
3.编写上传逻辑
@Controller
public class FileController {
@RequestMapping("/upload")
public String upload(@RequestParam("file") MultipartFile file,
RedirectAttributes redirectAttributes) {
if (file.isEmpty()) {
redirectAttributes.addFlashAttribute("message", "请选择一个文件上传！");
return "redirect:/";
}
try {
byte[] bytes = file.getBytes();
Path path = Paths.get(file.getOriginalFilename());
Files.write(path, bytes);
redirectAttributes.addFlashAttribute("message", "上传成功！");
} catch (IOException e) {
e.printStackTrace();
}
return "redirect:/";
}
}
下载文件： 1.创建一个接口，用于下载文件。
@Controller
public class FileDownloadController {
@Autowired
private ServletContext servletContext;
/**
* 下载文件
*/
@GetMapping("/download")
public ResponseEntity<Resource> downloadFile(@RequestParam(defaultValue = "") String fileName) throws Exception {
if (fileName.isEmpty()) {
returnbuild();
String filePath Resource resource);
if (!resource.exists()) {
return ResponseEntity.status(HttpStatus.NOT_FOUND).build();
}
String contentType = servletContext.getMimeType(resource.getFile().getAbsolutePath());
return ResponseEntity.ok()
.contentType(MediaType.parseMediaType(contentType))
.header(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\"" + resource.getFilename() + "\"")
.body(resource);
}
}
2.在 `application.properties` 文件中添加如下配置或在配置文件中指定下载文件目录:
properties
spring.servlet.multipart.max-file-size=10MB
spring.servlet.multipart.max-request-size=10MB
file.upload-dir=/path/to/upload/files/
3.在 `application.properties` 中开启下载目录访问：
properties
spring.mvc.static-path-pattern=/download/**
spring.resources.static-locations=file:/path/to/upload/files/
4.编写 download.html 页面：
html
<!DOCTYPE html>
<html xmlns:th="http://www.thymeleaf.org">
<head>
<meta charset="UTF-8">
<title>文件下载</title>
</head>
<body>
<form action="/download" method="get">
<label for="filename">文件名: </label>
<input type="text" id="filename" name="fileName"/>
<button type="submit">下载</button>
</form>
</body>
</html>
5.在 `index.html` 页面添加下载链接：
html
<a href="/download">下载文件</a>
这样，我们就实现了文件上传和下载的功能。
参考文章：http://blog.ncmem.com/wordpress/2023/12/05/%e4%bd%bf%e7%94%a8springboot%e5%ae%9e%e7%8e%b0%e6%96%87%e4%bb%b6%e4%b8%8a%e4%bc%a0%e5%92%8c%e4%b8%8b%e8%bd%bd/
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