Spring MVC 为文件上传提供了直接的支持,这种支持是通过即插即用的 MultipartResolver 实现的。Spring 用Jakarta Commons FileUpload 技术实现了一个MultipartResolver 实现类:CommonsMultipartResovler
Spring MVC 上下文中默认没有装配 MultipartResovler,因此默认情况下不能处理文件的上传工作,如果想使用 Spring的文件上传功能,需现在上下文中配置 MultipartResolver
defaultEncoding: 必须和用户 JSP 的 pageEncoding 属性一致,以便正确解析表单的内容
为了让 CommonsMultipartResovler 正确工作,必须先将 Jakarta Commons FileUpload 及 Jakarta Commons io的类包添加到类路径下。
配置源代码
<!-- 配置 MultipartResolver -->
<bean id="multipartResolver"
class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
<property name="defaultEncoding" value="UTF-8"></property>
<property name="maxUploadSize" value="1024000"></property>
</bean>
handle 中方法代码
上传
@RequestMapping("/testFileUpload")
public String testFileUpload(@RequestParam("desc") String desc,
@RequestParam("file") MultipartFile file) throws IOException{
System.out.println("desc: " + desc);
System.out.println("OriginalFilename: " + file.getOriginalFilename());
//可以拿到Io流
System.out.println("InputStream: " + file.getInputStream());
return "success";
}
下载
@RequestMapping("/testResponseEntity")
public ResponseEntity<byte[]> testResponseEntity(HttpSession session) throws IOException{
byte [] body = null;
ServletContext servletContext = session.getServletContext();
InputStream in = servletContext.getResourceAsStream("/files/abc.txt");
body = new byte[in.available()];
in.read(body);
HttpHeaders headers = new HttpHeaders();
headers.add("Content-Disposition", "attachment;filename=abc.txt");
HttpStatus statusCode = HttpStatus.OK;
ResponseEntity<byte[]> response = new ResponseEntity<byte[]>(body, headers, statusCode);
return response;
}