springmvc上传与下载
必须导入jar包
如果是maven项目导入依赖包
<!-- 文件上传 --> <dependency> <groupId>commons-fileupload</groupId> <artifactId>commons-fileupload</artifactId> <version>1.3</version> </dependency>
在spring的servlet视图解析器下面定义CommonsMultipartResolver文件解析器,就是加入这个的时候运行项目,如果没有fileuload相关的jar包就会报错。
在spring mvc 的配置文件中书写xml配置
<!-- 定义文件解释器 --> <bean id="multipartResolver" class="org.springframework.web.multipart.commons.CommonsMultipartResolver"> <!-- 设置默认编码 --> <property name="defaultEncoding" value="utf-8"></property> <!-- 上传图片最大大小5M--> <property name="maxUploadSize" value="5242440"></property> </bean>
代码演示
@RequestMapping("file") @Controller public class FileController { /** * 文件上传功能 * @param file * @return * @throws IOException */ @RequestMapping(value="/upload",method=RequestMethod.POST) @ResponseBody public String upload(MultipartFile file,HttpServletRequest request) throws IOException{ String path = request.getSession().getServletContext().getRealPath("upload"); String fileName = file.getOriginalFilename(); File dir = new File(path,fileName); if(!dir.exists()){ dir.mkdirs(); } //MultipartFile自带的解析方法 file.transferTo(dir); return "ok!"; } /** * 文件下载功能 * @param request * @param response * @throws Exception */ @RequestMapping("/down") public void down(HttpServletRequest request,HttpServletResponse response) throws Exception{ //模拟文件,myfile.txt为需要下载的文件 String fileName = request.getSession().getServletContext().getRealPath("upload")+"/myfile.txt"; //获取输入流 InputStream bis = new BufferedInputStream(new FileInputStream(new File(fileName))); //假如以中文名下载的话 String filename = "下载文件.txt"; //转码,免得文件名中文乱码 filename = URLEncoder.encode(filename,"UTF-8"); //设置文件下载头 response.addHeader("Content-Disposition", "attachment;filename=" + filename); //1.设置文件ContentType类型,这样设置,会自动判断下载文件类型 response.setContentType("multipart/form-data"); BufferedOutputStream out = new BufferedOutputStream(response.getOutputStream()); int len = 0; while((len = bis.read()) != -1){ out.write(len); out.flush(); } out.close(); } }