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Today, the editor will share with you the relevant knowledge points about how to upload and download files through Spring MVC. The content is detailed and the logic is clear. I believe most people still know too much about this knowledge, so share this article for your reference. I hope you can get something after reading this article.

File upload

1. Import mainly depends on

Commons-fileupload commons-fileupload 1.3.3 javax.servlet javax.servlet-api 4.0.1

2. Configure bean:multipartResolver (Note: the id of this bena must be: multipartResolver, otherwise uploading the file will report a 400th error! )

3 、 index.jsp

4 、 Controller

@ RestControllerpublic class FileController {/ / @ RequestParam ("file") encapsulates the files obtained by the name=file control into CommonsMultipartFile objects / / batch upload CommonsMultipartFile can be an array @ RequestMapping ("/ upload") public String fileUpload (@ RequestParam ("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {/ / get the file name: file.getOriginalFilename (); String uploadFileName = file.getOriginalFilename (); / / if the file name is empty, go straight back to the home page! If (".equals (uploadFileName)) {return" redirect:/index.jsp ";} System.out.println (" upload file name: "+ uploadFileName); / / upload path save settings String path = request.getServletContext (). GetRealPath (" / upload "); / / if the path does not exist, create a File realPath = new File (path) If (! realPath.exists ()) {realPath.mkdir ();} System.out.println ("upload File Save address:" + realPath); InputStream is = file.getInputStream (); / / File input stream OutputStream os = new FileOutputStream (new File (realPath, uploadFileName)); / / File output stream / / read and write int len = 0 Byte [] buffer = new byte [1024]; while ((len = is.read (buffer))! =-1) {os.write (buffer, 0, len); os.flush ();} os.close (); is.close (); return "redirect:/index.jsp" } / * * use file.Transto to save uploaded files * / @ RequestMapping ("/ upload2") public String fileUpload2 (@ RequestParam ("file") CommonsMultipartFile file, HttpServletRequest request) throws IOException {/ / upload path save settings String path = request.getServletContext () .getRealPath ("/ upload"); File realPath = new File (path) If (! realPath.exists ()) {realPath.mkdir ();} System.out.println ("upload file save address:" + realPath); / / write the file directly by CommonsMultipartFile (note this time) file.transferTo (new File (realPath + "/" + file.getOriginalFilename ()); return "redirect:/index.jsp";}}

File download

Index.jsp

Controller

@ RequestMapping (value = "/ download") public String downloads (HttpServletResponse response, HttpServletRequest request) throws Exception {/ / the address of the image to be downloaded is String path = request.getServletContext () .getRealPath ("/ upload"); String fileName = "basic syntax .jpg"; / / 1. Set the response response header response.reset (); / / set the page not to cache, clear buffer response.setCharacterEncoding ("UTF-8") / / character encoding response.setContentType ("multipart/form-data"); / / binary transfer data / / set response header response.setHeader ("Content-Disposition", "attachment;fileName=" + URLEncoder.encode (fileName, "UTF-8")); File file = new File (path, fileName); / / 2, read file-input stream InputStream input = new FileInputStream (file) / / 3. Write out file-output stream OutputStream out = response.getOutputStream (); byte [] buff = new byte [1024]; int index = 0; / / 4. Perform write operation while ((index = input.read (buff))! =-1) {out.write (buff, 0, index); out.flush ();} out.close (); input.close (); return null } these are all the contents of the article "how to upload and download files through Spring MVC". Thank you for reading! I believe you will gain a lot after reading this article. The editor will update different knowledge for you every day. If you want to learn more knowledge, please pay attention to the industry information channel.

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