First, the file upload
File upload project development is one of the most common functions, springMVC can be a good support file uploads, but SpringMVC default context is not equipped MultipartResolver, therefore by default it can not handle file uploads work
If you want to use Spring file upload function, you need to configure MultipartResolver in context
1, the configuration file and the guide packet
For springmvc-servlet.xml profiling
1 <! - File Upload Configuration -> 2 <the bean ID = "the MultipartResolver" . 3 class = "org.springframework.web.multipart.commons.CommonsMultipartResolver"> . 4 <Property name = "defaultEncoding" value = "UTF-. 8 "/> 5 <! - upload file size limit in bytes (= 10485760 1OM) -> . 6 <Property name =" maxUploadSize "value =" 1048576 "/> . 7 <Property name =" maxInMemorySize "value = "40960" /> . 8 </ the bean>
2, the front end upload.jsp
In order to upload a file, the form must be set to POST method, and enctype to multipart / form-data; Only in this case, the browser will be selected by the user to the file server to send the binary data
1 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 2 <html> 3 <body> 4 5 <form action="${pageContext.request.contextPath}/upload1" 6 enctype="multipart/form-data" method="post"> 7 <p> 上传 文件：<input type="file" name="file"/></p> 8 <p><input type="submit" value="上传"></p> 9 </form> 10 11 </body> 12 </html>
(1) by way stream of uploaded files
@RequestParam ( "file") the package name = file controls the resulting file into CommonsMultipartFile objects; arrays can be compared to bulk upload CommonsMultipartFile
CommonsMultipartFile common methods:
- String getOriginalFilename (): Gets formerly known as uploading files
- InputStream getInputStream (): Gets file stream
- void transferTo (File dest): Save the file to upload a file directory
Code
. 1 @Controller 2 public class ControllerUpload { . 3 . 4 @RequestMapping ( "/ upload1" ) . 5 public String fileUpload (@RequestParam ( "File" ) CommonsMultipartFile File, . 6 the HttpServletRequest Request) throws IOException { . 7 . 8 // 1. Get the name of the file 9 uploadName = String file.getOriginalFilename (); 10 // 2. If the file name is null is returned home . 11 IF ( "" .equals (uploadName)) { 12 is return "the redirect: /index.jsp"; 13 is } 14 System.out.println ( "upload file name:" + uploadName); 15 16 // 3. Upload path to save settings . 17 . Request.getServletContext String path = () the getRealPath ( "/ the WEB-INF / upload1 " ); 18 // 4. If a path does not exist is created . 19 File realpath = new new File (path); 20 is IF (! realPath.exists ()) { 21 is realPath.mkdir (); 22 is } 23 is the System.out. println ( "save path name:" + realpath); 24 25 // 5. the file input stream 26 InputStream in = file.getInputStream(); 27 //6.文件输入流 28 FileOutputStream out = new FileOutputStream(new File(realPath, uploadName)); 29 30 //7.读取 31 int len = 0; 32 byte[] bytes = new byte[1024]; 33 while ((len = in.read(bytes)) != -1) { 34 out.write(bytes, 0, len); 35 out.flush(); 36 } 37 out.close(); 38 in.close(); 39 40 return "redirect:/success.jsp"; 41 } 42 }
Run the test
Saved location
(2) the use of file.Transto to upload
Code
1 @Controller 2 public class ControllerUpload { 3 4 @RequestMapping("/upload2") 5 public String fileUpload2(@RequestParam("file") CommonsMultipartFile file, 6 HttpServletRequest request) throws IOException { 7 8 //上传路径保存设置 9 String path = request.getServletContext().getRealPath("/WEB-INF/upload2"); 10 File realPath = new File(path); 11 if (!realPath.exists()) { 12 is realPath.mkdir (); 13 is } 14 15 // upload file address 16 System.out.println ( "Upload File Save Address:" + realpath); . 17 18 is // write files directly by the method of CommonsMultipartFile (note that this time) . 19 file.transferTo ( new new File (realpath + "/" + file.getOriginalFilename ())); 20 is 21 is return "the redirect: /success.jsp" ; 22 is } 23 is }
[Note point: Here we have two ways to display a successful upload interface, the first one is like me, a successful new success .jsp;
Then after a successful upload to redirect to a successful interface. The second is to run JSON, plus @ResponseBody in the controller, and return a sentence, so after a successful upload will be displayed directly if you return]
Second, file download
1, the front download.jsp
1 <%@ page contentType="text/html;charset=UTF-8" language="java" %> 2 <html> 3 <body> 4 5 <a href="${pageContext.request.contextPath}/download">下载图片</a> 6 7 </body> 8 </html>
2, controller codes
- Response in response to the first set
- Read a file - InputStream
- Write files - OutputStream
- Perform an operation
- Close stream (the first switch)
. 1 @Controller 2 public class ControllerDownload { . 3 . 4 @RequestMapping ( "/ downloads" ) . 5 public String Downloads (the HttpServletResponse Response) throws Exception { . 6 . 7 // 1. address to download the image . 8 String path = "F.: \\ images " ; . 9 String fileName =" 9.jpg " ; 10 . 11 // 2. set response response header 12 is response.reset (); // set the page is not cached, empty buffer 13 is response.setCharacterEncoding (" UTF-. 8 "); // character encoding 14 the response.setContentType ( "multipart / form-Data"); // binary transmission data 15 // 3. Set response header 16 response.setHeader ( "the Content-Disposition" , . 17 "Attachment; fileName =" + the URLEncoder.encode ( fileName, "UTF-. 8" )); 18 is . 19 file file = new new file (path, fileName); 20 is // 4. read the file - the input stream 21 is the InputStream iNPUT = new new the FileInputStream (file); 22 is // . 5. write file - output stream 23 is the OutputStream OUT = response.getOutputStream (); 24 25 byte[] buff =new byte[1024]; 26 int index=0; 27 //6.执行 写出操作 28 while((index= input.read(buff))!= -1){ 29 out.write(buff, 0, index); 30 out.flush(); 31 } 32 out.close(); 33 input.close(); 34 return null; 35 } 36 }
Run the test
