Springboot file Upload, download, set size

The version of this article using Springboot is 2.0.3.RELEASE

1. Upload a single file

①html the corresponding submission form

 <formAction= "UploadFile"Method= "POST"enctype= "Multipart/form-data">        <P>Select File:<inputtype= "File"name= "FileName"/></P>        <P><inputtype= "Submit"value= "Submit"/></P> </form>

The processing code in ②boot. It's important to note

@RequestMapping ("/uploadfile") corresponds to action= "UploadFile"

@RequestParam ("filename") corresponds to name= "filename"

@RequestMapping ("/uploadfile") @ResponseBody PublicString UploadFile (@RequestParam ("FileName") multipartfile file) {//determine if the file is empty        if(File.isempty ()) {return"-1"; } String fileName=File.getoriginalfilename (); //add a timestamp and try to avoid duplicate file namesString Path = "d:/" +NewSimpleDateFormat ("Yyyymmddhhmmss"). Format (NewDate ()) + "_" +FileName; File dest=NewFile (path); //determine if the file already exists        if(Dest.exists ()) {return"-2"; }        //determine if the file parent directory exists        if(!Dest.getparentfile (). exists ())        {Dest.getparentfile (). mkdir (); }        Try{File.transferto (dest);//Save File}Catch(IOException e) {return"-3"; }        return"0"; }

2. Uploading Multiple Files

①html the corresponding submission form

    <formAction= "Uploadmultifile"Method= "POST"enctype= "Multipart/form-data" >        <P>Select File 1:<inputtype= "File"name= "FileName"/></P>        <P>Select File 2:<inputtype= "File"name= "FileName"/></P>        <P>Select File 3:<inputtype= "File"name= "FileName"/></P>        <P><inputtype= "Submit"value= "Submit"/></P>    </form>

The processing code in ②boot.

    @RequestMapping ("/uploadmultifile")    @ResponseBody    public String keywordsubmitfile (@ Requestparam ("FileName") list<multipartfile> files) {        for  (multipartfile file:files ) {            // Here is a simple output file name             System.out.println (File.getoriginalfilename ());        }         return "0";    }

3. Download the file

@RequestMapping ("/downloadfile") @ResponseBody PublicString DownloadFile (httpservletresponse response, @RequestParam ("FileName") String filepathname) {File file=NewFile (filepathname); if(!file.exists ()) {            return"-1";        } response.reset (); Response.setheader ("Content-disposition", "attachment;filename=" +filepathname); Try{InputStream instream=NewFileInputStream (filepathname); OutputStream OS=Response.getoutputstream (); byte[] Buff =New byte[1024]; intLen =-1;  while(len = instream.read (buff)) > 0) {os.write (buff,0, Len);            } os.flush ();            Os.close ();        Instream.close (); } Catch(Exception e) {e.printstacktrace (); return"-2"; }        return"0"; }

4. Set the upload download file size

① depending on the version, the corresponding setting value is different

Spring Boot 1.3.x and earlier

• multipart.maxFileSize
• multipart.maxRequestSize

Spring Boot 1.4.x and 1.5.x

• spring.http.multipart.maxFileSize
• spring.http.multipart.maxRequestSize

Spring Boot 2.x

• spring.servlet.multipart.maxFileSize
• spring.servlet.multipart.maxRequestSize

② For example, in the 2.x version, set the 30MB size in the project's Application.properties file

spring.servlet.multipart.maxfilesize=30mbspring.servlet.multipart.maxrequestsize=30MB

If you do not limit the size, set to 1

Spring.servlet.multipart.maxfilesize=-1spring.servlet.multipart.maxRequestSize=-1

Reference:

Spring Boot Primer-File upload and download

"I am trying to set maxfilesize but it's not honored"

Above.

Springboot file Upload, download, set size