Springboot Upload File

Configure the upload path and file limit size in the application.yml configuration file

Spring:
   servlet:
      multipart:
        max-file-size:10kb 
Upload:
   file:
      location:d:\upload\

officially available configurable items:

# MULTIPART (multipartproperties)
Spring.servlet.multipart.enabled=true # Whether to enable support of multipart uploads. Spring.servlet.multipart.file-size-threshold=0 # threshold after which files are written to disk.
Values can use the suffixes ' MB ' or ' KB ' to indicate megabytes or kilobytes, respectively.
Spring.servlet.multipart.location= # Intermediate location of uploaded files. SPRING.SERVLET.MULTIPART.MAX-FILE-SIZE=1MB # max file size.
Values can use the suffixes ' MB ' or ' KB ' to indicate megabytes or kilobytes, respectively. SPRING.SERVLET.MULTIPART.MAX-REQUEST-SIZE=10MB # Max request size.
Values can use the suffixes ' MB ' or ' KB ' to indicate megabytes or kilobytes, respectively. Spring.servlet.multipart.resolve-lazily=false # Whether To resolve the multipart request lazily at the time of file or par
Ameter access. 

Official website Path: https://docs.spring.io/spring-boot/docs/current-SNAPSHOT/reference/htmlsingle/# Howto-multipart-file-upload-configuration

Create an upload request controller

first, use the @value annotation in controller to get the save path to the uploaded file

@Value ("${upload.file.location}")
private String uploadlocation;

Then write the request method

 @PostMapping (value = "/upload") public responseentity<?> upload (httpservletrequest reqquest, @RequestParam ("fil E ") multipartfile file {try {if (File.isempty ()) {return new responseentity<string> (" File is empty ", Httpstatu
		     s.accepted);
			}//string Uploaddir = Resourceutils.geturl ("classpath:"). GetPath ();
			String Uploaddir = Reqquest.getsession (). Getservletcontext (). Getrealpath ("/") + "upload\\";
			String uploaddir = uploadlocation;
			File dir = new file (Uploaddir);
			if (!dir.exists ()) {dir.mkdirs ();
			String filename = File.getoriginalfilename ();
			File Serverfile = new file (uploaddir + filename);
			File.transferto (Serverfile);
		return new Responseentity<string> ("Upload success", Httpstatus.ok);
			catch (IllegalStateException e) {e.printstacktrace ();
		return new responseentity<string> ("Upload failed", httpstatus.accepted);
			catch (IOException e) {e.printstacktrace (); return new responseentity<string> ("Upload failed", Httpstatus.)accepted); }
	}

One thing to note here is that file in @requestparam ("file") must match the name attribute of the HTML upload input, such as

<form action= "Upload" method= "post" enctype= "Multipart/form-data" >
        <p> Select File: <input type= "File" Name= "File"/></p>
        <p><input type= "Submit" value= "submitted"/></p>
</form>

If you need to customize the saved file name, add the following code:

String suffix = filename.substring (Filename.lastindexof ("."));
String definename = uuid.randomuuid () + suffix;

Upload Multiple Files

    @PostMapping (value = "/uploads") public responseentity<?> uploads (HttpServletRequest reqquest, @RequestParam ("File")
		Multipartfile[] files) {//string Uploaddir = Resourceutils.geturl ("classpath:"). GetPath ();
		String Uploaddir = Reqquest.getsession (). Getservletcontext (). Getrealpath ("/") + "upload\\";
		String uploaddir = uploadlocation;
		File dir = new file (Uploaddir);
		if (!dir.exists ()) {dir.mkdirs ();
				for (int i=0;i<files.length;i++) {if (files[i]!= null) {Multipartfile file = Files[i];
				String filename = File.getoriginalfilename ();
				String suffix = filename.substring (Filename.lastindexof ("."));
				String definename = uuid.randomuuid () + suffix;
				File Serverfile = new file (Uploaddir + definename);
				try {File.transferto (serverfile);
					catch (IllegalStateException e) {e.printstacktrace ();
				return new responseentity<string> ("Upload the first" +i+ "File Failure", httpstatus.accepted); catch (IOException e) {E.printstaCktrace ();
				return new responseentity<string> ("Upload the first" +i+ "File Failure", httpstatus.accepted);		
	}} return new Responseentity<string> ("Upload succeeded", Httpstatus.ok); }