Getting a path within a controller for file upload directory

[Aron Daburn]

New to Spring here trying to get a file upload. I have everything set up to handle the file, the form, controller, etc. I have it such that the controller gets the actual file, but my problem is now where to have the controller actually write the file to.

How do I get a path such that it will place it in a temp directory to have it available for the rest of the web application? I see an example where it saves to DB, gets a path from the System.properties (which seems bad to me) and then a hard coded value. How do I get a web application variable (relative path to tmp dir) from within the controller class?

package test;

import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RequestParam;
import org.springframework.web.multipart.MultipartFile;

@Controller
public class FileUploadController {

    @RequestMapping(value = "/form", method = RequestMethod.POST)
    public String handleFormUpload(@RequestParam("name") String name, 
        @RequestParam("file") MultipartFile file) {

    	
        if (!file.isEmpty()) {
            
            // store the bytes somewhere
        	System.out.println("Success!");
           return "redirect:upload.html";
       } else {
    	   System.out.println("Failure!");
           return "redirect:upload.html";
       }
    }
}

(Code is just a simple prototype for learning)

[Paul Clapham]

That depends on what you want of the files you're going to put into this directory. For example: are they just temporary work files, or do they need to stay in the directory as part of somebody's session, or are they permanent files which should still be accessible even if your application, or the application server, is restarted?

[Aron Daburn]

They will be "permanent files which should still be accessible even if your application, or the application server, is restarted".

[Paul Clapham]

Okay. Then just create a directory for that purpose and use it.

[Aron Daburn]

I understand that. How do I point the code to said directory? I don't want to hard code a path to that directory into the class. I want it to be configurable by the web app. So how does the web app pass in a variable to the controller class in Spring?