Spring MVC multiple file upload with HTML5 multiple file form feature

Question

I am trying to upload multiple files using spring 3.1.2 with @Controller and @RequestMapping.

Here\'s what I did and my configuration.

Html5 form :

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Answer 1

Have included commons-fileupload dependency?

<dependency>
  <groupId>commons-fileupload</groupId>
  <artifactId>commons-fileupload</artifactId>
  <version>1.3</version>
</dependency>

I tested the fileupload works fine even with ArrayList as the parameter type on the controller handler

Answer 2

Although you've already gotten your answer thanks to Alex, I'd just like to elaborate a bit. With Spring binding, form fields are bound to their "name" attributes in the HTML. Since it is impossible to have a form field named files[] (if one declares a variable name with that syntax, its name is files, but it is an array of the declaring type), Spring couldn't match it up - and the behavior in that case is to disregard the data in the request.

Using a type such as MultipartFile, you can use either a List named "files" or an array as the following examples:

private List<MultipartFile> files;
private MultipartFile[] files;

With appropriate getters and setters, you can then access and mutate the file list accordingly.