Upload demo guide

The refreshed upload flow is deliberately safer for demo use. It shows multipart binding and metadata capture without persisting files.

Core binding fields

• File upload for the primary file object.
• String uploadFileName for the original filename.
• String uploadContentType for the MIME type.
• Optional lists for multiple files.

public class FileUploadAction extends ActionSupport {
    private File upload;
    private String uploadFileName;
    private String uploadContentType;

    public String execute() {
        // demo keeps metadata only
        return SUCCESS;
    }
}