How To Create Folder Structure in SharePoint Document Library
[File structure which same to the physical path]
(Data Migration P1)

I was assigned for a data migration task in one of a project. in that project client has a aster file based which hold more that 50,000 files like excel doc and pdf. what he need it upload them into the SharePoint site using console application.
requirement is quite complex so in that case I divided it into 3 parts and will share the things which I think that it'll useful for you also.
Why we need folder structure ?? 
this is not just a data migration we need to create folder path which exactly same to the physical  path of the file which required to migrate. please refer the attachment, below to get a better understanding.

when you consider the yellow highlighted area you can see that the physical file path should be same means inside the document library we need to create [Settlement System -> CES Inputs -> 2011 -> Dawn Gas Prices] directory structure.

How to do that ?? 
to do that I have introduce a function which can create this folder structure.

spServerURL : The URL of the application [Eg: http://myspweb:8000/]

spDocumentLibraryName :  the name of the document library which you need to upload documents or create folder path on top of [Eg : Settlement (which highlighted on blue in above picture)

Filepath : physicle file path of the document (Eg : C:\ThilinaLIB\SAMPLES\Cost and Production\5 Minute Meter Data\File Names - AG and MW - Copy (4).xlsx)

Removablepath : path which remove (no use for migration which highlighted in gray color in above picture) [Eg: C:\ThilinaLIB]

public static void CreateFolder(string spServerURL,string spDocumentLibraryName,string FilePath,string Removablepath)

        {

            try

            {

                SPSite _MySite = new SPSite(spServerURL);

                SPWeb _MyWeb = _MySite.OpenWeb();

                // create document lib object which we use for uploading and creating folder paths

                SPDocumentLibrary _MyDocLibrary = (SPDocumentLibrary)_MyWeb.Lists[spDocumentLibraryName];

                SPFolderCollection _MyFolders = _MyWeb.Folders;

                // create folder path which we need to manipulate inside the document library

                FilePath = FilePath.Replace(Removablepath, "");

                char[] directoryCharSeparators = new char[] { Path.DirectorySeparatorChar };

                string mypath = Path.GetDirectoryName(FilePath);

                // Get the folder structure.

                string[] directories = mypath.Split(directoryCharSeparators, StringSplitOptions.RemoveEmptyEntries);

                // cretae document lib path

                string Target = SPUrlUtility.CombineUrl(_MyWeb.ServerRelativeUrl, spDocumentLibraryName);

                foreach (string item in directories)

                {

                    Target = Target + "/" + item;

                    _MyFolders.Add(Target + "/");

                }

                // folder creation is completed in this point

                _MyDocLibrary.Update();

                           }

            catch (Exception ex)

            {

               

                throw ex;

            }

        }

Let's Move from Line by Line ....
SPDocumentLibrary _MyDocLibrary = (SPDocumentLibrary)_MyWeb.Lists[spDocumentLibraryName];
create document library object which we are going to use to create our folder structure.


SPFolderCollection _MyFolders = _MyWeb.Folders;
Take the existing folder collection. which we are using to add our new folders.


FilePath = FilePath.Replace(Removablepath, "");
This is so important. we need to remove some of part form the original file path. Imaging if the file path is like this "C:\TEMP\SP4RK\compmgmt\compadmn\example.xlsx" but we are going to create folder structure in the document library as following "http://talliance.domainx.local:12345/Settlement/SP4RK/compmgmt/compadmn/" so we need to remove "C:\TEMP" part from the original file path.


string mypath = Path.GetDirectoryName(FilePath);
get only directory or Folder path. Eg : if FilePath = "\SP4RK\compmgmt\compadmn\example.xlsx" The myPath would be "\SP4RK\compmgmt\compadmn"

char[] directoryCharSeparators = new char[] { Path.DirectorySeparatorChar };

                // Get the folder structure.

                string[] directories = mypath.Split(directoryCharSeparators, StringSplitOptions.RemoveEmptyEntries);

Use to take directory names in to the string array in a order so it's like directories = { "SP4RK","compmgmt","compadmn" }

string Target = SPUrlUtility.CombineUrl(_MyWeb.ServerRelativeUrl, spDocumentLibraryName);
we need to create target location which we are going to add the folders. it would be "\Settlement"

foreach (string item in directories)

                {

                    Target = Target + "/" + item;

                    _MyFolders.Add(Target + "/");

                }

This is the most important part using this loop we can create folder path one by one. (FYI: keep one thing in your mind you cannot create full folder path at once means to create  "compadmn" folder ,"SP4RK/compmgmt" should exist and do not worry is one folder is already exsiste and it it contain document inside those will remain even you create same folder again )

 _MyDocLibrary.Update();
Finally you should update the document library.

ok That's It ... 

HAPPY CODING