使用 JAVA 中的 REST API 将文件在线上传到 Sharepoint

Question

I am new to sharepoint rest API and am facing some issue while upload a file(image, document, pdf etc.,) to sharepoint online. Thanks in advance.

The below is our requirement.

1. User will upload the document which are stored at a particular location in application server.

2. A cron job will be running on application server and push the documents to share point online depend upon business needs.

To achieve it, we follow the below steps.

1. Authentication done via AZURE access token (We have used client credential flow to get access token from AZURE AD and able to communicate with sahrepoint online with access token.)

2. We have consumed the sharepoint online REST API to do file operation like upload, download etc,. using java code.

Here we are able to download the file from sharepoint online but when we upload the file, we are getting response as "BAD REQUEST" and status code is "400"

Sharepoint online rest API to create a file:

url: http://site url/_api/web/GetFolderByServerRelativeUrl('/Folder Name')/Files/add(url='a.txt',overwrite=true)
method: POST
body: "Contents of file"
Headers: 
    Authorization: "Bearer " + accessToken
    X-RequestDigest: form digest value
    content-length:length of post body

My Java code :

            //Create HttpURLConnection
            String token ="js#1ikssj......RDS2" // This is just sample
            String request = "Create a File with raw string !!!";
            java.net.URL url = new java.net.URL("http://site url/_api/web/GetFolderByServerRelativeUrl('/Folder Name')/Files/add(url='a.txt',overwrite=true)");
            java.net.URLConnection connection = url.openConnection();
            java.net.HttpURLConnection httpConn = (java.net.HttpURLConnection) connection;
            //Set Header
            httpConn.setDoOutput(true);
            httpConn.setDoInput(true);        
            httpConn.setRequestMethod("POST");                                                  
            httpConn.setRequestProperty("Authorization", "Bearer " +token);                                                                                       
          httpConn.setRequestProperty ("Accept", "application/json;odata=verbose");       
            httpConn.setRequestProperty("binaryStringRequestBody", "true");                                                          
            //Send Request
            java.io.DataOutputStream wr = new java.io.DataOutputStream(httpConn.getOutputStream ());                                                   
            wr.writeBytes(request);
            wr.flush();
            wr.close();
              //Read the response.
            String StatusMessage = "HTTP ResponseCode: " + httpConn.getResponseCode() + " "+  httpConn.getResponseMessage();            

Response : 400 - BAD REQUEST.

Answer 1

You can take a look of this project where you can find a working implementation of uploading files, creating folders, managing folder user permissions and more. It's a very easy to use API with most common operations of the rest API

https://github.com/kikovalle/PLGSharepointRestAPI-java