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Apache HttpPost Multiple Files upload failes with server error - Missing initial multi part boundary

I try to upload multiple files, using Apache Http library.
compile group: 'org.apache.httpcomponents', name: 'httpmime', version: '4.5.6'
This is how I upload files.
String url = "url";
File f1 = new File("file1");
File f2 = new File("file2");
HttpPost request = new HttpPost(url);
request.addHeader("Content-Type", "multipart/form-data");
request.addHeader("Authorization", "Basic abcd=");
MultipartEntityBuilder multipartEntityBuilder = MultipartEntityBuilder.create();
multipartEntityBuilder.setMode(HttpMultipartMode.BROWSER_COMPATIBLE);
FileBody fileBody1 = new FileBody(f1, ContentType.DEFAULT_TEXT);
FileBody fileBody2 = new FileBody(f2, ContentType.DEFAULT_TEXT);
multipartEntityBuilder.addPart("file_1_param", fileBody1);
multipartEntityBuilder.addPart("file_2_param", fileBody2);
HttpEntity httpEntity = multipartEntityBuilder.build();
request.setEntity(httpEntity);
HttpClient httpClient = HttpClients.createDefault();
HttpResponse response = httpClient.execute(request);
HttpEntity entity = response.getEntity();
if (entity == null) {
return;
}
InputStream is = entity.getContent();
String textResponse = InputStreamUtils.readText(is);
System.out.println(textResponse);
It prints.
<pre> Server Error</pre></p><h3>Caused by:</h3><pre>java.lang.RuntimeException: javax.servlet.ServletException: org.springframework.web.multipart.MultipartException: Could not parse multipart servlet request; nested exception is java.io.IOException: Missing initial multi part boundary
at com.ca.devtest.acl.servlet.filters.RemoteAuthenticationFilter.doFilter(RemoteAuthenticationFilter.java:285)
at org.eclipse.jetty.servlet.ServletHandler$CachedChain.doFilter(ServletHandler.java:1676)
at org.springframework.web.filter.OncePerRequestFilter.doFilter(OncePerRequestFilter.java:101)
It works if I upload only one file though!
Note, this is not a duplicate. These links show posts which refer the problem on the server side. This problem is with the client side.
Jetty throws "Missing content for multipart request" on multipart form request
500 Internal server error Android HttpPost file upload

I found out a resolution. I wanted to share it with other people, so you can 1) learn how to upload files and 2) pay attention to HTTP headers.
When I append FileBody to MultipartEntityBuilder it automatically sets boundary. I simply removed this line from the code
request.addHeader("Content-Type", "multipart/form-data"); //Remove it
Example of a POST request with one or more files attached
The Multipart Content-Type

Remove the content-type option from the headers completely to make it work.
Example
headers = {
'cache-control': 'no-cache',
'content-type': 'multipart/form-data; boundary=----WebKitFormBoundary7MA4YWxkTrZu0gW',
'postman-token': '26ef68f6-e579-a029-aec2-09b291678b4d',
'storeid': '4223556'
}

use org.apache.http.entity.mime to upload a file to server but can't open it

I use below code to upload a text file to server and it can work.
`HttpPost httppost = new HttpPost(uri+"/uploads.xml");
MultipartEntity mpEntity = new MultipartEntity();
FileBody cbFile = new FileBody(file);
//insertValue
httpclient.getParams().setParameter(CoreProtocolPNames.PROTOCOL_VERSION,HttpVersion.HTTP_1_1);
httpclient.getCredentialsProvider().setCredentials(AuthScope.ANY, defaultcreds);
httppost.setHeader("Content-Type", "application/octet-stream");
mpEntity.addPart("userfile", cbFile);
httppost.setEntity(mpEntity);
//execute
HttpResponse response = httpclient.execute(httppost);`
But when I download the text file from server, I could not open it and find that other messages(the bold text ) be added in the text file.
--RzBVXI2AHuDiIU5UHz-A1jZrpEg6a0JY
Content-Disposition: form-data; name="userfile"; filename="test.txt"
Content-Type: application/octet-stream
Content-Transfer-Encoding: binary
CONTENT...
--RzBVXI2AHuDiIU5UHz-A1jZrpEg6a0JY--
THANKS!

Finally I resolved it.
I use this code
FileEntity entity = new FileEntity(file)
to replace:
FileBody cbFile = new FileBody(file);mpEntity.addPart("userfile", cbFile);
and it works.
But I don't know why....

how to Upload files using MULTIPART file upload in DROPBOX

I am trying to upload files using MULTIPART entity method.But it fails in error says that {"error": "file parameter value 'None' is invalid"}
My code is:
File file = new File("C:/Users/sst-06/Desktop/new.txt");
service.signRequest(dropBoxToken, request);
HttpClient client = new DefaultHttpClient();
String url="https://api-content.dropbox.com/1/files/dropbox/test";
System.out.println("URL "+url);
HttpPost post = new HttpPost(url);
MultipartEntity entity = new MultipartEntity( );
FileBody fileBody= new FileBody( file,"application/x-unknown");
entity.addPart( "file",fileBody);
System.out.println(fileBody);
for (String key : request.getHeaders().keySet()){
post.setHeader(key, request.getHeaders().get(key));
}
post.setEntity( entity );
String response = EntityUtils.toString( client.execute(post).getEntity(), "UTF-8" );
client.getConnectionManager().shutdown();
System.out.println(response);
And my entity file contains all the parameters as mentioned.
--hkYO-pBlK0UQLXjtVKLrBkOSXz7mYe-8WBVBvAnX
Content-Disposition: form-data; name="file"; filename="new.txt"
Content-Type: application/x-unknown
Content-Transfer-Encoding: binary
--File contents--
--hkYO-pBlK0UQLXjtVKLrBkOSXz7mYe-8WBVBvAnX--
I dont know where i felt with error.Please help.
Thanks in advance

Is there any reason why you want to use the web service directly? Will you consider using the DropBox Java SDK?
https://www.dropbox.com/static/developers/dropbox-java-sdk-1.5.3.zip

Http POST in Java (with file upload)

What I want to do is submit a web form from a java application. The form I need to fill out is located here: http://cando-dna-origami.org/
When the form is submitted, the server sends a confirmation email to the email address given, which for now I'm just checking by hand. I've tried filling out the form manually, and the emails get sent fine. (It should also be noted that when the form is filled out incorrectly, the page just refreshes and doesn't give any feedback).
I've never done anything with http before, but I looked around for a while, and came up with the following code, which is supposed to send a POST request to the server:
String data = "name=M+V&affiliation=Company&email="
+ URLEncoder.encode("m.v#gmail.com", "UTF-8")
+ "&axialRise=0.34&helixDiameter=2.25&axialStiffness=1100&bendingStiffness=230" +
"&torsionalStiffness=460&nickStiffness=0.01&resolution=course&jsonUpload="
+ URLEncoder.encode("C:/Users/Marjie/Downloads/twisted_DNA_bundles/monotwist.L1.v1.json",
"UTF-8") + "&type=square";
URL page = new URL("http://cando-dna-origami.org/");
HttpURLConnection con = (HttpURLConnection) page.openConnection();
con.setDoOutput(true);
con.setRequestMethod("POST");
con.connect();
OutputStreamWriter out = new OutputStreamWriter(con.getOutputStream());
out.write(data);
out.flush();
System.out.println(con.getResponseCode());
System.out.println(con.getResponseMessage());
out.close();
con.disconnect();
However, when it runs it doesn't appear to do anything - that is, I don't get any emails, although the program does print "200 OK" to System.out, which seems to indicate that something got received from the server, although I'm not sure what it means exactly. I think the problem might be in the file uploading, since I wasn't sure whether that data type required a different format.
Is this a correct way to send a POST request using Java? Do I need to do something different for the file uploading? Thanks!
After reading Adam's post, I used Apache HttpClient and wrote the following code:
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("type", "square"));
//... add more parameters
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(params, HTTP.UTF_8);
HttpPost post = new HttpPost("http://cando-dna-origami.org/");
post.setEntity(entity);
HttpResponse response = new DefaultHttpClient().execute(post);
post = new HttpPost("http://cando-dna-origami.org/");
post.setEntity(new FileEntity(new File("C:/Users/Marjie/Downloads/twisted_DNA_bundles/monotwist.L1.v1.json"), "text/plain; charset=\"UTF-8\""));
HttpResponse responseTwo = new DefaultHttpClient().execute(post);
However, it still doesn't seem to be working; again, I wasn't sure how the uploaded file fit into the form, so I tried just sending two separate POST requests, one with the form and one with the other data. I am still looking for a way to combine these into one request; does anybody know something about this?

You would probably be better off using something like Apache HttpClient, with which you can build up a POST request programatically.
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://.../whatever");
List <NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("param1", "value1"));
params.add(new BasicNameValuePair("param2", "value2"));
...
httpost.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
HttpResponse response = httpclient.execute(httppost);
If you need to upload a file along with your form, you will need to use a MultipartEntity instead:
MultipartEntity reqEntity = new MultipartEntity();
reqEntity.addPart("someParam", "someValue");
reqEntity.addPart("someFile", new FileBody("/some/file"));
....
httpost.setEntity(reqEntity);
There are some sample programs over on their site. The "Form based logon" and "Multipart encoded request entity" are good examples to start from.
It may also be worthwhile testing out your connections and taking a look at the underlying network data to see what is happening. Something like Firebug will let you see exactly what is happening in your browser, and you can turn up the HttpClient logging to see all of the data exchanged in your program. Alternatively, you can use something like Wireshark or Fiddler to watch your network traffic in real-time. This may give you a better idea of exactly what your browser is doing, versus what your program is doing.

As most of the suggested Java HTTP POST request code out there is not operational, I decided to give you my fully operational code that I'm sure you'll find helpful to create any Java-based POST request in the future.
This POST request is of multipart type to allow sending/uploading a file to the server.
Multipart request consist of a main header and a separator string called boundary to tell each part from the other (this separator will come in the stream with "--" (two dashes) string before it, and each part has its own small header to tell its type and some more meta-data.
My task was to create a PDF file using some online services but all the multipart POST examples just didn't do the trick...
I needed to pack an HTML document along with its pics, JS and CSS files in a ZIP/TAR file, upload it to an online html2pdf conversion service and get the result as a PDF document back to me as the response (stream) from the service.
The current service I've checked the using following code is: Htmlpdfapi.com but I'm sure that with minor adjustments you'll be able to use it with any other service.
The method call (for that service) looks something like:
[class instance name].sendPOSTRequest("http://htmlpdfapi.com/api/v1/pdf", "Token 6hr4-AmqZDrFVjAcJGykjYyXfwG1wER4", "/home/user/project/srv/files/example.zip", "result.pdf");
Here is my code that was checked and 100% works:
public void sendPOSTRequest(String url, String authData, String attachmentFilePath, String outputFilePathName)
{
String charset = "UTF-8";
File binaryFile = new File(attachmentFilePath);
String boundary = "------------------------" + Long.toHexString(System.currentTimeMillis()); // Just generate some unique random value.
String CRLF = "\r\n"; // Line separator required by multipart/form-data.
int responseCode = 0;
try
{
//Set POST general headers along with the boundary string (the seperator string of each part)
URLConnection connection = new URL(url).openConnection();
connection.setDoOutput(true);
connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
connection.addRequestProperty("User-Agent", "CheckpaySrv/1.0.0");
connection.addRequestProperty("Accept", "*/*");
connection.addRequestProperty("Authentication", authData);
OutputStream output = connection.getOutputStream();
PrintWriter writer = new PrintWriter(new OutputStreamWriter(output, charset), true);
// Send binary file - part
// Part header
writer.append("--" + boundary).append(CRLF);
writer.append("Content-Disposition: form-data; name=\"file\"; filename=\"" + binaryFile.getName() + "\"").append(CRLF);
writer.append("Content-Type: application/octet-stream").append(CRLF);// + URLConnection.guessContentTypeFromName(binaryFile.getName())).append(CRLF);
writer.append(CRLF).flush();
// File data
Files.copy(binaryFile.toPath(), output);
output.flush();
// End of multipart/form-data.
writer.append(CRLF).append("--" + boundary + "--").flush();
responseCode = ((HttpURLConnection) connection).getResponseCode();
if(responseCode !=200) //We operate only on HTTP code 200
return;
InputStream Instream = ((HttpURLConnection) connection).getInputStream();
// Write PDF file
BufferedInputStream BISin = new BufferedInputStream(Instream);
FileOutputStream FOSfile = new FileOutputStream(outputFilePathName);
BufferedOutputStream out = new BufferedOutputStream(FOSfile);
int i;
while ((i = BISin.read()) != -1) {
out.write(i);
}
// Cleanup
out.flush();
out.close();
}
catch(Exception e)
{
e.printStackTrace();
}
}

I am currently writing a small web server, and I tested your request client. My server is receiving the following request:
User-Agent: Java/1.6.0_20
Host: localhost:1700
Accept: text/html, image/gif, image/jpeg, *; q=.2, */*; q=.2
Connection: keep-alive
Content-type: application/x-www-form-urlencoded
Content-Length: 287
name=M+V&affiliation=Company&email=m.v%40gmail.com&axialRise=0.34&helixDiameter=2.25&axialStiffness=1100&bendingStiffness=230&torsionalStiffness=460&nickStiffness=0.01&resolution=course&jsonUpload=C%3A%2FUsers%2FMarjie%2FDownloads%2Ftwisted_DNA_bundles%2Fmonotwist.L1.v1.json&type=square
You should check the format of the POST data you are sending, most probably it is not processed by the server as you would expect.

You should definitively use apaches HTTPClient for that job! It makes life much easier. Here is an example how to upload a file with apaches HttpClient.
byte[] data = outStream.toByteArray()
HttpClient client = new DefaultHttpClient();
HttpPost httpPost = new HttpPost("http://localhost:8080/YourResource");
ByteArrayBody byteArrayBody = new ByteArrayBody(data, "application/json", "some.json");
MultipartEntity multipartEntity = new MultipartEntity();
multipartEntity.addPart("upload", byteArrayBody);
httpPost.setEntity( multipartEntity );
HttpResponse response = client.execute(httpPost);
Reader reader = new InputStreamReader(response.getEntity().getContent());
Let me know if you have further questions.

Here's an example I got working that uses apache httpclient. Also, don't forget to add these dependencies:
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.4.1</version>
</dependency>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpmime</artifactId>
<version>4.4.1</version>
</dependency>
The code:
HttpClient httpclient = HttpClientBuilder.create().build();
HttpPost httppost = new HttpPost(DataSources.TORRENT_UPLOAD_URL);
MultipartEntityBuilder builder = MultipartEntityBuilder.create();
builder.addPart("a_field_name", new FileBody(torrentFile));
HttpEntity entity = builder.build();
httppost.setEntity(entity);
HttpResponse response = httpclient.execute(httppost);

Apache HttpClient making multipart form post

I'm pretty green to HttpClient and I'm finding the lack of (and or blatantly incorrect) documentation extremely frustrating. I'm trying to implement the following post (listed below) with Apache Http Client, but have no idea how to actually do it. I'm going to bury myself in documentation for the next week, but perhaps more experienced HttpClient coders could get me an answer sooner.
Post:
Content-Type: multipart/form-data; boundary=---------------------------1294919323195
Content-Length: 502
-----------------------------1294919323195
Content-Disposition: form-data; name="number"
5555555555
-----------------------------1294919323195
Content-Disposition: form-data; name="clip"
rickroll
-----------------------------1294919323195
Content-Disposition: form-data; name="upload_file"; filename=""
Content-Type: application/octet-stream
-----------------------------1294919323195
Content-Disposition: form-data; name="tos"
agree
-----------------------------1294919323195--

Use MultipartEntityBuilder from the HttpMime library to perform the request you want.
In my project I do that this way:
HttpEntity entity = MultipartEntityBuilder
.create()
.addTextBody("number", "5555555555")
.addTextBody("clip", "rickroll")
.addBinaryBody("upload_file", new File(filePath), ContentType.APPLICATION_OCTET_STREAM, "filename")
.addTextBody("tos", "agree")
.build();
HttpPost httpPost = new HttpPost("http://some-web-site");
httpPost.setEntity(entity);
HttpResponse response = httpClient.execute(httpPost);
HttpEntity result = response.getEntity();
Hope this will help.
(Updated this post to use MultipartEntityBuilder instead of deprecated MultipartEntity, using #mtomy code as the example)

MultipartEntity now shows up as deprecated. I am using apache
httpclient 4.3.3 - does anyone know what we are supposed to use
instead? I find the google searches to be so full of MultipartEntity
examples I can't find anything. – vextorspace Mar 31 '14 at 20:36
Here is the sample code in HttpClient 4.3.x
http://hc.apache.org/httpcomponents-client-4.3.x/httpmime/examples/org/apache/http/examples/entity/mime/ClientMultipartFormPost.java
import org.apache.http.entity.mime.MultipartEntityBuilder;
HttpPost httppost = new HttpPost("http://localhost:8080" +
"/servlets-examples/servlet/RequestInfoExample");
FileBody bin = new FileBody(new File(args[0]));
StringBody comment = new StringBody("A binary file of some kind", ContentType.TEXT_PLAIN);
HttpEntity reqEntity = MultipartEntityBuilder.create()
.addPart("bin", bin)
.addPart("comment", comment)
.build();
httppost.setEntity(reqEntity);
To use the class MultipartEntityBuilder, you need httpmime, which is a sub project of HttpClient
HttpClient 4.3.x:
http://hc.apache.org/httpcomponents-client-4.3.x/index.html
httpmime 4.3.x:
http://hc.apache.org/httpcomponents-client-4.3.x/httpmime/dependency-info.html

if use org.apache.commons.httpclient.HttpClient package, maybe that can help you!
HttpConnectionManager httpConnectionManager = new MultiThreadedHttpConnectionManager();
//here should set HttpConnectionManagerParams but not important for you
HttpClient httpClient = new HttpClient(httpConnectionManager);
PostMethod postMethod = new PostMethod("http://localhost/media");
FilePart filePart = new FilePart("file", new File(filepath));
StringPart typePart = new StringPart("type", fileContent.getType(), "utf-8");
StringPart fileNamePart = new StringPart("fileName", fileContent.getFileName(), "utf-8");
StringPart timestampPart = new StringPart("timestamp", ""+fileContent.getTimestamp(),"utf-8");
Part[] parts = { typePart, fileNamePart, timestampPart, filePart };
MultipartRequestEntity multipartRequestEntity = new MultipartRequestEntity(parts, postMethod.getParams());
postMethod.setRequestEntity(multipartRequestEntity);
httpClient.executeMethod(postMethod);
String responseStr = postMethod.getResponseBodyAsString();