We use HttpClient 4.x to make multipart file post.
UPDATE: As of HttpClient 4.3, some classes have been deprecated. Here is the code with new API:
CloseableHttpClient httpClient = HttpClients.createDefault();
HttpPost uploadFile = new HttpPost("...");
MultipartEntityBuilder builder = MultipartEntityBuilder.create();
builder.addTextBody("field1", "yes", ContentType.TEXT_PLAIN);
// This attaches the file to the POST:
File f = new File("[/path/to/upload]");
builder.addBinaryBody(
"file",
new FileInputStream(f),
ContentType.APPLICATION_OCTET_STREAM,
f.getName()
);
HttpEntity multipart = builder.build();
uploadFile.setEntity(multipart);
CloseableHttpResponse response = httpClient.execute(uploadFile);
HttpEntity responseEntity = response.getEntity();
Below is the original snippet of code with deprecated HttpClient 4.0 API:
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(url);
FileBody bin = new FileBody(new File(fileName));
StringBody comment = new StringBody("Filename: " + fileName);
MultipartEntity reqEntity = new MultipartEntity();
reqEntity.addPart("bin", bin);
reqEntity.addPart("comment", comment);
httppost.setEntity(reqEntity);
HttpResponse response = httpclient.execute(httppost);
HttpEntity resEntity = response.getEntity();
These are the Maven dependencies I have.
Java Code:
HttpClient httpclient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
FileBody uploadFilePart = new FileBody(uploadFile);
MultipartEntity reqEntity = new MultipartEntity();
reqEntity.addPart("upload-file", uploadFilePart);
httpPost.setEntity(reqEntity);
HttpResponse response = httpclient.execute(httpPost);
Maven Dependencies in pom.xml:
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.0.1</version>
<scope>compile</scope>
</dependency>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpmime</artifactId>
<version>4.0.1</version>
<scope>compile</scope>
</dependency>
If size of the JARs matters (e.g. in case of applet), one can also directly use httpmime with java.net.HttpURLConnection instead of HttpClient.
httpclient-4.2.4: 423KB
httpmime-4.2.4: 26KB
httpcore-4.2.4: 222KB
commons-codec-1.6: 228KB
commons-logging-1.1.1: 60KB
Sum: 959KB
httpmime-4.2.4: 26KB
httpcore-4.2.4: 222KB
Sum: 248KB
Code:
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setDoOutput(true);
connection.setRequestMethod("POST");
FileBody fileBody = new FileBody(new File(fileName));
MultipartEntity multipartEntity = new MultipartEntity(HttpMultipartMode.STRICT);
multipartEntity.addPart("file", fileBody);
connection.setRequestProperty("Content-Type", multipartEntity.getContentType().getValue());
OutputStream out = connection.getOutputStream();
try {
multipartEntity.writeTo(out);
} finally {
out.close();
}
int status = connection.getResponseCode();
...
Dependency in pom.xml:
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpmime</artifactId>
<version>4.2.4</version>
</dependency>
Use this code to upload images or any other files to the server using post in multipart.
import java.io.File;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.mime.MultipartEntity;
import org.apache.http.entity.mime.content.FileBody;
import org.apache.http.entity.mime.content.StringBody;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.impl.client.DefaultHttpClient;
public class SimplePostRequestTest {
public static void main(String[] args) throws UnsupportedEncodingException, IOException {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://192.168.0.102/uploadtest/upload_photo");
try {
FileBody bin = new FileBody(new File("/home/ubuntu/cd.png"));
StringBody id = new StringBody("3");
MultipartEntity reqEntity = new MultipartEntity();
reqEntity.addPart("upload_image", bin);
reqEntity.addPart("id", id);
reqEntity.addPart("image_title", new StringBody("CoolPic"));
httppost.setEntity(reqEntity);
System.out.println("Requesting : " + httppost.getRequestLine());
ResponseHandler<String> responseHandler = new BasicResponseHandler();
String responseBody = httpclient.execute(httppost, responseHandler);
System.out.println("responseBody : " + responseBody);
} catch (ClientProtocolException e) {
} finally {
httpclient.getConnectionManager().shutdown();
}
}
}
it requires below files to upload.
libraries are
httpclient-4.1.2.jar,
httpcore-4.1.2.jar,
httpmime-4.1.2.jar,
httpclient-cache-4.1.2.jar,
commons-codec.jar
and
commons-logging-1.1.1.jar
to be in classpath.
Here's a solution that does not require any libraries.
This routine transmits every file in the directory d:/data/mpf10
to urlToConnect
String boundary = Long.toHexString(System.currentTimeMillis());
URLConnection connection = new URL(urlToConnect).openConnection();
connection.setDoOutput(true);
connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
PrintWriter writer = null;
try {
writer = new PrintWriter(new OutputStreamWriter(connection.getOutputStream(), "UTF-8"));
File dir = new File("d:/data/mpf10");
for (File file : dir.listFiles()) {
if (file.isDirectory()) {
continue;
}
writer.println("--" + boundary);
writer.println("Content-Disposition: form-data; name=\"" + file.getName() + "\"; filename=\"" + file.getName() + "\"");
writer.println("Content-Type: text/plain; charset=UTF-8");
writer.println();
BufferedReader reader = null;
try {
reader = new BufferedReader(new InputStreamReader(new FileInputStream(file), "UTF-8"));
for (String line; (line = reader.readLine()) != null;) {
writer.println(line);
}
} finally {
if (reader != null) {
reader.close();
}
}
}
writer.println("--" + boundary + "--");
} finally {
if (writer != null) writer.close();
}
// Connection is lazily executed whenever you request any status.
int responseCode = ((HttpURLConnection) connection).getResponseCode();
// Handle response
You can also use REST Assured which builds on HTTP Client. It's very simple:
given().multiPart(new File("/somedir/file.bin")).when().post("/fileUpload");
httpcomponents-client-4.0.1
worked for me. However, I had to add the external jar apache-mime4j-0.6.jar
(org.apache.james.mime4j) otherwise
reqEntity.addPart("bin", bin);
would not compile. Now it's working like charm.
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