Java HttpClient with PHP File Upload
In this article, we explore how to utilize the Java HttpClient library version 4.0 beta2 to upload a file to an Apache server running PHP.
Scenario and Issue
A developer aims to transfer a file from Java to PHP via the Jakarta HttpClient library. However, upon executing the request, the PHP server doesn't detect the uploaded file. The is_uploaded_file() function returns false, and the $_FILES variable remains empty.
Solution
To rectify this, we need to revise the Java code. The problem stems from the incorrect usage of the FileEntity. Here's the corrected code:
import java.io.File; import org.apache.http.HttpEntity; import org.apache.http.HttpResponse; import org.apache.http.HttpVersion; import org.apache.http.client.HttpClient; import org.apache.http.client.methods.HttpPost; import org.apache.http.entity.mime.MultipartEntity; import org.apache.http.entity.mime.content.ContentBody; import org.apache.http.entity.mime.content.FileBody; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.params.CoreProtocolPNames; import org.apache.http.util.EntityUtils; public class PostFile { public static void main(String[] args) throws Exception { HttpClient httpclient = new DefaultHttpClient(); httpclient.getParams().setParameter(CoreProtocolPNames.PROTOCOL_VERSION, HttpVersion.HTTP_1_1); HttpPost httppost = new HttpPost("http://localhost:9001/upload.php"); File file = new File("c:/TRASH/zaba_1.jpg"); MultipartEntity mpEntity = new MultipartEntity(); ContentBody cbFile = new FileBody(file, "image/jpeg"); mpEntity.addPart("userfile", cbFile); httppost.setEntity(mpEntity); System.out.println("executing request " + httppost.getRequestLine()); HttpResponse response = httpclient.execute(httppost); HttpEntity resEntity = response.getEntity(); System.out.println(response.getStatusLine()); if (resEntity != null) { System.out.println(EntityUtils.toString(resEntity)); } if (resEntity != null) { resEntity.consumeContent(); } httpclient.getConnectionManager().shutdown(); } }
The key change is using MultipartEntity instead of FileEntity. This allows us to send the file as a multipart form-data request, which is the expected format for PHP file uploads.
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