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copied!<p>You'd normally use <a href="http://java.sun.com/javase/6/docs/api/java/net/URLConnection.html" rel="noreferrer"><code>java.net.URLConnection</code></a> to fire HTTP requests. You'd also normally use <a href="http://www.w3.org/TR/html401/interact/forms.html#h-17.13.4.2" rel="noreferrer"><code>multipart/form-data</code></a> encoding for mixed POST content (binary and character data). Click the link, it contains information and an example how to compose a <code>multipart/form-data</code> request body. The specification is in more detail described in <a href="http://www.faqs.org/rfcs/rfc2388.html" rel="noreferrer">RFC2388</a>.</p> <p>Here's a kickoff example:</p> <pre><code>String url = "http://example.com/upload"; String charset = "UTF-8"; String param = "value"; File textFile = new File("/path/to/file.txt"); File binaryFile = new File("/path/to/file.bin"); String boundary = Long.toHexString(System.currentTimeMillis()); // Just generate some unique random value. String CRLF = "\r\n"; // Line separator required by multipart/form-data. URLConnection connection = new URL(url).openConnection(); connection.setDoOutput(true); connection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary); try ( OutputStream output = connection.getOutputStream(); PrintWriter writer = new PrintWriter(new OutputStreamWriter(output, charset), true); ) { // Send normal param. writer.append("--" + boundary).append(CRLF); writer.append("Content-Disposition: form-data; name=\"param\"").append(CRLF); writer.append("Content-Type: text/plain; charset=" + charset).append(CRLF); writer.append(CRLF).append(param).append(CRLF).flush(); // Send text file. writer.append("--" + boundary).append(CRLF); writer.append("Content-Disposition: form-data; name=\"textFile\"; filename=\"" + textFile.getName() + "\"").append(CRLF); writer.append("Content-Type: text/plain; charset=" + charset).append(CRLF); // Text file itself must be saved in this charset! writer.append(CRLF).flush(); Files.copy(textFile.toPath(), output); output.flush(); // Important before continuing with writer! writer.append(CRLF).flush(); // CRLF is important! It indicates end of boundary. // Send binary file. writer.append("--" + boundary).append(CRLF); writer.append("Content-Disposition: form-data; name=\"binaryFile\"; filename=\"" + binaryFile.getName() + "\"").append(CRLF); writer.append("Content-Type: " + URLConnection.guessContentTypeFromName(binaryFile.getName())).append(CRLF); writer.append("Content-Transfer-Encoding: binary").append(CRLF); writer.append(CRLF).flush(); Files.copy(binaryFile.toPath(), output); output.flush(); // Important before continuing with writer! writer.append(CRLF).flush(); // CRLF is important! It indicates end of boundary. // End of multipart/form-data. writer.append("--" + boundary + "--").append(CRLF).flush(); } // Request is lazily fired whenever you need to obtain information about response. int responseCode = ((HttpURLConnection) connection).getResponseCode(); System.out.println(responseCode); // Should be 200 </code></pre> <p>This code is less verbose when you use a 3rd party library like Apache Commons <a href="http://hc.apache.org/" rel="noreferrer">HttpComponents Client</a>.</p> <p>The Apache Commons <a href="http://commons.apache.org/fileupload" rel="noreferrer">FileUpload</a> as some incorrectly suggest here is only of interest in the <strong>server side</strong>. You can't use and don't need it at the client side.</p> <h3>See also</h3> <ul> <li><a href="https://stackoverflow.com/questions/2793150/using-java-net-urlconnection-to-fire-and-handle-http-requests">Using java.net.URLConnection to fire and handle HTTP requests</a></li> </ul>

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