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@PauloLuan
Created June 3, 2014 13:46
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MultipartHTTPUtility.java
import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.PrintWriter;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.ArrayList;
import java.util.List;
public class MultipartHTTPUtility {
private final String boundary;
private static final String LINE_FEED = "\r\n";
private HttpURLConnection httpConnection;
private String charset = "UTF-8";
private OutputStream outputStream;
private PrintWriter writer;
/**
* This constructor initializes a new HTTP POST request with content
* type is set to multipart/form-data
*
* @param requestURL
* @param charset
* @throws IOException
*/
public MultipartHTTPUtility(String requestURL) throws IOException {
// creates a unique boundary based on time stamp
boundary = "===" + System.currentTimeMillis() + "===";
URL url = new URL(requestURL);
httpConnection = (HttpURLConnection) url.openConnection();
httpConnection.setUseCaches(false);
httpConnection.setDoOutput(true); // indicates POST method
httpConnection.setDoInput(true);
httpConnection.setRequestMethod("POST");
httpConnection.setRequestProperty("Connection", "Keep-Alive");
httpConnection.setRequestProperty("Content-Type", "multipart/form-data; boundary=" + boundary);
httpConnection.setChunkedStreamingMode(1024);
outputStream = httpConnection.getOutputStream();
writer = new PrintWriter(new OutputStreamWriter(outputStream, charset), true);
}
/**
* Adds a form field to the request
*
* @param name
* field name
* @param value
* field value
*/
public void addFormField(String name, String value) {
writer.append("--" + boundary).append(LINE_FEED);
writer.append("Content-Disposition: form-data; name=\"" + name + "\"").append(LINE_FEED);
writer.append("Content-Type: text/plain; charset=" + charset).append(LINE_FEED);
writer.append(LINE_FEED);
writer.append(value).append(LINE_FEED);
writer.flush();
}
/**
* Adds a upload file section to the request
*
* @param fieldName
* name attribute in <input type="file" name="..." />
* @param uploadFile
* a File to be uploaded
* @throws IOException
*/
public void addFilePart(String fieldName, File uploadFile) throws IOException {
String fileName = uploadFile.getName();
writer.append("--" + boundary).append(LINE_FEED);
writer.append("Content-Disposition: form-data; name=\"" + fieldName + "\"; filename=\"" + fileName + "\"").append(LINE_FEED);
writer.append("Content-Type: " + URLConnection.guessContentTypeFromName(fileName)).append(LINE_FEED);
writer.append("Content-Transfer-Encoding: binary").append(LINE_FEED);
writer.append(LINE_FEED);
writer.flush();
FileInputStream inputStream = new FileInputStream(uploadFile);
byte[] buffer = new byte[4096];
int bytesRead = -1;
while ((bytesRead = inputStream.read(buffer)) != -1) {
outputStream.write(buffer, 0, bytesRead);
}
outputStream.flush();
inputStream.close();
writer.append(LINE_FEED);
writer.flush();
}
/**
* Adds a header field to the request.
*
* @param name
* - name of the header field
* @param value
* - value of the header field
*/
public void addHeaderField(String name, String value) {
writer.append(name + ": " + value).append(LINE_FEED);
writer.flush();
}
/**
* Completes the request and receives response from the server.
*
* @return a list of Strings as response in case the server returned
* status OK, otherwise an exception is thrown.
* @throws IOException
*/
public List<String> finish() throws IOException {
List<String> response = new ArrayList<String>();
writer.append(LINE_FEED).flush();
writer.append("--" + boundary + "--").append(LINE_FEED);
writer.close();
// checks server's status code first
int status = httpConnection.getResponseCode();
if (status == HttpURLConnection.HTTP_OK) {
BufferedReader reader = new BufferedReader(new InputStreamReader(httpConnection.getInputStream()));
String line = null;
while ((line = reader.readLine()) != null) {
response.add(line);
}
reader.close();
httpConnection.disconnect();
}
else {
throw new IOException("Server returned non-OK status: " + status);
}
return response;
}
}
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