Here is example code which can upload files to any server without using any third party library in java
import java.io.BufferedReader;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLEncoder;
import java.util.Map;
import com.linkwithweb.callback.ResponseHandler;
/**
* @author kumara
*
*/
public class HttpPost {
URL u;
private static CookieManager cm = new CookieManager();
/**
* @param args
*/
public static void main(String args[]) {
// post();
new HttpPost().sendFile("http://localhost:8080/Server/LoginServlet",
"serverxml/login.xml");
}
/**
*
*/
private void post() {
String s = URLEncoder.encode("A Test string to send to a servlet");
try {
HttpPost post = new HttpPost();
post.u = new URL("http://myhost/servlet");
// Open the connection and prepare to POST
URLConnection uc = u.openConnection();
uc.setDoOutput(true);
uc.setDoInput(true);
uc.setAllowUserInteraction(false);
DataOutputStream dstream = new DataOutputStream(
uc.getOutputStream());
// The POST line
dstream.writeBytes(s);
dstream.close();
// Read Response
InputStream in = uc.getInputStream();
int x;
while ((x = in.read()) != -1) {
System.out.write(x);
}
in.close();
BufferedReader r = new BufferedReader(new InputStreamReader(in));
StringBuffer buf = new StringBuffer();
String line;
while ((line = r.readLine()) != null) {
buf.append(line);
}
} catch (IOException e) {
e.printStackTrace(); // should do real exception handling
}
}
/**
* @param url
* Url to send data to
* @param file1
* path to local file to upload
* @return int if 0 then all ok else see value and look in code!
*/
public int sendFile(String surl, String file1) {
int rtn = 1;
HttpURLConnection conn = null;
BufferedReader br = null;
DataOutputStream dos = null;
DataInputStream inStream = null;
InputStream is = null;
OutputStream os = null;
boolean ret = false;
String StrMessage = "";
String exsistingFileName = file1;
File fFile2Snd = new File(exsistingFileName);
String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "***232404jkg4220957934FW**";
int bytesRead, bytesAvailable, bufferSize;
byte[] buffer;
int maxBufferSize = 1 * 1024 * 1024;
String responseFromServer = "";
String urlString = surl;// "http://localhost:81/FileUpload/requestupload";
// urlString =
// "http://a.com/sel2in/prjs/php/p12/skewmypic/v1/getBytes.php";
try {
// ------------------ CLIENT REQUEST
FileInputStream fileInputStream = new FileInputStream(new File(
exsistingFileName));
rtn++;
// open a URL connection to the Servlet
URL url = new URL(urlString);
rtn++;
// Open a HTTP connection to the URL
conn = (HttpURLConnection) url.openConnection();
// Allow Inputs
conn.setDoInput(true);
// Allow Outputs
conn.setDoOutput(true);
// Don't use a cached copy.
conn.setUseCaches(false);
// Use a post method.
conn.setRequestMethod("POST");
conn.setRequestProperty("Connection", "Keep-Alive");
conn.setRequestProperty("Content-Type",
"multipart/form-data;boundary=" + boundary);
dos = new DataOutputStream(conn.getOutputStream());
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes("Content-Disposition: form-data; name=\"userfile\";"
+ " filename=\"" + fFile2Snd.getName() + "\"" + lineEnd);
dos.writeBytes(lineEnd);
rtn++;
// create a buffer of maximum size
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
buffer = new byte[bufferSize];
// read file and write it into form...
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
while (bytesRead > 0) {
dos.write(buffer, 0, bufferSize);
bytesAvailable = fileInputStream.available();
bufferSize = Math.min(bytesAvailable, maxBufferSize);
bytesRead = fileInputStream.read(buffer, 0, bufferSize);
}
// send multipart form data necesssary after file data...
dos.writeBytes(lineEnd);
dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
// close streams
fileInputStream.close();
dos.flush();
dos.close();
} catch (MalformedURLException ex) {
System.out.println("From ServletCom2 CLIENT REQUEST:" + ex);
}
catch (IOException ioe) {
System.out.println("From ServletCom2 CLIENT REQUEST:" + ioe);
}
// ------------------ read the SERVER RESPONSE
try {
System.out.println("Server response is: \n");
inStream = new DataInputStream(conn.getInputStream());
String str;
while ((str = inStream.readLine()) != null) {
System.out.println(str);
System.out.println("");
}
inStream.close();
System.out.println("\nEND Server response ");
} catch (IOException ioex) {
System.out.println("From (ServerResponse): " + ioex);
}
rtn = 0;
return rtn;
}
/**
* @param fileContent
* content of file
* @param contextParams
* TODO
* @param url
* Url to send data to
* @return int if 0 then all ok else see value and look in code!
*/
public int uploadStringAsFile(String surl, String fileContent,
String requestIdentifier, ResponseHandler responseHandler,
Map contextParams) {
fileContent = fileContent.trim();
int rtn = 1;
HttpURLConnection conn = null;
BufferedReader br = null;
DataOutputStream dos = null;
DataInputStream inStream = null;
InputStream is = null;
OutputStream os = null;
boolean ret = false;
String StrMessage = "";
String lineEnd = "\r\n";
String twoHyphens = "--";
String boundary = "***232404jkg4220957934FW**";
int bytesRead, bytesAvailable, bufferSize;
byte[] buffer;
int maxBufferSize = 1 * 1024 * 1024;
String responseFromServer = "";
String urlString = surl;// "http://localhost:81/FileUpload/requestupload";
// urlString =
// "http://a.com/sel2in/prjs/php/p12/skewmypic/v1/getBytes.php";
try {
// ------------------ CLIENT REQUEST
rtn++;
// open a URL connection to the Servlet
URL url = new URL(urlString);
rtn++;
// Open a HTTP connection to the URL
conn = (HttpURLConnection) url.openConnection();
cm.setCookies(conn);
// Allow Inputs
conn.setDoInput(true);
// Allow Outputs
conn.setDoOutput(true);
// Don't use a cached copy.
conn.setUseCaches(false);
// Use a post method.
conn.setRequestMethod("POST");
conn.setRequestProperty("Connection", "Keep-Alive");
conn.setRequestProperty("Content-Type",
"multipart/form-data;boundary=" + boundary);
dos = new DataOutputStream(conn.getOutputStream());
dos.writeBytes(twoHyphens + boundary + lineEnd);
dos.writeBytes("Content-Disposition: form-data; name=\"userfile\";"
+ " filename=\"file\"" + lineEnd);
dos.writeBytes(lineEnd);
rtn++;
// create a buffer of maximum size
bytesAvailable = fileContent.getBytes("UTF-8").length;
bufferSize = Math.min(bytesAvailable, maxBufferSize);
buffer = new byte[bufferSize];
// read file and write it into form...
dos.write(fileContent.getBytes("UTF-8"), 0, bufferSize);
// send multipart form data necesssary after file data...
dos.writeBytes(lineEnd);
dos.writeBytes(twoHyphens + boundary + twoHyphens + lineEnd);
// close streams
dos.flush();
dos.close();
} catch (MalformedURLException ex) {
System.out.println("From ServletCom2 CLIENT REQUEST:" + ex);
}
catch (IOException ioe) {
System.out.println("From ServletCom2 CLIENT REQUEST:" + ioe);
}
// ------------------ read the SERVER RESPONSE
StringBuffer returnString = new StringBuffer();
try {
// System.out.println("Server response is: \n");
cm.storeCookies(conn);
inStream = new DataInputStream(conn.getInputStream());
String str;
while ((str = inStream.readLine()) != null) {
returnString.append(str + "\r\n");
}
inStream.close();
// System.out.println("\nEND Server response ");
} catch (IOException ioex) {
System.out.println("From (ServerResponse): " + ioex);
} finally {
if (responseHandler != null) {
responseHandler.hadleResponse(requestIdentifier,
returnString.toString(), contextParams);
}
}
rtn = 0;
return rtn;
}
/**
* @param urlString
*/
public void storeAndGetCookies(String urlString) {
CookieManager cm = new CookieManager();
try {
URL url = new URL(urlString);
URLConnection conn = url.openConnection();
conn.connect();
cm.storeCookies(conn);
System.out.println(cm);
cm.setCookies(url.openConnection());
} catch (IOException ioe) {
ioe.printStackTrace();
}
}
}
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