How to use

getHeaderField

method

in

java.net.URLConnection

 HttpURLConnection con = (HttpURLConnection)(new URL( url ).openConnection());
con.setInstanceFollowRedirects( false );
con.connect();
int responseCode = con.getResponseCode();
System.out.println( responseCode );
String location = con.getHeaderField( "Location" );
System.out.println( location );

 URL url = new URL(url);
HttpURLConnection ucon = (HttpURLConnection) url.openConnection();
ucon.setInstanceFollowRedirects(false);
URL secondURL = new URL(ucon.getHeaderField("Location"));
URLConnection conn = secondURL.openConnection();

@JsonCreator
public HttpFirehoseFactory(
  @JsonProperty("uris") List<URI> uris,
  @JsonProperty("maxCacheCapacityBytes") Long maxCacheCapacityBytes,
  @JsonProperty("maxFetchCapacityBytes") Long maxFetchCapacityBytes,
  @JsonProperty("prefetchTriggerBytes") Long prefetchTriggerBytes,
  @JsonProperty("fetchTimeout") Long fetchTimeout,
  @JsonProperty("maxFetchRetry") Integer maxFetchRetry
) throws IOException
{
 super(maxCacheCapacityBytes, maxFetchCapacityBytes, prefetchTriggerBytes, fetchTimeout, maxFetchRetry);
 this.uris = uris;
 Preconditions.checkArgument(uris.size() > 0, "Empty URIs");
 final URLConnection connection = uris.get(0).toURL().openConnection();
 final String acceptRanges = connection.getHeaderField(HttpHeaders.ACCEPT_RANGES);
 this.supportContentRange = acceptRanges != null && "bytes".equalsIgnoreCase(acceptRanges);
}

 URL url = new URL("JSPURL");
URLConnection conn = url.openConnection();
for (int i = 0;; i++) {
 String headerName = conn.getHeaderFieldKey(i);
 String headerValue = conn.getHeaderField(i);
 System.out.println(headerName + "===");
 System.out.println(headerValue);
 if (headerName == null && headerValue == null) {
  break;
 }
}

 HttpURLConnection conn = (HttpURLConnection) feedUrl.openConnection();
int responseCode = conn.getResponseCode();
if( responseCode == 307 ){
  String location = conn.getHeaderField("location");
  feedUrl = new URL(location);
  conn = (HttpURLConnection) this.feedUrl.openConnection();
}

private static String handleRedirect(URLConnection con, String url) throws IOException {
  if (!(con instanceof HttpURLConnection)) return url;
  if (!isRedirect(((HttpURLConnection)con).getResponseCode())) return url;
  return con.getHeaderField("Location");
}

/**
 * If the server advertises CLI endpoint, returns its location.
 * @deprecated Specific to {@link Mode#REMOTING}.
 */
@Deprecated
protected CliPort getCliTcpPort(URL url) throws IOException {
  if (url.getHost()==null || url.getHost().length()==0) {
    throw new IOException("Invalid URL: "+url);
  }
  URLConnection head = url.openConnection();
  try {
    head.connect();
  } catch (IOException e) {
    throw (IOException)new IOException("Failed to connect to "+url).initCause(e);
  }
  String h = head.getHeaderField("X-Jenkins-CLI-Host");
  if (h==null)    h = head.getURL().getHost();
  String p1 = head.getHeaderField("X-Jenkins-CLI-Port");
  if (p1==null)    p1 = head.getHeaderField("X-Hudson-CLI-Port");   // backward compatibility
  String p2 = head.getHeaderField("X-Jenkins-CLI2-Port");
  String identity = head.getHeaderField("X-Instance-Identity");
  flushURLConnection(head);
  if (p1==null && p2==null) {
    verifyJenkinsConnection(head);
    throw new IOException("No X-Jenkins-CLI2-Port among " + head.getHeaderFields().keySet());
  }
  if (p2!=null)   return new CliPort(new InetSocketAddress(h,Integer.parseInt(p2)),identity,2);
  else            return new CliPort(new InetSocketAddress(h,Integer.parseInt(p1)),identity,1);
}

 public void checkURL(URL url) throws IOException {
  HttpURLConnection conn = (HttpURLConnection) url.openConnection();
  conn.setRequestMethod("GET");
  System.out.println(String.format("Fetching %s ...", url));
  try {
    int responseCode = conn.getResponseCode();
    if (responseCode == 200) {
      System.out.println(String.format("Site is up, content length = %s", conn.getHeaderField("content-length")));
    } else {
      System.out.println(String.format("Site is up, but returns non-ok status = %d", responseCode));
    }
  } catch (java.net.UnknownHostException e) {
    System.out.println("Site is down");
  }
}

URL resourceUrl, base, next;
HttpURLConnection conn;
String location;
...
while (true)
{
  resourceUrl = new URL(url);
  conn        = (HttpURLConnection) resourceUrl.openConnection();
  conn.setConnectTimeout(15000);
  conn.setReadTimeout(15000);
  conn.setInstanceFollowRedirects(false);   // Make the logic below easier to detect redirections
  conn.setRequestProperty("User-Agent", "Mozilla/5.0...");
  switch (conn.getResponseCode())
  {
   case HttpURLConnection.HTTP_MOVED_PERM:
   case HttpURLConnection.HTTP_MOVED_TEMP:
     location = conn.getHeaderField("Location");
     base     = new URL(url);               
     next     = new URL(base, location);  // Deal with relative URLs
     url      = next.toExternalForm();
     continue;
  }
  break;
}
is = conn.openStream();
...

 URLConnection connection = new URL("http://foo.bar/w23afv").openConnection();
String contentType = connection.getHeaderField("Content-Type");
boolean image = contentType.startsWith("image/");

private static String extractResponseString(URLConnection connection) throws IOException {
  /* Handle input. */
  HttpURLConnection http = (HttpURLConnection) connection;
  int status = http.getResponseCode();
  String charset = getCharset(connection.getHeaderField("Content-Type"));
  if (status == 200) {
    return readResponseBody(http, charset);
  } else {
    return readErrorResponseBody(http, status, charset);
  }
}

public void display(URL url) {
 try {
   URLConnection urlc = url.openConnection();
   String contentType = urlc.getHeaderField("Content-Type");
   byte[] ba = Files.forIO().readFrom(urlc.getInputStream());
   display(new String(ba, determinCharset(contentType, "utf-8")));
 } catch (Exception e) {
   throw new RuntimeException("Error when accessing URL: " + url, e);
 }
}

 HttpURLConnection con = (HttpURLConnection) (new URL(url).openConnection());
con.setInstanceFollowRedirects(false);
con.connect();
int responseCode = con.getResponseCode();
System.out.println(responseCode);
String location = con.getHeaderField("Location");
System.out.println(location);

@SuppressFBWarnings(value = "RCN_REDUNDANT_NULLCHECK_OF_NULL_VALUE", justification = "Due to whatever reason FindBugs reports it fot try-with-resources")
static int sshConnection(String jenkinsUrl, String user, List<String> args, PrivateKeyProvider provider, final boolean strictHostKey) throws IOException {
  Logger.getLogger(SecurityUtils.class.getName()).setLevel(Level.WARNING); // suppress: BouncyCastle not registered, using the default JCE provider
  URL url = new URL(jenkinsUrl + "login");
  URLConnection conn = url.openConnection();
  CLI.verifyJenkinsConnection(conn);
  String endpointDescription = conn.getHeaderField("X-SSH-Endpoint");

private static Response extractResponseObject(URLConnection connection) throws IOException {
  /* Handle input. */
  HttpURLConnection http = (HttpURLConnection) connection;
  int status = http.getResponseCode();
  String charset = getCharset(connection.getHeaderField("Content-Type"));
  String body;
  if (status == 200) {
    body = readResponseBody(http, charset);
  } else {
    body = readErrorResponseBodyDoNotDie(http, status, charset);
  }
  return Response.response(status, http.getHeaderFields(), http.getResponseMessage(), body);
}

URL url = new URL("https://android.clients.google.com/c2dm/send");
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setDoOutput(true);
conn.setUseCaches(false);
out.close();
int responseCode = conn.getResponseCode();
String updatedAuthToken = conn.getHeaderField(UPDATE_CLIENT_AUTH);
if (updatedAuthToken != null && !auth_key.equals(updatedAuthToken)) {
  Log.i("C2DM",

 final URL uri=new URL(...);
URLConnection ucon;
try
 {
 ucon=uri.openConnection();
 ucon.connect();
 final String contentLengthStr=ucon.getHeaderField("content-length");
 //...
 }
catch(final IOException e1)
 {
 }

private static byte[] extractResponseBytes(URLConnection connection) throws IOException {
  /* Handle input. */
  HttpURLConnection http = (HttpURLConnection) connection;
  int status = http.getResponseCode();
  //System.out.println("CONTENT-TYPE" + connection.getHeaderField("Content-TypeT"));
  if (status == 200) {
    return readResponseBodyAsBytes(http);
  } else {
    String charset = getCharset(connection.getHeaderField("Content-Type"));
    readErrorResponseBody(http, status, charset);
    return null;
  }
}

  URL url = new URL(AUTH_URL);
  HttpURLConnection urlConnection = (HttpURLConnection) url.openConnection();
  urlConnection.setRequestMethod("POST");
  urlConnection.setDoOutput(true);
  outStreamWriter.close();
  int responseCode = urlConnection.getResponseCode();
FileInputStream fileStream = new FileInputStream(file);
int responseCode = urlConnection.getResponseCode();
    Log.d(TAG, String.format("Headers keys %s.", keys));
    for (String key : keySet) {
      Log.d(TAG, String.format("Header key %s value %s.", key, urlConnection.getHeaderField(key)));          
    URL url = new URL(uploadUrl);
    outStreamWriter.close();
    int responseCode = connection.getResponseCode();
    return connection.getHeaderField("Location");

try {
  fl = new File(System.getProperty("user.home").replace("\\", "/") + "/Desktop/Screenshots.zip");
  dl = new URL("http://ds-forums.com/kyle-tests/uploads/Screenshots.zip");
  os = new FileOutputStream(fl);
  is = dl.openStream();
  dl.openConnection().getHeaderField("Content-Length");