File	Doc	Category	Size	Date	Package
HttpURLConnection.java	API Doc	Java SE 6 API	21180	Tue Jun 10 00:25:40 BST 2008	java.net

HttpURLConnection

• java.lang.Object
  • java.net.URLConnection

Fields Summary
protected String	method The HTTP method (GET,POST,PUT,etc.).
protected int	chunkLength The chunk-length when using chunked encoding streaming mode for output. A value of -1 means chunked encoding is disabled for output.
protected int	fixedContentLength The fixed content-length when using fixed-length streaming mode. A value of -1 means fixed-length streaming mode is disabled for output.
private static final int	DEFAULT_CHUNK_SIZE
protected int	responseCode An int representing the three digit HTTP Status-Code. 1xx: Informational 2xx: Success 3xx: Redirection 4xx: Client Error 5xx: Server Error
protected String	responseMessage The HTTP response message.
private static boolean	followRedirects
protected boolean	instanceFollowRedirects If true, the protocol will automatically follow redirects. If false, the protocol will not automatically follow redirects. This field is set by the setInstanceFollowRedirects method. Its value is returned by the getInstanceFollowRedirects method. Its default value is based on the value of the static followRedirects at HttpURLConnection construction time.
private static final String[]	methods
public static final int	HTTP_OK HTTP Status-Code 200: OK.
public static final int	HTTP_CREATED HTTP Status-Code 201: Created.
public static final int	HTTP_ACCEPTED HTTP Status-Code 202: Accepted.
public static final int	HTTP_NOT_AUTHORITATIVE HTTP Status-Code 203: Non-Authoritative Information.
public static final int	HTTP_NO_CONTENT HTTP Status-Code 204: No Content.
public static final int	HTTP_RESET HTTP Status-Code 205: Reset Content.
public static final int	HTTP_PARTIAL HTTP Status-Code 206: Partial Content.
public static final int	HTTP_MULT_CHOICE HTTP Status-Code 300: Multiple Choices.
public static final int	HTTP_MOVED_PERM HTTP Status-Code 301: Moved Permanently.
public static final int	HTTP_MOVED_TEMP HTTP Status-Code 302: Temporary Redirect.
public static final int	HTTP_SEE_OTHER HTTP Status-Code 303: See Other.
public static final int	HTTP_NOT_MODIFIED HTTP Status-Code 304: Not Modified.
public static final int	HTTP_USE_PROXY HTTP Status-Code 305: Use Proxy.
public static final int	HTTP_BAD_REQUEST HTTP Status-Code 400: Bad Request.
public static final int	HTTP_UNAUTHORIZED HTTP Status-Code 401: Unauthorized.
public static final int	HTTP_PAYMENT_REQUIRED HTTP Status-Code 402: Payment Required.
public static final int	HTTP_FORBIDDEN HTTP Status-Code 403: Forbidden.
public static final int	HTTP_NOT_FOUND HTTP Status-Code 404: Not Found.
public static final int	HTTP_BAD_METHOD HTTP Status-Code 405: Method Not Allowed.
public static final int	HTTP_NOT_ACCEPTABLE HTTP Status-Code 406: Not Acceptable.
public static final int	HTTP_PROXY_AUTH HTTP Status-Code 407: Proxy Authentication Required.
public static final int	HTTP_CLIENT_TIMEOUT HTTP Status-Code 408: Request Time-Out.
public static final int	HTTP_CONFLICT HTTP Status-Code 409: Conflict.
public static final int	HTTP_GONE HTTP Status-Code 410: Gone.
public static final int	HTTP_LENGTH_REQUIRED HTTP Status-Code 411: Length Required.
public static final int	HTTP_PRECON_FAILED HTTP Status-Code 412: Precondition Failed.
public static final int	HTTP_ENTITY_TOO_LARGE HTTP Status-Code 413: Request Entity Too Large.
public static final int	HTTP_REQ_TOO_LONG HTTP Status-Code 414: Request-URI Too Large.
public static final int	HTTP_UNSUPPORTED_TYPE HTTP Status-Code 415: Unsupported Media Type.
public static final int	HTTP_SERVER_ERROR HTTP Status-Code 500: Internal Server Error.
public static final int	HTTP_INTERNAL_ERROR HTTP Status-Code 500: Internal Server Error.
public static final int	HTTP_NOT_IMPLEMENTED HTTP Status-Code 501: Not Implemented.
public static final int	HTTP_BAD_GATEWAY HTTP Status-Code 502: Bad Gateway.
public static final int	HTTP_UNAVAILABLE HTTP Status-Code 503: Service Unavailable.
public static final int	HTTP_GATEWAY_TIMEOUT HTTP Status-Code 504: Gateway Timeout.
public static final int	HTTP_VERSION HTTP Status-Code 505: HTTP Version Not Supported.

Constructors Summary
protected HttpURLConnection(URL u) Constructor for the HttpURLConnection. param u the URL super(u);

Methods Summary
public abstract void	disconnect() Indicates that other requests to the server are unlikely in the near future. Calling disconnect() should not imply that this HttpURLConnection instance can be reused for other requests.
public java.io.InputStream	getErrorStream() Returns the error stream if the connection failed but the server sent useful data nonetheless. The typical example is when an HTTP server responds with a 404, which will cause a FileNotFoundException to be thrown in connect, but the server sent an HTML help page with suggestions as to what to do. This method will not cause a connection to be initiated. If the connection was not connected, or if the server did not have an error while connecting or if the server had an error but no error data was sent, this method will return null. This is the default. return an error stream if any, null if there have been no errors, the connection is not connected or the server sent no useful data. return null;
public static boolean	getFollowRedirects() Returns a boolean indicating whether or not HTTP redirects (3xx) should be automatically followed. return true if HTTP redirects should be automatically followed, false if not. see #setFollowRedirects(boolean) return followRedirects;
public java.lang.String	getHeaderField(int n) Returns the value for the nth header field. Some implementations may treat the 0th header field as special, i.e. as the status line returned by the HTTP server. This method can be used in conjunction with the {@link #getHeaderFieldKey getHeaderFieldKey} method to iterate through all the headers in the message. param n an index, where n>=0. return the value of the nth header field, or null if the value does not exist. see java.net.HttpURLConnection#getHeaderFieldKey(int) return null;
public long	getHeaderFieldDate(java.lang.String name, long Default) String dateString = getHeaderField(name); try { if (dateString.indexOf("GMT") == -1) { dateString = dateString+" GMT"; } return Date.parse(dateString); } catch (Exception e) { } return Default;
public java.lang.String	getHeaderFieldKey(int n) Returns the key for the nth header field. Some implementations may treat the 0th header field as special, i.e. as the status line returned by the HTTP server. In this case, {@link #getHeaderField(int) getHeaderField(0)} returns the status line, but getHeaderFieldKey(0) returns null. param n an index, where n >=0. return the key for the nth header field, or null if the key does not exist. return null;
public boolean	getInstanceFollowRedirects() Returns the value of this HttpURLConnection's instanceFollowRedirects field. return the value of this HttpURLConnection's instanceFollowRedirects field. see java.net.HttpURLConnection#instanceFollowRedirects see #setInstanceFollowRedirects(boolean) since 1.3 return instanceFollowRedirects;
public java.security.Permission	getPermission() int port = url.getPort(); port = port < 0 ? 80 : port; String host = url.getHost() + ":" + port; Permission permission = new SocketPermission(host, "connect"); return permission;
public java.lang.String	getRequestMethod() Get the request method. return the HTTP request method see #setRequestMethod(java.lang.String) return method;
public int	getResponseCode() Gets the status code from an HTTP response message. For example, in the case of the following status lines: HTTP/1.0 200 OK HTTP/1.0 401 Unauthorized It will return 200 and 401 respectively. Returns -1 if no code can be discerned from the response (i.e., the response is not valid HTTP). throws IOException if an error occurred connecting to the server. return the HTTP Status-Code, or -1 /* * We're got the response code already */ if (responseCode != -1) { return responseCode; } /* * Ensure that we have connected to the server. Record * exception as we need to re-throw it if there isn't * a status line. */ Exception exc = null; try { getInputStream(); } catch (Exception e) { exc = e; } /* * If we can't a status-line then re-throw any exception * that getInputStream threw. */ String statusLine = getHeaderField(0); if (statusLine == null) { if (exc != null) { if (exc instanceof RuntimeException) throw (RuntimeException)exc; else throw (IOException)exc; } return -1; } /* * Examine the status-line - should be formatted as per * section 6.1 of RFC 2616 :- * * Status-Line = HTTP-Version SP Status-Code SP Reason-Phrase * * If status line can't be parsed return -1. */ if (statusLine.startsWith("HTTP/1.")) { int codePos = statusLine.indexOf(' "); if (codePos > 0) { int phrasePos = statusLine.indexOf(' ", codePos+1); if (phrasePos > 0 && phrasePos < statusLine.length()) { responseMessage = statusLine.substring(phrasePos+1); } // deviation from RFC 2616 - don't reject status line // if SP Reason-Phrase is not included. if (phrasePos < 0) phrasePos = statusLine.length(); try { responseCode = Integer.parseInt (statusLine.substring(codePos+1, phrasePos)); return responseCode; } catch (NumberFormatException e) { } } } return -1;
public java.lang.String	getResponseMessage() Gets the HTTP response message, if any, returned along with the response code from a server. From responses like: HTTP/1.0 200 OK HTTP/1.0 404 Not Found Extracts the Strings "OK" and "Not Found" respectively. Returns null if none could be discerned from the responses (the result was not valid HTTP). throws IOException if an error occurred connecting to the server. return the HTTP response message, or null getResponseCode(); return responseMessage;
public void	setChunkedStreamingMode(int chunklen) This method is used to enable streaming of a HTTP request body without internal buffering, when the content length is not known in advance. In this mode, chunked transfer encoding is used to send the request body. Note, not all HTTP servers support this mode. When output streaming is enabled, authentication and redirection cannot be handled automatically. A HttpRetryException will be thrown when reading the response if authentication or redirection are required. This exception can be queried for the details of the error. This method must be called before the URLConnection is connected. param chunklen The number of bytes to write in each chunk. If chunklen is less than or equal to zero, a default value will be used. throws IllegalStateException if URLConnection is already connected or if a different streaming mode is already enabled. see #setFixedLengthStreamingMode(int) since 1.5 if (connected) { throw new IllegalStateException ("Can't set streaming mode: already connected"); } if (fixedContentLength != -1) { throw new IllegalStateException ("Fixed length streaming mode set"); } chunkLength = chunklen <=0? DEFAULT_CHUNK_SIZE : chunklen;
public void	setFixedLengthStreamingMode(int contentLength) This method is used to enable streaming of a HTTP request body without internal buffering, when the content length is known in advance. An exception will be thrown if the application attempts to write more data than the indicated content-length, or if the application closes the OutputStream before writing the indicated amount. When output streaming is enabled, authentication and redirection cannot be handled automatically. A HttpRetryException will be thrown when reading the response if authentication or redirection are required. This exception can be queried for the details of the error. This method must be called before the URLConnection is connected. param contentLength The number of bytes which will be written to the OutputStream. throws IllegalStateException if URLConnection is already connected or if a different streaming mode is already enabled. throws IllegalArgumentException if a content length less than zero is specified. see #setChunkedStreamingMode(int) since 1.5 if (connected) { throw new IllegalStateException ("Already connected"); } if (chunkLength != -1) { throw new IllegalStateException ("Chunked encoding streaming mode set"); } if (contentLength < 0) { throw new IllegalArgumentException ("invalid content length"); } fixedContentLength = contentLength;
public static void	setFollowRedirects(boolean set) Sets whether HTTP redirects (requests with response code 3xx) should be automatically followed by this class. True by default. Applets cannot change this variable. If there is a security manager, this method first calls the security manager's checkSetFactory method to ensure the operation is allowed. This could result in a SecurityException. param set a boolean indicating whether or not to follow HTTP redirects. exception SecurityException if a security manager exists and its checkSetFactory method doesn't allow the operation. see SecurityManager#checkSetFactory see #getFollowRedirects() SecurityManager sec = System.getSecurityManager(); if (sec != null) { // seems to be the best check here... sec.checkSetFactory(); } followRedirects = set;
public void	setInstanceFollowRedirects(boolean followRedirects) Sets whether HTTP redirects (requests with response code 3xx) should be automatically followed by this HttpURLConnection instance. The default value comes from followRedirects, which defaults to true. param followRedirects a boolean indicating whether or not to follow HTTP redirects. see java.net.HttpURLConnection#instanceFollowRedirects see #getInstanceFollowRedirects since 1.3 instanceFollowRedirects = followRedirects;
public void	setRequestMethod(java.lang.String method) Set the method for the URL request, one of: GET POST HEAD OPTIONS PUT DELETE TRACE are legal, subject to protocol restrictions. The default method is GET. param method the HTTP method exception ProtocolException if the method cannot be reset or if the requested method isn't valid for HTTP. see #getRequestMethod() if (connected) { throw new ProtocolException("Can't reset method: already connected"); } // This restriction will prevent people from using this class to // experiment w/ new HTTP methods using java. But it should // be placed for security - the request String could be // arbitrarily long. for (int i = 0; i < methods.length; i++) { if (methods[i].equals(method)) { this.method = method; return; } } throw new ProtocolException("Invalid HTTP method: " + method);
public abstract boolean	usingProxy() Indicates if the connection is going through a proxy. return a boolean indicating if the connection is using a proxy.