java.lang.Objectjava.net.URLConnection
java.net.HttpURLConnection
public abstract class HttpURLConnection
A URLConnection with support for HTTP-specific features. See the spec for details.
Each HttpURLConnection instance is used to make a single request but the underlying network connection to the HTTP server may be transparently shared by other instances. Calling the close() methods on the InputStream or OutputStream of an HttpURLConnection after a request may free network resources associated with this instance but has no effect on any shared persistent connection. Calling the disconnect() method may close the underlying socket if a persistent connection is otherwise idle at that time.
Field Summary | |
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protected int |
chunkLength
The chunk-length when using chunked encoding streaming mode for output. |
protected int |
fixedContentLength
The fixed content-length when using fixed-length streaming mode. |
static int |
HTTP_ACCEPTED
HTTP Status-Code 202: Accepted. |
static int |
HTTP_BAD_GATEWAY
HTTP Status-Code 502: Bad Gateway. |
static int |
HTTP_BAD_METHOD
HTTP Status-Code 405: Method Not Allowed. |
static int |
HTTP_BAD_REQUEST
HTTP Status-Code 400: Bad Request. |
static int |
HTTP_CLIENT_TIMEOUT
HTTP Status-Code 408: Request Time-Out. |
static int |
HTTP_CONFLICT
HTTP Status-Code 409: Conflict. |
static int |
HTTP_CREATED
HTTP Status-Code 201: Created. |
static int |
HTTP_ENTITY_TOO_LARGE
HTTP Status-Code 413: Request Entity Too Large. |
static int |
HTTP_FORBIDDEN
HTTP Status-Code 403: Forbidden. |
static int |
HTTP_GATEWAY_TIMEOUT
HTTP Status-Code 504: Gateway Timeout. |
static int |
HTTP_GONE
HTTP Status-Code 410: Gone. |
static int |
HTTP_INTERNAL_ERROR
HTTP Status-Code 500: Internal Server Error. |
static int |
HTTP_LENGTH_REQUIRED
HTTP Status-Code 411: Length Required. |
static int |
HTTP_MOVED_PERM
HTTP Status-Code 301: Moved Permanently. |
static int |
HTTP_MOVED_TEMP
HTTP Status-Code 302: Temporary Redirect. |
static int |
HTTP_MULT_CHOICE
HTTP Status-Code 300: Multiple Choices. |
static int |
HTTP_NO_CONTENT
HTTP Status-Code 204: No Content. |
static int |
HTTP_NOT_ACCEPTABLE
HTTP Status-Code 406: Not Acceptable. |
static int |
HTTP_NOT_AUTHORITATIVE
HTTP Status-Code 203: Non-Authoritative Information. |
static int |
HTTP_NOT_FOUND
HTTP Status-Code 404: Not Found. |
static int |
HTTP_NOT_IMPLEMENTED
HTTP Status-Code 501: Not Implemented. |
static int |
HTTP_NOT_MODIFIED
HTTP Status-Code 304: Not Modified. |
static int |
HTTP_OK
HTTP Status-Code 200: OK. |
static int |
HTTP_PARTIAL
HTTP Status-Code 206: Partial Content. |
static int |
HTTP_PAYMENT_REQUIRED
HTTP Status-Code 402: Payment Required. |
static int |
HTTP_PRECON_FAILED
HTTP Status-Code 412: Precondition Failed. |
static int |
HTTP_PROXY_AUTH
HTTP Status-Code 407: Proxy Authentication Required. |
static int |
HTTP_REQ_TOO_LONG
HTTP Status-Code 414: Request-URI Too Large. |
static int |
HTTP_RESET
HTTP Status-Code 205: Reset Content. |
static int |
HTTP_SEE_OTHER
HTTP Status-Code 303: See Other. |
static int |
HTTP_SERVER_ERROR
Deprecated. it is misplaced and shouldn't have existed. |
static int |
HTTP_UNAUTHORIZED
HTTP Status-Code 401: Unauthorized. |
static int |
HTTP_UNAVAILABLE
HTTP Status-Code 503: Service Unavailable. |
static int |
HTTP_UNSUPPORTED_TYPE
HTTP Status-Code 415: Unsupported Media Type. |
static int |
HTTP_USE_PROXY
HTTP Status-Code 305: Use Proxy. |
static int |
HTTP_VERSION
HTTP Status-Code 505: HTTP Version Not Supported. |
protected boolean |
instanceFollowRedirects
If true, the protocol will automatically follow redirects. |
protected String |
method
The HTTP method (GET,POST,PUT,etc.). |
protected int |
responseCode
An int representing the three digit HTTP Status-Code. |
protected String |
responseMessage
The HTTP response message. |
Fields inherited from class java.net. URLConnection |
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allowUserInteraction , connected , doInput , doOutput , ifModifiedSince , url , useCaches |
Constructor Summary | |
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protected |
HttpURLConnection
(
URL
u) Constructor for the HttpURLConnection. |
Method Summary | |
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abstract void |
disconnect
() Indicates that other requests to the server are unlikely in the near future. |
InputStream |
getErrorStream
() Returns the error stream if the connection failed but the server sent useful data nonetheless. |
static boolean |
getFollowRedirects
() Returns a boolean indicating whether or not HTTP redirects (3xx) should be automatically followed. |
String |
getHeaderField
(int n) Returns the value for the n th header field. |
long |
getHeaderFieldDate
(
String
name, long Default) Returns the value of the named field parsed as date. |
String |
getHeaderFieldKey
(int n) Returns the key for the n th header field. |
boolean |
getInstanceFollowRedirects
() Returns the value of this HttpURLConnection's instanceFollowRedirects field. |
Permission |
getPermission
() Returns a permission object representing the permission necessary to make the connection represented by this object. |
String |
getRequestMethod
() Get the request method. |
int |
getResponseCode
() Gets the status code from an HTTP response message. |
String |
getResponseMessage
() Gets the HTTP response message, if any, returned along with the response code from a server. |
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. |
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. |
static void |
setFollowRedirects
(boolean set) Sets whether HTTP redirects (requests with response code 3xx) should be automatically followed by this class. |
void |
setInstanceFollowRedirects
(boolean followRedirects) Sets whether HTTP redirects (requests with response code 3xx) should be automatically followed by this HttpURLConnection instance. |
void |
setRequestMethod
(
String
method) Set the method for the URL request, one of: GET POST HEAD OPTIONS PUT DELETE TRACE are legal, subject to protocol restrictions. |
abstract boolean |
usingProxy
() Indicates if the connection is going through a proxy. |
Methods inherited from class java.lang. Object |
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clone , equals , finalize , getClass , hashCode , notify , notifyAll , wait , wait , wait |
Field Detail |
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protected String method
protected int chunkLength
protected int fixedContentLength
protected int responseCode
protected String responseMessage
protected boolean instanceFollowRedirects
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.
public static final int HTTP_OK
public static final int HTTP_CREATED
public static final int HTTP_ACCEPTED
public static final int HTTP_NOT_AUTHORITATIVE
public static final int HTTP_NO_CONTENT
public static final int HTTP_RESET
public static final int HTTP_PARTIAL
public static final int HTTP_MULT_CHOICE
public static final int HTTP_MOVED_PERM
public static final int HTTP_MOVED_TEMP
public static final int HTTP_SEE_OTHER
public static final int HTTP_NOT_MODIFIED
public static final int HTTP_USE_PROXY
public static final int HTTP_BAD_REQUEST
public static final int HTTP_UNAUTHORIZED
public static final int HTTP_PAYMENT_REQUIRED
public static final int HTTP_FORBIDDEN
public static final int HTTP_NOT_FOUND
public static final int HTTP_BAD_METHOD
public static final int HTTP_NOT_ACCEPTABLE
public static final int HTTP_PROXY_AUTH
public static final int HTTP_CLIENT_TIMEOUT
public static final int HTTP_CONFLICT
public static final int HTTP_GONE
public static final int HTTP_LENGTH_REQUIRED
public static final int HTTP_PRECON_FAILED
public static final int HTTP_ENTITY_TOO_LARGE
public static final int HTTP_REQ_TOO_LONG
public static final int HTTP_UNSUPPORTED_TYPE
@Deprecated public static final int HTTP_SERVER_ERROR
public static final int HTTP_INTERNAL_ERROR
public static final int HTTP_NOT_IMPLEMENTED
public static final int HTTP_BAD_GATEWAY
public static final int HTTP_UNAVAILABLE
public static final int HTTP_GATEWAY_TIMEOUT
public static final int HTTP_VERSION
Constructor Detail |
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protected HttpURLConnection(URL u)
Method Detail |
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public String getHeaderFieldKey(int n)
public void setFixedLengthStreamingMode(int contentLength)
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.
public void setChunkedStreamingMode(int chunklen)
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.
public String getHeaderField(int n)
This method can be used in conjunction with the getHeaderFieldKey method to iterate through all the headers in the message.
public static void setFollowRedirects(boolean set)
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.
public static boolean getFollowRedirects()
public void setInstanceFollowRedirects(boolean followRedirects)
The default value comes from followRedirects, which defaults to true.
public boolean getInstanceFollowRedirects()
public void setRequestMethod(String method) throws ProtocolException
public String getRequestMethod()
public int getResponseCode() throws IOException
HTTP/1.0 200 OK HTTP/1.0 401 UnauthorizedIt 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).
public String getResponseMessage() throws IOException
HTTP/1.0 200 OK HTTP/1.0 404 Not FoundExtracts the Strings "OK" and "Not Found" respectively. Returns null if none could be discerned from the responses (the result was not valid HTTP).
public long getHeaderFieldDate(String name, long Default)
This form of getHeaderField exists because some connection types (e.g., http-ng) have pre-parsed headers. Classes for that connection type can override this method and short-circuit the parsing.
public abstract void disconnect()
public abstract boolean usingProxy()
public Permission getPermission() throws IOException
The permission returned may dependent upon the state of the connection. For example, the permission before connecting may be different from that after connecting. For example, an HTTP sever, say foo.com, may redirect the connection to a different host, say bar.com. Before connecting the permission returned by the connection will represent the permission needed to connect to foo.com, while the permission returned after connecting will be to bar.com.
Permissions are generally used for two purposes: to protect caches of objects obtained through URLConnections, and to check the right of a recipient to learn about a particular URL. In the first case, the permission should be obtained after the object has been obtained. For example, in an HTTP connection, this will represent the permission to connect to the host from which the data was ultimately fetched. In the second case, the permission should be obtained and tested before connecting.
public InputStream getErrorStream()
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.