java.net
Class HttpURLConnection
java.lang.Object
|
+--java.net.URLConnection
|
+--java.net.HttpURLConnection
This class provides a common abstract implementation for those
URL connection classes that will connect using the HTTP protocol.
In addition to the functionality provided by the URLConnection
class, it defines constants for HTTP return code values and
methods for setting the HTTP request method and determining whether
or not to follow redirects.
Since:Authors:- Warren Levy (warrenl@cygnus.com)
- Aaron M. Renn (arenn@urbanophile.com)
HTTP_ACCEPTED
public static final int HTTP_ACCEPTED
The request has been accepted for processing but has not completed.
There is no guarantee that the requested action will actually ever
be completed succesfully, but everything is ok so far.
HTTP_BAD_GATEWAY
public static final int HTTP_BAD_GATEWAY
The proxy encountered a bad response from the server it was proxy-ing for
HTTP_BAD_METHOD
public static final int HTTP_BAD_METHOD
The specified request method is not allowed for this resource.
HTTP_BAD_REQUEST
public static final int HTTP_BAD_REQUEST
The request was misformed or could not be understood.
HTTP_CLIENT_TIMEOUT
public static final int HTTP_CLIENT_TIMEOUT
The request timed out.
HTTP_CONFLICT
public static final int HTTP_CONFLICT
There is a conflict between the current state of the resource and the
requested action.
HTTP_CREATED
public static final int HTTP_CREATED
The requested resource has been created.
HTTP_ENTITY_TOO_LARGE
public static final int HTTP_ENTITY_TOO_LARGE
The request sent was too large for the server to handle.
HTTP_FORBIDDEN
public static final int HTTP_FORBIDDEN
There is no permission to access the requested resource.
HTTP_GATEWAY_TIMEOUT
public static final int HTTP_GATEWAY_TIMEOUT
The proxy timed out getting a reply from the remote server it was
proxy-ing for.
HTTP_GONE
public static final int HTTP_GONE
The requested resource is no longer available. This ususally indicates
a permanent condition.
HTTP_INTERNAL_ERROR
public static final int HTTP_INTERNAL_ERROR
The server encountered an unexpected error (such as a CGI script crash)
that prevents the request from being fulfilled.
HTTP_LENGTH_REQUIRED
public static final int HTTP_LENGTH_REQUIRED
A Content-Length header is required for this request, but was not
supplied.
HTTP_MOVED_PERM
public static final int HTTP_MOVED_PERM
The resource has been permanently moved to a new location.
HTTP_MOVED_TEMP
public static final int HTTP_MOVED_TEMP
The resource requested has been temporarily moved to a new location.
HTTP_MULT_CHOICE
public static final int HTTP_MULT_CHOICE
There is a list of choices available for the requested resource.
HTTP_NOT_ACCEPTABLE
public static final int HTTP_NOT_ACCEPTABLE
Based on the input headers sent, the resource returned in response
to the request would not be acceptable to the client.
HTTP_NOT_AUTHORITATIVE
public static final int HTTP_NOT_AUTHORITATIVE
The meta-information returned in the header is not the actual data
from the original server, but may be from a local or other copy.
Normally this still indicates a successful completion.
HTTP_NOT_FOUND
public static final int HTTP_NOT_FOUND
The requested resource was not found.
HTTP_NOT_IMPLEMENTED
public static final int HTTP_NOT_IMPLEMENTED
The server does not support the requested functionality.
Since:
HTTP_NOT_MODIFIED
public static final int HTTP_NOT_MODIFIED
The document has not been modified since the criteria specified in
a conditional GET.
HTTP_NO_CONTENT
public static final int HTTP_NO_CONTENT
The server performed the request, but there is no data to send
back. This indicates that the user's display should not be changed.
HTTP_OK
public static final int HTTP_OK
Indicates the request succeeded.
HTTP_PARTIAL
public static final int HTTP_PARTIAL
The server completed the partial GET request for the resource.
HTTP_PAYMENT_REQUIRED
public static final int HTTP_PAYMENT_REQUIRED
Code reserved for future use - I hope way in the future.
HTTP_PRECON_FAILED
public static final int HTTP_PRECON_FAILED
A client specified pre-condition was not met on the server.
HTTP_PROXY_AUTH
public static final int HTTP_PROXY_AUTH
The client must authenticate with a proxy prior to attempting this
request.
HTTP_REQ_TOO_LONG
public static final int HTTP_REQ_TOO_LONG
The name of the resource specified was too long.
HTTP_RESET
public static final int HTTP_RESET
The server performed the request, but there is no data to sent back,
however, the user's display should be "reset" to clear out any form
fields entered.
HTTP_SEE_OTHER
public static final int HTTP_SEE_OTHER
The response to the request issued is available at another location.
HTTP_SERVER_ERROR
public static final int HTTP_SERVER_ERROR
This error code indicates that some sort of server error occurred.
HTTP_UNAUTHORIZED
public static final int HTTP_UNAUTHORIZED
The request made requires user authorization. Try again with
a correct authentication header.
HTTP_UNAVAILABLE
public static final int HTTP_UNAVAILABLE
The HTTP service is not availalble, such as because it is overloaded
and does not want additional requests.
HTTP_UNSUPPORTED_TYPE
public static final int HTTP_UNSUPPORTED_TYPE
The request is in a format not supported by the requested resource.
HTTP_USE_PROXY
public static final int HTTP_USE_PROXY
The requested resource needs to be accessed through a proxy.
HTTP_VERSION
public static final int HTTP_VERSION
This server does not support the protocol version requested.
instanceFollowRedirects
protected boolean instanceFollowRedirects
If this instance should follow redirect requests.
method
protected String method
The requested method in use for this connection. Default is GET.
responseCode
protected int responseCode
The response code received from the server
responseMessage
protected String responseMessage
The response message string received from the server.
HttpURLConnection
protected HttpURLConnection(java.net.URL url)
Create an HttpURLConnection for the specified URL
Parameters:
disconnect
public void disconnect()
Closes the connection to the server.
getErrorStream
public InputStream getErrorStream()
This method allows the caller to retrieve any data that might have
been sent despite the fact that an error occurred. For example, the
HTML page sent along with a 404 File Not Found error. If the socket
is not connected, or if no error occurred or no data was returned,
this method returns null
.
Returns:
- An
InputStream
for reading error data.
getFollowRedirects
public static boolean getFollowRedirects()
Returns a boolean indicating whether or not HTTP redirects will
automatically be followed or not.
Returns:
- true if redirects will be followed, false otherwise
getHeaderFieldDate
public long getHeaderFieldDate(java.lang.String key, long value)
Returns the value of the named field parsed as date
Parameters:
getInstanceFollowRedirects
public boolean getInstanceFollowRedirects()
Returns the value of this HttpURLConnection's instanceFollowRedirects
field
getPermission
public Permission getPermission()
Returns a permission object representing the permission necessary to make
the connection represented by this object
Throws:
getRequestMethod
public String getRequestMethod()
The request method currently in use for this connection.
Returns:
getResponseCode
public int getResponseCode()
Gets the status code from an HTTP response message, or -1 if
the response code could not be determined.
Note that all valid response codes have class variables
defined for them in this class.
Returns:
Throws:
getResponseMessage
public String getResponseMessage()
Gets the HTTP response message, if any, returned along with the
response code from a server. Null if no response message was set
or an error occured while connecting.
Returns:
Throws:
setFollowRedirects
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
Parameters:
Throws:
SecurityException
- If a security manager exists and its
checkSetFactory method doesn't allow the operation
setInstanceFollowRedirects
public void setInstanceFollowRedirects(boolean follow)
Sets the value of this HttpURLConnection's instanceFollowRedirects field
Parameters:
setRequestMethod
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
Parameters:
Throws:
ProtocolException
- If the method cannot be reset or if the
requested method isn't valid for HTTP
usingProxy
public boolean usingProxy()
Returns a boolean indicating whether or not this connection is going
through a proxy
Returns:
- true if through a proxy, false otherwise