public abstract Class HttpURLConnection

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.

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.

Returns:InputStream

an error stream if any, null if there have been no errors, the connection is not connected or the server sent no useful data.

Returns a boolean indicating whether or not HTTP redirects (3xx) should be automatically followed.

Returns:boolean

true if HTTP redirects should be automatically followed, false if not.

See Also

setFollowRedirects(boolean)

Overrides java.net.URLConnection.getHeaderField.

Returns the value for the n^th header field. Some implementations may treat the 0^th header field as special, i.e. as the status line returned by the HTTP server.

This method can be used in conjunction with the getHeaderFieldKey method to iterate through all the headers in the message.

Parameters

n:int

an index, where n>=0.

Returns:String

the value of the n^th header field, or null if the value does not exist.

See Also

java.net.HttpURLConnection#getHeaderFieldKey(int)

Overrides java.net.URLConnection.getHeaderFieldDate.

Doc from java.net.URLConnection.getHeaderFieldDate.

Returns the value of the named field parsed as date. The result is the number of milliseconds since January 1, 1970 GMT represented by the named field.

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.

Annotations

@SuppressWarnings:deprecation

Overrides java.net.URLConnection.getHeaderFieldKey.

Returns the key for the n^th header field. Some implementations may treat the 0^th header field as special, i.e. as the status line returned by the HTTP server. In this case, getHeaderField(0) returns the status line, but getHeaderFieldKey(0) returns null.

Parameters

n:int

an index, where n >=0.

Returns:String

the key for the n^th header field, or null if the key does not exist.

Returns the value of this HttpURLConnection's instanceFollowRedirects field.

Returns:boolean

the value of this HttpURLConnection's instanceFollowRedirects field.

Since

1.3

See Also

java.net.HttpURLConnection#instanceFollowRedirects, setInstanceFollowRedirects(boolean)

Overrides java.net.URLConnection.getPermission.

Returns a SocketPermission object representing the permission necessary to connect to the destination host and port.

Returns:Permission

a SocketPermission object representing the permission necessary to connect to the destination host and port.

Annotations

@Deprecated

since:25

forRemoval:true

@SuppressWarnings:removal

Exceptions

IOException:

if an error occurs while computing the permission.

Get the request method.

Returns:String

the HTTP request method

See Also

setRequestMethod(java.lang.String)

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

Returns:int

the HTTP Status-Code, or -1

Exceptions

IOException:

if an error occurred connecting to the server.

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

Returns:String

the HTTP response message, or null

Exceptions

IOException:

if an error occurred connecting to the server.

Supplies an Authenticator to be used when authentication is requested through the HTTP protocol for this HttpURLConnection. If no authenticator is supplied, the default authenticator will be used.

Parameters

auth:Authenticator

The Authenticator that should be used by this HttpURLConnection.

Exceptions

UnsupportedOperationException:

if setting an Authenticator is not supported by the underlying implementation.

IllegalStateException:

if URLConnection is already connected.

NullPointerException:

if the supplied auth is null.

Since

9

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.

Parameters

chunklen:int

The number of bytes to be written in each chunk, including a chunk size header as a hexadecimal string (minimum of 1 byte), two CRLF's (4 bytes) and a minimum payload length of 1 byte. If chunklen is less than or equal to 5, a higher default value will be used.

Exceptions

IllegalStateException:

if URLConnection is already connected or if a different streaming mode is already enabled.

Since

1.5

See Also

setFixedLengthStreamingMode(int)

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.

Parameters

contentLength:int

The number of bytes which will be written to the OutputStream.

Exceptions

IllegalStateException:

if URLConnection is already connected or if a different streaming mode is already enabled.

IllegalArgumentException:

if a content length less than zero is specified.

Since

1.5

See Also

setChunkedStreamingMode(int)

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.

The content length set by invoking this method takes precedence over any value set by setFixedLengthStreamingMode(int).

Parameters

contentLength:long

The number of bytes which will be written to the OutputStream.

Exceptions

IllegalStateException:

if URLConnection is already connected or if a different streaming mode is already enabled.

IllegalArgumentException:

if a content length less than zero is specified.

Since

1.7

Sets whether HTTP redirects (requests with response code 3xx) should be automatically followed by this class. True by default.

Parameters

set:boolean

a boolean indicating whether or not to follow HTTP redirects.

See Also

getFollowRedirects()

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.

Parameters

followRedirects:boolean

a boolean indicating whether or not to follow HTTP redirects.

Since

1.3

See Also

java.net.HttpURLConnection#instanceFollowRedirects, getInstanceFollowRedirects

Set the method for the URL request, one of:

• GET
• POST
• HEAD
• OPTIONS
• PUT
• DELETE
• TRACE

Parameters

method:String

the HTTP method

Exceptions

ProtocolException:

if the method cannot be reset or if the requested method isn't valid for HTTP.

See Also

getRequestMethod()

Indicates if the connection is going through a proxy. This method returns true if the connection is known to be going or has gone through proxies, and returns false if the connection will never go through a proxy or if the use of a proxy cannot be determined.

Returns:boolean

a boolean indicating if the connection is using a proxy.