public abstract class

HttpURLConnection

extends URLConnection

java.lang.Object
↳	java.net.URLConnection
	↳	java.net.HttpURLConnection

Known Direct Subclasses

HttpsURLConnection

Class Overview

This abstract subclass of URLConnection defines method for managing HTTP connection according to the description given by RFC 2068

Summary

Constants
int	HTTP_ACCEPTED	Numeric status code, 202: Accepted
int	HTTP_BAD_GATEWAY	Numeric status code, 502: Bad Gateway
int	HTTP_BAD_METHOD	Numeric status code, 405: Bad Method
int	HTTP_BAD_REQUEST	Numeric status code, 400: Bad Request
int	HTTP_CLIENT_TIMEOUT	Numeric status code, 408: Client Timeout
int	HTTP_CONFLICT	Numeric status code, 409: Conflict
int	HTTP_CREATED	Numeric status code, 201: Created
int	HTTP_ENTITY_TOO_LARGE	Numeric status code, 413: Entity too large
int	HTTP_FORBIDDEN	Numeric status code, 403: Forbidden
int	HTTP_GATEWAY_TIMEOUT	Numeric status code, 504: Gateway timeout
int	HTTP_GONE	Numeric status code, 410: Gone
int	HTTP_INTERNAL_ERROR	Numeric status code, 500: Internal error
int	HTTP_LENGTH_REQUIRED	Numeric status code, 411: Length required
int	HTTP_MOVED_PERM	Numeric status code, 301 Moved permanently
int	HTTP_MOVED_TEMP	Numeric status code, 302: Moved temporarily
int	HTTP_MULT_CHOICE	Numeric status code, 300: Multiple choices
int	HTTP_NOT_ACCEPTABLE	Numeric status code, 406: Not acceptable
int	HTTP_NOT_AUTHORITATIVE	Numeric status code, 203: Not authoritative
int	HTTP_NOT_FOUND	Numeric status code, 404: Not found
int	HTTP_NOT_IMPLEMENTED	Numeric status code, 501: Not implemented
int	HTTP_NOT_MODIFIED	Numeric status code, 304: Not modified
int	HTTP_NO_CONTENT	Numeric status code, 204: No content
int	HTTP_OK	Numeric status code, 200: OK
int	HTTP_PARTIAL	Numeric status code, 206: Partial
int	HTTP_PAYMENT_REQUIRED	Numeric status code, 402: Payment required
int	HTTP_PRECON_FAILED	Numeric status code, 412: Precondition failed
int	HTTP_PROXY_AUTH	Numeric status code, 407: Proxy authentication required
int	HTTP_REQ_TOO_LONG	Numeric status code, 414: Request too long
int	HTTP_RESET	Numeric status code, 205: Reset
int	HTTP_SEE_OTHER	Numeric status code, 303: See other
int	HTTP_SERVER_ERROR	This constant is deprecated. Use HTTP_INTERNAL_ERROR
int	HTTP_UNAUTHORIZED	Numeric status code, 401: Unauthorized
int	HTTP_UNAVAILABLE	Numeric status code, 503: Unavailable
int	HTTP_UNSUPPORTED_TYPE	Numeric status code, 415: Unsupported type
int	HTTP_USE_PROXY	Numeric status code, 305: Use proxy
int	HTTP_VERSION	Numeric status code, 505: Version not supported

Fields
protected int	chunkLength
protected int	fixedContentLength
protected boolean	instanceFollowRedirects
protected String	method
protected int	responseCode
protected String	responseMessage

[Expand]

Inherited Fields

From class java.net.URLConnection

Protected Constructors
	HttpURLConnection(URL url) Constructs a `HttpURLConnection` pointing to the resource specified by the `URL`.

Public Methods
abstract void	disconnect() Closes the connection with the HTTP server
InputStream	getErrorStream() Returns a input stream from the server in the case of error such as the requested file (txt, htm, html) is not found on the remote server.
static boolean	getFollowRedirects() Returns the value of `followRedirects` which indicates if this connection will follows a different URL redirected by the server.
long	getHeaderFieldDate(String field, long defaultValue) Returns the date value in the form of milliseconds since epoch corresponding to the field `field`.
boolean	getInstanceFollowRedirects() Returns if this connection follows redirects.
Permission	getPermission() Returns the permission object (in this case, SocketPermission) with the host and the port number as the target name and "resolve, connect" as the action list.
String	getRequestMethod() Returns the request method which will be used to make the request to the remote HTTP server.
int	getResponseCode() Returns the response code returned by the remote HTTP server
String	getResponseMessage() Returns the response message returned the remote HTTP server
void	setChunkedStreamingMode(int chunklen) If length of a HTTP request body is NOT known ahead, enable chunked transfer encoding to enable streaming without buffering.
void	setFixedLengthStreamingMode(int contentLength) If length of a HTTP request body is known ahead, sets fixed length to enable streaming without buffering.
static void	setFollowRedirects(boolean auto) Sets the flag of whether this connection will follow redirects returned by the remote server.
void	setInstanceFollowRedirects(boolean followRedirects) Sets if this connection follows redirects.
void	setRequestMethod(String method) Sets the request command which will be sent to the remote HTTP server.
abstract boolean	usingProxy() Returns if this connection uses proxy.

[Expand]

Inherited Methods

From class java.net.URLConnection

void	addRequestProperty(String field, String newValue) Adds the given request property.
abstract void	connect() Establishes the connection to the resource specified by this `URL` with this `method`, along with other options that can only be set before this connection is made.
boolean	getAllowUserInteraction() Returns the value of `allowUserInteraction` which indicates if this connection allows user interaction
int	getConnectTimeout() Returns a timeout of connection by milliseconds
Object	getContent(Class[] types) Returns the object pointed to by this `URL`.
Object	getContent() Returns the object pointed to by this `URL`.
String	getContentEncoding() Returns the Content encoding type of the response body, null if no such field is found in the header response.
int	getContentLength() Returns the length of the content or body in the response header in bytes.
String	getContentType() Returns the type of the content.
long	getDate() Returns the date in milliseconds since epoch when this response header was created, or 0 if the field `Date` is not found in the header.
static boolean	getDefaultAllowUserInteraction() Returns whether this connection allow user interaction by default.
static String	getDefaultRequestProperty(String field) This method is deprecated. Use getRequestProperty(String)
boolean	getDefaultUseCaches() Returns whether this connection use caches by default.
boolean	getDoInput() Returns whether this connection supports input.
boolean	getDoOutput() Returns whether this connection supports output.
long	getExpiration() Returns the date in milliseconds since epoch when this response header expires or 0 if the field `Expires` is not found in the header.
static FileNameMap	getFileNameMap() Returns the MIME table of this URL connection.
String	getHeaderField(int pos) Returns the value of the field at position `pos.`
String	getHeaderField(String key) Returns the value of the field corresponding to the `key` Returns `null` if there is no such field.
long	getHeaderFieldDate(String field, long defaultValue) Returns the date value in the form of milliseconds since epoch corresponding to the field `field`.
int	getHeaderFieldInt(String field, int defaultValue) Returns the integer value of the specified field.
String	getHeaderFieldKey(int posn) Returns the name of the field at position specified by `posn`, null if there are fewer than `posn` fields.
Map<String, List<String>>	getHeaderFields() Provides an unmodifiable map of the connection header values.
long	getIfModifiedSince() Returns the value of `ifModifiedSince` of this connection in milliseconds since epoch
InputStream	getInputStream() Creates an InputStream for reading from this URL Connection.
long	getLastModified() Returns the value of the field `Last-Modified` in the response header, 0 if no such field exists
OutputStream	getOutputStream() Creates an OutputStream for writing to this URL Connection.
Permission	getPermission() Returns the permissions necessary to make the connection.
int	getReadTimeout() Returns a timeout of reading by milliseconds
Map<String, List<String>>	getRequestProperties() Provides an unmodifiable map of the request properties.
String	getRequestProperty(String field) Returns the value corresponding to the field in the request Header, null if no such field exists.
URL	getURL() Returns the `URL` of this connection
boolean	getUseCaches() Returns whether this connection uses caches
static String	guessContentTypeFromName(String url) Determines the MIME type of the file specified by the `string` URL, using the filename extension.
static String	guessContentTypeFromStream(InputStream is) Examines the bytes of the input stream and returns the MIME type, null if no content type can be deduced.
void	setAllowUserInteraction(boolean newValue) Sets the flag indicating whether this connection allows user interaction This can only be called prior to connection establishment.
void	setConnectTimeout(int timeout) Sets a timeout for connection to perform non-block.
synchronized static void	setContentHandlerFactory(ContentHandlerFactory contentFactory) Sets the current content handler factory to be `contentFactory`.
static void	setDefaultAllowUserInteraction(boolean allows) Set whether user interaction is allowed by default.
static void	setDefaultRequestProperty(String field, String value) This method is deprecated. Use getRequestProperty(String)
void	setDefaultUseCaches(boolean newValue) Set whether caches are used by default.
void	setDoInput(boolean newValue) Sets whether this URLConnection allows input.
void	setDoOutput(boolean newValue) Sets whether this URLConnection allows output.
static void	setFileNameMap(FileNameMap map) With permission from the security manager, this method sets the `map` to be the MIME Table of this URL connection.
void	setIfModifiedSince(long newValue) Sets the header field `ifModifiedSince`.
void	setReadTimeout(int timeout) Sets a timeout for reading to perform non-block.
void	setRequestProperty(String field, String newValue) Sets the value of the request header field `field` to `newValue` Only the current URL Connection is affected.
void	setUseCaches(boolean newValue) Sets the flag indicating if this connection uses caches.
String	toString() Returns the name of the class of the `URLConnection`

From class java.lang.Object

Object	clone() Returns a new instance of the same class as the receiver, whose slots have been filled in with the values in the slots of the receiver.
boolean	equals(Object o) Compares the argument to the receiver, and returns true if they represent the same object using a class specific comparison.
void	finalize() Called by the virtual machine when there are no longer any (non-weak) references to the receiver.
final Class<? extends Object>	getClass() Returns the unique instance of java.lang.Class which represents the class of the receiver.
int	hashCode() Returns an integer hash code for the receiver.
final void	notify() Causes one thread which is `wait` ing on the receiver to be made ready to run.
final void	notifyAll() Causes all threads which are `wait` ing on the receiver to be made ready to run.
String	toString() Returns a string containing a concise, human-readable description of the receiver.
final void	wait(long time, int frac) Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by `notify` or `notifyAll`) or the expiration of the timeout.
final void	wait(long time) Causes the thread which sent this message to be made not ready to run either pending some change in the receiver (as indicated by `notify` or `notifyAll`) or the expiration of the timeout.
final void	wait() Causes the thread which sent this message to be made not ready to run pending some change in the receiver (as indicated by `notify` or `notifyAll`).

Constants

public static final int HTTP_ACCEPTED

Numeric status code, 202: Accepted

Constant Value: 202 (0x000000ca)

public static final int HTTP_BAD_GATEWAY

Numeric status code, 502: Bad Gateway

Constant Value: 502 (0x000001f6)

public static final int HTTP_BAD_METHOD

Numeric status code, 405: Bad Method

Constant Value: 405 (0x00000195)

public static final int HTTP_BAD_REQUEST

Numeric status code, 400: Bad Request

Constant Value: 400 (0x00000190)

public static final int HTTP_CLIENT_TIMEOUT

Numeric status code, 408: Client Timeout

Constant Value: 408 (0x00000198)

public static final int HTTP_CONFLICT

Numeric status code, 409: Conflict

Constant Value: 409 (0x00000199)

public static final int HTTP_CREATED

Numeric status code, 201: Created

Constant Value: 201 (0x000000c9)

public static final int HTTP_ENTITY_TOO_LARGE

Numeric status code, 413: Entity too large

Constant Value: 413 (0x0000019d)

public static final int HTTP_FORBIDDEN

Numeric status code, 403: Forbidden

Constant Value: 403 (0x00000193)

public static final int HTTP_GATEWAY_TIMEOUT

Numeric status code, 504: Gateway timeout

Constant Value: 504 (0x000001f8)

public static final int HTTP_GONE

Numeric status code, 410: Gone

Constant Value: 410 (0x0000019a)

public static final int HTTP_INTERNAL_ERROR

Numeric status code, 500: Internal error

Constant Value: 500 (0x000001f4)

public static final int HTTP_LENGTH_REQUIRED

Numeric status code, 411: Length required

Constant Value: 411 (0x0000019b)

public static final int HTTP_MOVED_PERM

Numeric status code, 301 Moved permanently

Constant Value: 301 (0x0000012d)

public static final int HTTP_MOVED_TEMP

Numeric status code, 302: Moved temporarily

Constant Value: 302 (0x0000012e)

public static final int HTTP_MULT_CHOICE

Numeric status code, 300: Multiple choices

Constant Value: 300 (0x0000012c)

public static final int HTTP_NOT_ACCEPTABLE

Numeric status code, 406: Not acceptable

Constant Value: 406 (0x00000196)

public static final int HTTP_NOT_AUTHORITATIVE

Numeric status code, 203: Not authoritative

Constant Value: 203 (0x000000cb)

public static final int HTTP_NOT_FOUND

Numeric status code, 404: Not found

Constant Value: 404 (0x00000194)

public static final int HTTP_NOT_IMPLEMENTED

Numeric status code, 501: Not implemented

Constant Value: 501 (0x000001f5)

public static final int HTTP_NOT_MODIFIED

Numeric status code, 304: Not modified

Constant Value: 304 (0x00000130)

public static final int HTTP_NO_CONTENT

Numeric status code, 204: No content

Constant Value: 204 (0x000000cc)

public static final int HTTP_OK

Numeric status code, 200: OK

Constant Value: 200 (0x000000c8)

public static final int HTTP_PARTIAL

Numeric status code, 206: Partial

Constant Value: 206 (0x000000ce)

public static final int HTTP_PAYMENT_REQUIRED

Numeric status code, 402: Payment required

Constant Value: 402 (0x00000192)

public static final int HTTP_PRECON_FAILED

Numeric status code, 412: Precondition failed

Constant Value: 412 (0x0000019c)

public static final int HTTP_PROXY_AUTH

Numeric status code, 407: Proxy authentication required

Constant Value: 407 (0x00000197)

public static final int HTTP_REQ_TOO_LONG

Numeric status code, 414: Request too long

Constant Value: 414 (0x0000019e)

public static final int HTTP_RESET

Numeric status code, 205: Reset

Constant Value: 205 (0x000000cd)

public static final int HTTP_SEE_OTHER

Numeric status code, 303: See other

Constant Value: 303 (0x0000012f)

public static final int HTTP_SERVER_ERROR

This constant is deprecated.Use HTTP_INTERNAL_ERROR

Constant Value: 500 (0x000001f4)

public static final int HTTP_UNAUTHORIZED

Numeric status code, 401: Unauthorized

Constant Value: 401 (0x00000191)

public static final int HTTP_UNAVAILABLE

Numeric status code, 503: Unavailable

Constant Value: 503 (0x000001f7)

public static final int HTTP_UNSUPPORTED_TYPE

Numeric status code, 415: Unsupported type

Constant Value: 415 (0x0000019f)

public static final int HTTP_USE_PROXY

Numeric status code, 305: Use proxy

Constant Value: 305 (0x00000131)

public static final int HTTP_VERSION

Numeric status code, 505: Version not supported

Constant Value: 505 (0x000001f9)

Fields

protected int chunkLength

protected int fixedContentLength

protected boolean instanceFollowRedirects

protected String method

protected int responseCode

protected String responseMessage

Protected Constructors

protected HttpURLConnection (URL url)

Constructs a HttpURLConnection pointing to the resource specified by the URL.

Parameters

url	the URL of this connection

Public Methods

public abstract void disconnect ()

Closes the connection with the HTTP server

public InputStream getErrorStream ()

Returns a input stream from the server in the case of error such as the requested file (txt, htm, html) is not found on the remote server.

If the content type is not what stated above, FileNotFoundException is thrown.

Returns

the error input stream returned by the server.

public static boolean getFollowRedirects ()

Returns the value of followRedirects which indicates if this connection will follows a different URL redirected by the server. It is enabled by default.

Returns

The value of the flag

public long getHeaderFieldDate (String field, long defaultValue)

Returns the date value in the form of milliseconds since epoch corresponding to the field field. Returns defaultValue if no such field can be found in the response header.

Parameters

field	the field in question
defaultValue	the default value if no field is found

Returns

milliseconds since epoch

public boolean getInstanceFollowRedirects ()

Returns if this connection follows redirects.

Returns

true if this connection follows redirects, false otherwise.

public Permission getPermission ()

Returns the permission object (in this case, SocketPermission) with the host and the port number as the target name and "resolve, connect" as the action list.

Returns

the permission object required for this connection

Throws

IOException	if an IO exception occurs during the creation of the permission object.

public String getRequestMethod ()

Returns the request method which will be used to make the request to the remote HTTP server. All possible methods of this HTTP implementation is listed in the class definition.

Returns

the request method string

public int getResponseCode ()

Returns the response code returned by the remote HTTP server

Returns

the response code, -1 if no valid response code

Throws

IOException	if there is an IO error during the retrieval.

public String getResponseMessage ()

Returns the response message returned the remote HTTP server

Returns

the response message. null if such response exists

Throws

IOException	if there is an IO error during the retrieval.

public void setChunkedStreamingMode (int chunklen)

If length of a HTTP request body is NOT known ahead, enable chunked transfer encoding to enable streaming without buffering. Notice that not all http servers support this mode. Sets after connection will cause an exception.

Parameters

chunklen	the length of a chunk

Throws

IllegalStateException	if already connected or other mode already set

public void setFixedLengthStreamingMode (int contentLength)

If length of a HTTP request body is known ahead, sets fixed length to enable streaming without buffering. Sets after connection will cause an exception.

Parameters

contentLength	the fixed length of the HTTP request body

Throws

IllegalStateException	if already connected or other mode already set
IllegalArgumentException	if contentLength is less than zero

public static void setFollowRedirects (boolean auto)

Sets the flag of whether this connection will follow redirects returned by the remote server. This method can only be called with the permission from the security manager

Parameters

auto	The value to set

public void setInstanceFollowRedirects (boolean followRedirects)

Sets if this connection follows redirects.

Parameters

followRedirects	true if this connection should follows redirects, false otherwise.

public void setRequestMethod (String method)

Sets the request command which will be sent to the remote HTTP server. This method can only be called before the connection is made.

Parameters

method	The `non-null` string representing the method

Throws

ProtocolException	Thrown when this is called after connected, or the method is not supported by this HTTP implementation.

public abstract boolean usingProxy ()

Returns if this connection uses proxy.

Returns

true if this connection supports proxy, false otherwise.

Jan	FEB	Mar
	27
2008	2009	2010

Interfaces

Classes

Enums

Exceptions

HttpURLConnection

Class Overview

See Also

Summary

Constants

public static final int HTTP_ACCEPTED

public static final int HTTP_BAD_GATEWAY

public static final int HTTP_BAD_METHOD

public static final int HTTP_BAD_REQUEST

public static final int HTTP_CLIENT_TIMEOUT

public static final int HTTP_CONFLICT

public static final int HTTP_CREATED

public static final int HTTP_ENTITY_TOO_LARGE

public static final int HTTP_FORBIDDEN

public static final int HTTP_GATEWAY_TIMEOUT

public static final int HTTP_GONE

public static final int HTTP_INTERNAL_ERROR

public static final int HTTP_LENGTH_REQUIRED

public static final int HTTP_MOVED_PERM

public static final int HTTP_MOVED_TEMP

public static final int HTTP_MULT_CHOICE

public static final int HTTP_NOT_ACCEPTABLE

public static final int HTTP_NOT_AUTHORITATIVE

public static final int HTTP_NOT_FOUND

public static final int HTTP_NOT_IMPLEMENTED

public static final int HTTP_NOT_MODIFIED

public static final int HTTP_NO_CONTENT

public static final int HTTP_OK

public static final int HTTP_PARTIAL

public static final int HTTP_PAYMENT_REQUIRED

public static final int HTTP_PRECON_FAILED

public static final int HTTP_PROXY_AUTH

public static final int HTTP_REQ_TOO_LONG

public static final int HTTP_RESET

public static final int HTTP_SEE_OTHER

public static final int HTTP_SERVER_ERROR

public static final int HTTP_UNAUTHORIZED

public static final int HTTP_UNAVAILABLE

public static final int HTTP_UNSUPPORTED_TYPE

public static final int HTTP_USE_PROXY

public static final int HTTP_VERSION

Fields

protected int chunkLength

protected int fixedContentLength

protected boolean instanceFollowRedirects

protected String method

protected int responseCode

protected String responseMessage

Protected Constructors

protected HttpURLConnection (URL url)

Parameters

See Also

Public Methods

public abstract void disconnect ()

See Also

public InputStream getErrorStream ()

Returns

public static boolean getFollowRedirects ()

Returns

See Also

public long getHeaderFieldDate (String field, long defaultValue)

Parameters

Returns

public boolean getInstanceFollowRedirects ()

Returns

public Permission getPermission ()

Returns

Throws

public String getRequestMethod ()

Returns

See Also

public int getResponseCode ()

Returns

Throws

See Also

public String getResponseMessage ()