java.net
Class HttpURLConnection

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

public abstract class HttpURLConnection
extends URLConnection

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

See Also:

ContentHandler, URL, URLConnection, URLStreamHandler

Field Summary

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

Fields inherited from class java.net.URLConnection

allowUserInteraction, connected, doInput, doOutput, ifModifiedSince, url, useCaches

Constructor Summary

protected

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

Method Summary

abstract void	disconnect() Closes the connection with the HTTP server
InputStream	getErrorStream() Answers 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() Answers the value of followRedirects which indicates if this connection will follows a different URL redirected by the server.
long	getHeaderFieldDate(String field, long defaultValue) Answers the date value in the form of milliseconds since epoch corresponding to the field field.
boolean	getInstanceFollowRedirects() Answers if this connection follows redirects.
Permission	getPermission() Answers 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() Answers the request method which will be used to make the request to the remote HTTP server.
int	getResponseCode() Answers the reponse code returned by the remote HTTP server
String	getResponseMessage() Answers the response message returned the remote HTTP server
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() Answers if this connection uses proxy.

Methods inherited from class java.net.URLConnection

addRequestProperty, connect, getAllowUserInteraction, getContent, getContent, getContentEncoding, getContentLength, getContentType, getDate, getDefaultAllowUserInteraction, getDefaultRequestProperty, getDefaultUseCaches, getDoInput, getDoOutput, getExpiration, getFileNameMap, getHeaderField, getHeaderField, getHeaderFieldInt, getHeaderFieldKey, getHeaderFields, getIfModifiedSince, getInputStream, getLastModified, getOutputStream, getRequestProperties, getRequestProperty, getURL, getUseCaches, guessContentTypeFromName, guessContentTypeFromStream, setAllowUserInteraction, setContentHandlerFactory, setDefaultAllowUserInteraction, setDefaultRequestProperty, setDefaultUseCaches, setDoInput, setDoOutput, setFileNameMap, setIfModifiedSince, setRequestProperty, setUseCaches, toString

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, wait, wait, wait

Field Detail

method

protected String method

responseCode

protected int responseCode

responseMessage

protected String responseMessage

instanceFollowRedirects

protected boolean instanceFollowRedirects

HTTP_ACCEPTED

public static final int HTTP_ACCEPTED

Numeric status code, 202: Accepted

See Also:

Constant Field Values

HTTP_BAD_GATEWAY

public static final int HTTP_BAD_GATEWAY

Numeric status code, 502: Bad Gateway

See Also:

Constant Field Values

HTTP_BAD_METHOD

public static final int HTTP_BAD_METHOD

Numeric status code, 405: Bad Method

See Also:

Constant Field Values

HTTP_BAD_REQUEST

public static final int HTTP_BAD_REQUEST

Numeric status code, 400: Bad Request

See Also:

Constant Field Values

HTTP_CLIENT_TIMEOUT

public static final int HTTP_CLIENT_TIMEOUT

Numeric status code, 408: Client Timeout

See Also:

Constant Field Values

HTTP_CONFLICT

public static final int HTTP_CONFLICT

Numeric status code, 409: Conflict

See Also:

Constant Field Values

HTTP_CREATED

public static final int HTTP_CREATED

Numeric status code, 201: Created

See Also:

Constant Field Values

HTTP_ENTITY_TOO_LARGE

public static final int HTTP_ENTITY_TOO_LARGE

Numeric status code, 413: Entity too large

See Also:

Constant Field Values

HTTP_FORBIDDEN

public static final int HTTP_FORBIDDEN

Numeric status code, 403: Forbidden

See Also:

Constant Field Values

HTTP_GATEWAY_TIMEOUT

public static final int HTTP_GATEWAY_TIMEOUT

Numeric status code, 504: atewaytimeout

See Also:

Constant Field Values

HTTP_GONE

public static final int HTTP_GONE

Numeric status code, 410: Gone

See Also:

Constant Field Values

HTTP_INTERNAL_ERROR

public static final int HTTP_INTERNAL_ERROR

Numeric status code, 500: Internal error

See Also:

Constant Field Values

HTTP_LENGTH_REQUIRED

public static final int HTTP_LENGTH_REQUIRED

Numeric status code, 411: Length required

See Also:

Constant Field Values

HTTP_MOVED_PERM

public static final int HTTP_MOVED_PERM

Numeric status code, 301 Moved permanently

See Also:

Constant Field Values

HTTP_MOVED_TEMP

public static final int HTTP_MOVED_TEMP

Numeric status code, 302: Moved temporarily

See Also:

Constant Field Values

HTTP_MULT_CHOICE

public static final int HTTP_MULT_CHOICE

Numeric status code, 300: Multiple choices

See Also:

Constant Field Values

HTTP_NO_CONTENT

public static final int HTTP_NO_CONTENT

Numeric status code, 204: No content

See Also:

Constant Field Values

HTTP_NOT_ACCEPTABLE

public static final int HTTP_NOT_ACCEPTABLE

Numeric status code, 406: Not acceptable

See Also:

Constant Field Values

HTTP_NOT_AUTHORITATIVE

public static final int HTTP_NOT_AUTHORITATIVE

Numeric status code, 203: Not authoritative

See Also:

Constant Field Values

HTTP_NOT_FOUND

public static final int HTTP_NOT_FOUND

Numeric status code, 404: Not found

See Also:

Constant Field Values

HTTP_NOT_IMPLEMENTED

public static final int HTTP_NOT_IMPLEMENTED

Numeric status code, 501: Not implemented

See Also:

Constant Field Values

HTTP_NOT_MODIFIED

public static final int HTTP_NOT_MODIFIED

Numeric status code, 304: Not modified

See Also:

Constant Field Values

HTTP_OK

public static final int HTTP_OK

Numeric status code, 200: OK

See Also:

Constant Field Values

HTTP_PARTIAL

public static final int HTTP_PARTIAL

Numeric status code, 206: Partial

See Also:

Constant Field Values

HTTP_PAYMENT_REQUIRED

public static final int HTTP_PAYMENT_REQUIRED

Numeric status code, 402: Payment required

See Also:

Constant Field Values

HTTP_PRECON_FAILED

public static final int HTTP_PRECON_FAILED

Numeric status code, 412: Precondition failed

See Also:

Constant Field Values

HTTP_PROXY_AUTH

public static final int HTTP_PROXY_AUTH

Numeric status code, 407: Proxy authentication required

See Also:

Constant Field Values

HTTP_REQ_TOO_LONG

public static final int HTTP_REQ_TOO_LONG

Numeric status code, 414: Request too long

See Also:

Constant Field Values

HTTP_RESET

public static final int HTTP_RESET

Numeric status code, 205: Reset

See Also:

Constant Field Values

HTTP_SEE_OTHER

public static final int HTTP_SEE_OTHER

Numeric status code, 303: See other

See Also:

Constant Field Values

HTTP_SERVER_ERROR

public static final int HTTP_SERVER_ERROR

Deprecated. Use HTTP_INTERNAL_ERROR

See Also:

Constant Field Values

HTTP_USE_PROXY

public static final int HTTP_USE_PROXY

Numeric status code, 305: Use proxy

See Also:

Constant Field Values

HTTP_UNAUTHORIZED

public static final int HTTP_UNAUTHORIZED

Numeric status code, 401: Unauthorized

See Also:

Constant Field Values

HTTP_UNSUPPORTED_TYPE

public static final int HTTP_UNSUPPORTED_TYPE

Numeric status code, 415: Unsupported type

See Also:

Constant Field Values

HTTP_UNAVAILABLE

public static final int HTTP_UNAVAILABLE

Numeric status code, 503: Unavailable

See Also:

Constant Field Values

HTTP_VERSION

public static final int HTTP_VERSION

Numeric status code, 505: Version not supported

See Also:

Constant Field Values

Constructor Detail

HttpURLConnection

protected HttpURLConnection(URL url)

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

Parameters:

url - the URL of this connection

See Also:

URL, URLConnection

Method Detail

disconnect

public abstract void disconnect()

Closes the connection with the HTTP server

See Also:

URLConnection.connect(), URLConnection.connected

getErrorStream

public InputStream getErrorStream()

Answers 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.

getFollowRedirects

public static boolean getFollowRedirects()

Answers 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

See Also:

setFollowRedirects(boolean)

getPermission

public Permission getPermission()
                         throws IOException

Answers 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.

Overrides:

getPermission in class URLConnection

Returns:

the permission object required for this connection

Throws:

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

getRequestMethod

public String getRequestMethod()

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

Returns:

the request method string

See Also:

method, setRequestMethod(java.lang.String)

getResponseCode

public int getResponseCode()
                    throws IOException

Answers the reponse 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.

See Also:

getResponseMessage()

getResponseMessage

public String getResponseMessage()
                          throws IOException

Answers 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.

See Also:

getResponseCode(), IOException

setFollowRedirects

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

See Also:

SecurityManager.checkSetFactory()

setRequestMethod

public void setRequestMethod(String method)
                      throws ProtocolException

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 impl.

See Also:

getRequestMethod(), method

usingProxy

public abstract boolean usingProxy()

Answers if this connection uses proxy.

Returns:

true if this connection supports proxy, false otherwise.

getInstanceFollowRedirects

public boolean getInstanceFollowRedirects()

Answers if this connection follows redirects.

Returns:

true if this connection follows redirects, false otherwise.

setInstanceFollowRedirects

public void setInstanceFollowRedirects(boolean followRedirects)

Sets if this connection follows redirects.

Parameters:

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

getHeaderFieldDate

public long getHeaderFieldDate(String field,
                               long defaultValue)

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

Overrides:

getHeaderFieldDate in class URLConnection

Parameters:

field - the field in question

defaultValue - the default value if no field is found

Returns:

milliseconds since epoch

See Also:

URLConnection.ifModifiedSince, URLConnection.setIfModifiedSince(long)