sun.net.www.protocol.http

Class HttpURLConnection

java.lang.Object

java.net.URLConnection

java.net.HttpURLConnection

sun.net.www.protocol.http.HttpURLConnection

Direct Known Subclasses:

AbstractDelegateHttpsURLConnection

public class HttpURLConnection
extends HttpURLConnection

A class to represent an HTTP connection to a remote object.

Field Summary

Fields

Modifier and Type	Field and Description
protected Handler	handler
protected HttpClient	http
protected PrintStream	ps
static String	userAgent

Fields inherited from class java.net.HttpURLConnection

chunkLength, fixedContentLength, fixedContentLengthLong, HTTP_ACCEPTED, HTTP_BAD_GATEWAY, HTTP_BAD_METHOD, HTTP_BAD_REQUEST, HTTP_CLIENT_TIMEOUT, HTTP_CONFLICT, HTTP_CREATED, HTTP_ENTITY_TOO_LARGE, HTTP_FORBIDDEN, HTTP_GATEWAY_TIMEOUT, HTTP_GONE, HTTP_INTERNAL_ERROR, HTTP_LENGTH_REQUIRED, HTTP_MOVED_PERM, HTTP_MOVED_TEMP, HTTP_MULT_CHOICE, HTTP_NO_CONTENT, HTTP_NOT_ACCEPTABLE, HTTP_NOT_AUTHORITATIVE, HTTP_NOT_FOUND, HTTP_NOT_IMPLEMENTED, HTTP_NOT_MODIFIED, HTTP_OK, HTTP_PARTIAL, HTTP_PAYMENT_REQUIRED, HTTP_PRECON_FAILED, HTTP_PROXY_AUTH, HTTP_REQ_TOO_LONG, HTTP_RESET, HTTP_SEE_OTHER, HTTP_UNAUTHORIZED, HTTP_UNAVAILABLE, HTTP_UNSUPPORTED_TYPE, HTTP_USE_PROXY, HTTP_VERSION, instanceFollowRedirects, method, responseCode, responseMessage

Fields inherited from class java.net.URLConnection

allowUserInteraction, connected, doInput, doOutput, url, useCaches

Constructor Summary

Constructors

Modifier	Constructor and Description
	HttpURLConnection(URL u) this constructor is used by other protocol handlers such as ftp that want to use http to fetch urls on their behalf.
protected	HttpURLConnection(URL u, Handler handler)

Method Summary

Modifier and Type	Method and Description
void	addRequestProperty(String key, String value) Adds a general request property specified by a key-value pair.
void	connect() Opens a communications link to the resource referenced by this URL, if such a connection has not already been established.
void	disconnect() Disconnect from the server (public API)
int	getConnectTimeout() Returns setting for connect timeout.
InputStream	getErrorStream() Returns the error stream if the connection failed but the server sent useful data nonetheless.
String	getHeaderField(int n) Gets a header field by index.
String	getHeaderField(String name) Gets a header field by name.
String	getHeaderFieldKey(int n) Gets a header field by index.
Map<String,List<String>>	getHeaderFields() Returns an unmodifiable Map of the header fields.
InputStream	getInputStream() Returns an input stream that reads from this open connection.
protected HttpClient	getNewHttpClient(URL url, int connectTimeout)
OutputStream	getOutputStream() Returns an output stream that writes to this connection.
int	getReadTimeout() Returns setting for read timeout.
Map<String,List<String>>	getRequestProperties() Returns an unmodifiable Map of general request properties for this connection.
String	getRequestProperty(String key) Returns the value of the named general request property for this connection.
static InputStream	openConnectionCheckRedirects(URLConnection c) opens a stream allowing redirects only to the same host.
protected void	plainConnect()
void	setAuthenticationProperty(String key, String value)
void	setConnectTimeout(int timeout) Sets a specified timeout value, in milliseconds, to be used when opening a communications link to the resource referenced by this URLConnection.
protected void	setNewClient(URL url) Obtain a HttpsClient object.
void	setReadTimeout(int timeout) Sets the read timeout to a specified timeout, in milliseconds.
void	setRequestProperty(String key, String value) Sets request property.
boolean	streaming()
boolean	usingProxy() Indicates if the connection is going through a proxy.

Methods inherited from class java.net.HttpURLConnection

getFollowRedirects, getInstanceFollowRedirects, getPermission, getRequestMethod, getResponseCode, getResponseMessage, setChunkedStreamingMode, setFixedLengthStreamingMode, setFixedLengthStreamingMode, setFollowRedirects, setInstanceFollowRedirects, setRequestMethod

Methods inherited from class java.net.URLConnection

getAllowUserInteraction, getContent, getContent, getContentEncoding, getContentLength, getContentLengthLong, getContentType, getDefaultAllowUserInteraction, getDefaultUseCaches, getDoInput, getDoOutput, getHeaderFieldInt, getHeaderFieldLong, getURL, getUseCaches, setAllowUserInteraction, setContentHandlerFactory, setDefaultAllowUserInteraction, setDefaultUseCaches, setDoInput, setDoOutput, setUseCaches, toString

Methods inherited from class java.lang.Object

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

Field Detail

handler

protected Handler handler

http

@Nullable
protected HttpClient http

ps

@Nullable
protected PrintStream ps

userAgent

public static final String userAgent

Constructor Detail

HttpURLConnection

public HttpURLConnection(URL u)

this constructor is used by other protocol handlers such as ftp that want to use http to fetch urls on their behalf.

HttpURLConnection

protected HttpURLConnection(URL u,
                            Handler handler)

Method Detail

addRequestProperty

public void addRequestProperty(String key,
                               String value)

Adds a general request property specified by a key-value pair. This method will not overwrite existing values associated with the same key.

Overrides:

addRequestProperty in class URLConnection

Parameters:

key - the keyword by which the request is known (e.g., "accept").

value - the value associated with it.

Since:

1.4

See Also:

getRequestProperties()

connect

public void connect()
             throws IOException

Description copied from class: URLConnection

Opens a communications link to the resource referenced by this URL, if such a connection has not already been established.

If the connect method is called when the connection has already been opened (indicated by the connected field having the value true), the call is ignored.

URLConnection objects go through two phases: first they are created, then they are connected. After being created, and before being connected, various options can be specified (e.g., doInput and UseCaches). After connecting, it is an error to try to set them. Operations that depend on being connected, like getContentLength, will implicitly perform the connection, if necessary.

Specified by:

connect in class URLConnection

Throws:

IOException - if an I/O error occurs while opening the connection.

See Also:

URLConnection.connected, URLConnection.getConnectTimeout(), URLConnection.setConnectTimeout(int)

disconnect

public void disconnect()

Disconnect from the server (public API)

Specified by:

disconnect in class HttpURLConnection

getConnectTimeout

public int getConnectTimeout()

Returns setting for connect timeout.

0 return implies that the option is disabled (i.e., timeout of infinity).

Overrides:

getConnectTimeout in class URLConnection

Returns:

an int that indicates the connect timeout value in milliseconds

Since:

1.5

See Also:

URLConnection.setConnectTimeout(int), URLConnection.connect()

getErrorStream

@Nullable
public InputStream getErrorStream()

Description copied from class: HttpURLConnection

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.

Overrides:

getErrorStream in class HttpURLConnection

Returns:

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

getHeaderField

@Nullable
public String getHeaderField(int n)

Gets a header field by index. Returns null if not known.

Overrides:

getHeaderField in class HttpURLConnection

Parameters:

n - the index of the header field

Returns:

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

See Also:

HttpURLConnection.getHeaderFieldKey(int)

getHeaderField

@Nullable
public String getHeaderField(String name)

Gets a header field by name. Returns null if not known.

Overrides:

getHeaderField in class URLConnection

Parameters:

name - the name of the header field

Returns:

the value of the named header field, or null if there is no such field in the header.

getHeaderFieldKey

@Nullable
public String getHeaderFieldKey(int n)

Gets a header field by index. Returns null if not known.

Overrides:

getHeaderFieldKey in class HttpURLConnection

Parameters:

n - the index of the header field

Returns:

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

getHeaderFields

public Map<String,List<String>> getHeaderFields()

Returns an unmodifiable Map of the header fields. The Map keys are Strings that represent the response-header field names. Each Map value is an unmodifiable List of Strings that represents the corresponding field values.

Overrides:

getHeaderFields in class URLConnection

Returns:

a Map of header fields

Since:

1.4

getInputStream

public InputStream getInputStream()
                           throws IOException

Description copied from class: URLConnection

Returns an input stream that reads from this open connection. A SocketTimeoutException can be thrown when reading from the returned input stream if the read timeout expires before data is available for read.

Overrides:

getInputStream in class URLConnection

Returns:

an input stream that reads from this open connection.

Throws:

IOException - if an I/O error occurs while creating the input stream.

UnknownServiceException - if the protocol does not support input.

See Also:

URLConnection.setReadTimeout(int), URLConnection.getReadTimeout()

getNewHttpClient

protected HttpClient getNewHttpClient(URL url,
                                      int connectTimeout)
                               throws IOException

Throws:

IOException

getOutputStream

public OutputStream getOutputStream()
                             throws IOException

Description copied from class: URLConnection

Returns an output stream that writes to this connection.

Overrides:

getOutputStream in class URLConnection

Returns:

an output stream that writes to this connection.

Throws:

IOException - if an I/O error occurs while creating the output stream.

UnknownServiceException - if the protocol does not support output.

getReadTimeout

public int getReadTimeout()

Returns setting for read timeout. 0 return implies that the option is disabled (i.e., timeout of infinity).

Overrides:

getReadTimeout in class URLConnection

Returns:

an int that indicates the read timeout value in milliseconds

Since:

1.5

See Also:

URLConnection.setReadTimeout(int), InputStream.read()

getRequestProperties

public Map<String,List<String>> getRequestProperties()

Returns an unmodifiable Map of general request properties for this connection. The Map keys are Strings that represent the request-header field names. Each Map value is a unmodifiable List of Strings that represents the corresponding field values.

Overrides:

getRequestProperties in class URLConnection

Returns:

a Map of the general request properties for this connection.

Throws:

IllegalStateException - if already connected

Since:

1.4

getRequestProperty

@Nullable
public String getRequestProperty(@Nullable
                                           String key)

Description copied from class: URLConnection

Returns the value of the named general request property for this connection.

Overrides:

getRequestProperty in class URLConnection

Parameters:

key - the keyword by which the request is known (e.g., "Accept").

Returns:

the value of the named general request property for this connection. If key is null, then null is returned.

See Also:

URLConnection.setRequestProperty(java.lang.String, java.lang.String)

openConnectionCheckRedirects

public static InputStream openConnectionCheckRedirects(URLConnection c)
                                                throws IOException

opens a stream allowing redirects only to the same host.

Throws:

IOException

plainConnect

protected void plainConnect()
                     throws IOException

Throws:

IOException

setAuthenticationProperty

public void setAuthenticationProperty(String key,
                                      String value)

setConnectTimeout

public void setConnectTimeout(int timeout)

Description copied from class: URLConnection

Sets a specified timeout value, in milliseconds, to be used when opening a communications link to the resource referenced by this URLConnection. If the timeout expires before the connection can be established, a java.net.SocketTimeoutException is raised. A timeout of zero is interpreted as an infinite timeout.

Some non-standard implementation of this method may ignore the specified timeout. To see the connect timeout set, please call getConnectTimeout().

Overrides:

setConnectTimeout in class URLConnection

Parameters:

timeout - an int that specifies the connect timeout value in milliseconds

See Also:

URLConnection.getConnectTimeout(), URLConnection.connect()

setNewClient

protected void setNewClient(URL url)
                     throws IOException

Obtain a HttpsClient object. Use the cached copy if specified.

Parameters:

url - the URL being accessed

Throws:

IOException

setReadTimeout

public void setReadTimeout(int timeout)

Sets the read timeout to a specified timeout, in milliseconds. A non-zero value specifies the timeout when reading from Input stream when a connection is established to a resource. If the timeout expires before there is data available for read, a java.net.SocketTimeoutException is raised. A timeout of zero is interpreted as an infinite timeout.

Some non-standard implementation of this method ignores the specified timeout. To see the read timeout set, please call getReadTimeout().

Overrides:

setReadTimeout in class URLConnection

Parameters:

timeout - an int that specifies the timeout value to be used in milliseconds

Throws:

IllegalArgumentException - if the timeout parameter is negative

Since:

1.5

See Also:

InputStream.read()

setRequestProperty

public void setRequestProperty(String key,
                               String value)

Sets request property. If a property with the key already exists, overwrite its value with the new value.

Overrides:

setRequestProperty in class URLConnection

Parameters:

value - the value to be set

key - the keyword by which the request is known (e.g., "Accept").

See Also:

URLConnection.getRequestProperty(java.lang.String)

streaming

public boolean streaming()

usingProxy

public boolean usingProxy()

Description copied from class: HttpURLConnection

Indicates if the connection is going through a proxy.

Specified by:

usingProxy in class HttpURLConnection

Returns:

a boolean indicating if the connection is using a proxy.