Class java.net.URL

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Class java.net.URL

java.lang.Object
|
   +----java.net.URL

public final class URL
extends Object

Class URL represents a Uniform Reference Locator -- a reference to an object on the World Wide Web. This is a constant object, once it is created, its fields cannot be changed.

URL(String): Creates a URL from the unparsed absolute URL.
URL(String, String, int, String): Creates an absolute URL from the specified protocol, host, port and file.
URL(String, String, String): Creates an absolute URL from the specified protocol, host, and file.
URL(URL, String): Creates a URL from the unparsed URL in the specified context.If spec is an absolute URL it is used as is.

equals(Object): Compares two URLs.
getContent(): Gets the contents from this opened connection.
getFile(): Gets the file name.
getHost(): Gets the host name.
getPort(): Gets the port number.
getProtocol(): Gets the protocol name.
getRef(): Gets the ref.
hashCode(): Creates an integer suitable for hash table indexing.
openConnection(): Creates (if not already in existance) a URLConnection object that contains a connection to the remote object referred to by the URL.
openStream(): Opens an input stream.
sameFile(URL): Compares two URLs, excluding the "ref" fields: sameFile is true if the true references the same remote object, but not necessarily the same subpiece of that object.
set(String, String, int, String, String): Sets the fields of the URL.
setURLStreamHandlerFactory(URLStreamHandlerFactory): Sets the URLStreamHandler factory.
toExternalForm(): Reverses the parsing of the URL.
toString(): Converts to a human-readable form.

URL

public URL(String protocol,
String host,
             int port,
String file) throws MalformedURLException

Creates an absolute URL from the specified protocol, host, port and file.

Parameters:: protocol - the protocol to use; host - the host to connect to; port - the port at that host to connect to; file - the file on that host
Throws: MalformedURLException: If an unknown protocol is found.

URL

public URL(String protocol,
String host,
String file) throws MalformedURLException

Creates an absolute URL from the specified protocol, host, and file. The port number used will be the default for the protocol.

Parameters:: protocol - the protocol to use; host - the host to connect to; file - the file on that host
Throws: MalformedURLException: If an unknown protocol is found.

URL

public URL(String spec) throws MalformedURLException

Creates a URL from the unparsed absolute URL.

Parameters:: spec - the URL String to parse

URL

public URL(URL context,
String spec) throws MalformedURLException

Creates a URL from the unparsed URL in the specified context.If spec is an absolute URL it is used as is. Otherwise it isparsed in terms of the context. Context may be null (indicating no context).

Parameters:: context - the context to parse the URL to; spec - the URL String to parse
Throws: MalformedURLException: If the protocol is equal to null.

set

protected void set(String protocol,
String host,
                     int port,
String file,
String ref)

Sets the fields of the URL. This is not a public method so that only URLStreamHandlers can modify URL fields. URLs are otherwise constant. REMIND: this method will be moved to URLStreamHandler

Parameters:: protocol - the protocol to use; host - the host name to connecto to; port - the protocol port to connect to; file - the specified file name on that host; ref - the reference

getPort

public int getPort()

Gets the port number. Returns -1 if the port is not set.

getProtocol

public String getProtocol()

Gets the protocol name.

getHost

public String getHost()

Gets the host name.

getFile

public String getFile()

Gets the file name.

getRef

public String getRef()

Gets the ref.

equals

public boolean equals(Object obj)

Compares two URLs.

Parameters:: obj - the URL to compare against.
Returns:: true if and only if they are equal, false otherwise.
Overrides:: equals in class Object

hashCode

public int hashCode()

Creates an integer suitable for hash table indexing.

Overrides:: hashCode in class Object

sameFile

public boolean sameFile(URL other)

Compares two URLs, excluding the "ref" fields: sameFile is true if the true references the same remote object, but not necessarily the same subpiece of that object.

Parameters:: other - the URL to compare against.
Returns:: true if and only if they are equal, false otherwise.

toString

public String toString()

Converts to a human-readable form.

Returns:: the textual representation.
Overrides:: toString in class Object

toExternalForm

public String toExternalForm()

Reverses the parsing of the URL.

Returns:: the textual representation of the fully qualified URL (i.e. after the context and canonicalization have been applied).

openConnection

public URLConnection openConnection() throws IOException

Creates (if not already in existance) a URLConnection object that contains a connection to the remote object referred to by the URL. Invokes the appropriate protocol handler. Failure is indicated by throwing an exception.

Throws: IOException: If an I/O exception has occurred.
See Also:: URLConnection

openStream

public final InputStream openStream() throws IOException

Opens an input stream.

Throws: IOException: If an I/O exception has occurred.

getContent

public final Object getContent() throws IOException

Gets the contents from this opened connection.

Throws: IOException: If an I/O exception has occurred.

setURLStreamHandlerFactory

public static synchronized void setURLStreamHandlerFactory(URLStreamHandlerFactory fac)

Sets the URLStreamHandler factory.

Parameters:: fac - the desired factory
Throws: Error: If the factory has already been defined.

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