URL.URL
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public URL( String protocol,
String host,
int port,
String file ) throws MalformedURLException
Parameters
- protocol
- the name of the protocol.
- host
- the name of the host.
- port
- the port number.
- file
- the host file.
Description
Creates a URL object from the specified
protocol, host, port
number, and file. Specifying a port
number of -1 indicates that the URL should use
the default port for the protocol.
If this is the first URL object being created with the specified
protocol, a stream protocol handler object, an instance of
class URLStreamHandler, is created for that protocol:
- If the application has previously set up an instance of
URLStreamHandlerFactory as the stream handler factory,
then the createURLStreamHandler method of that instance
is called with the protocol string as an argument to create the
stream protocol handler.
- If no URLStreamHandlerFactory has yet been set up,
or if the factory's createURLStreamHandler method
returns null, then the constructor finds the
value of the system property:
If the value of that system property is not null,
it is interpreted as a list of packages separated by a vertical
slash character '|'. The constructor tries to load
the class named:
<package>.<protocol>.Handler
where <package> is replaced by the name of the package
and <protocol> is replaced by the name of the protocol.
If this class does not exist, or if the class exists but it is not
a subclass of URLStreamHandler, then the next package
in the list is tried.
- If the previous step fails to find a protocol handler, then the
constructor tries to load the class named:
sun.net.www.protocol.<protocol>.Handler
If this class does not exist, or if the class exists but it is not a
subclass of URLStreamHandler, then a
MalformedURLException is thrown.
Exceptions
MalformedURLException
if an unknown protocol is specified.
See Also
getProperty, setURLStreamHandlerFactory, URLStreamHandler, createURLStreamHandler
public URL( String protocol,
String host,
String file ) throws MalformedURLException
Parameters
- protocol
- the protocol to use.
- host
- the host to connect to.
- file
- the file on that host.
Description
Creates an absolute URL from the specified protocol
name, host name, and file name. The
default port for the specified protocol is used.
This method is equivalent to calling the four-argument
constructor with the arguments being protocol,
host, -1, and file.
Exceptions
MalformedURLException
if an unknown protocol is specified.
See Also
URL
public URL( String spec ) throws MalformedURLException
Parameters
- spec
- the String to parse as a URL.
Description
Creates a URL object from the String
representation.
This constructor is equivalent to a call to the two-argument
constructor with a null first argument.
Exceptions
MalformedURLException
If the string specifies an
unknown protocol.
See Also
URL
public URL( URL context,
String spec ) throws MalformedURLException
Parameters
- context
- the context in which to parse the specification.
- spec
- a String representation of a URL.
Description
Creates a URL by parsing the specification spec
within a specified context. If the context argument
is not null and the spec argument is a
partial URL specification, then any of the strings missing
components are inherited from the context argument.
The specification given by the String argument is
parsed to determine if it specifies a protocol. If the
String contains an ASCII colon ':'
character before the first occurrence of an ASCII slash character
'/', then the characters before the colon comprise
the protocol.
- If the spec argument does not specify a protocol:
- If the context argument is not null, then the
protocol is copied from the context argument.
- If the context argument is null, then a
MalformedURLException is thrown.
- If the spec argument does specify a protocol:
- If the context argument is null, or specifies a
different protocol than the specification argument, the context
argument is ignored.
- If the context argument is not null and specifies
the same protocol as the specification, the host,
port number, and file are copied from
the context argument into the newly created URL.
The constructor then searches for an appropriate stream protocol
handler of type URLStreamHandler as outlined for:
java.net.URL#URL(java.lang.String, java.lang.String, int,
java.lang.String)
The stream protocol handler's
parseURL method is called to parse the remaining
fields of the specification that override any defaults set by the
context argument.
Exceptions
MalformedURLException
if no protocol is specified, or an
unknown protocol is found.
See Also
URL, URLStreamHandler, parseURL