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

Creates a URL object from the specified protocol, host, port number, and file.

host can be expressed as a host name or a literal IP address. If IPv6 literal address is used, it should be enclosed in square brackets ('[' and ']'), as specified by RFC 2732; However, the literal IPv6 address format defined in RFC 2373: IP Version 6 Addressing Architecture is also accepted.

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:

1. 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.
2. 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:

            java.protocol.handler.pkgs
        

   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.
3. If the previous step fails to find a protocol handler, then the constructor tries to load from a system default package.

            <system default package>.<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.

Protocol handlers for the following protocols are guaranteed to exist on the search path :-

     http, https, ftp, file, and jar
 

Protocol handlers for additional protocols may also be available.

No validation of the inputs is performed by this constructor.

Parameters:

protocol		the name of the protocol to use.
host		the name of the host.
port		the port number on the host.
file		the file on the host

Exceptions:

MalformedURLException

if an unknown protocol is specified.

See also:
java.lang.System.getProperty(java.lang.String), java.net.URL.setURLStreamHandlerFactory( java.net.URLStreamHandlerFactory), java.net.URLStreamHandler, java.net.URLStreamHandlerFactory.createURLStreamHandler( java.lang.String)