URL URL(String, String, int, String) in Java

URL(String, String, int, String): This method is available in the java.net.URL class of Java.

Syntax:

java.net.URL.URL(String protocol, String host, int port, String file) throws MalformedURLException

This method takes four arguments. This method creates a URL object from the specified protocol, host, port number, and file. host can be expressed as a hostname or a literal IP address.

If IPv6 literal address is used, it should be closed in square brackets ('[' and ']'), as specified by RFC 2732; However, the literal IPv6 address format defined in RFC 2373: IPVersion 6 Addressing Architecture is also accepted.

Specifying a port number of -1 indicates that the URL should use the default port for the protocol.

Parameters: Four parameters are required for this method.

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.

Throws:

1. MalformedURLException - if an unknown protocol or the port is a negative number other than -1.

Approach 1: When no exception

Java

package com.URL;

import java.net.MalformedURLException;
import java.net.URL;

public class URL5 {
    public static void main(String[] args) throws MalformedURLException {

        String protocol = "http", host = "localhost", file = "/hello";
        int port = 8089;
        URL url = new URL(protocol, host, port, file);

        System.out.println(url);
    }
}

Output:

http://localhost:8089/hello

Approach 2: MalformedURLException

Java

package com.URL;

import java.net.MalformedURLException;
import java.net.URL;

public class URL5 {
    public static void main(String[] args) throws MalformedURLException {

        String protocol = "", host = "localhost", file = "/hello";
        int port = 8089;
        URL url = new URL(protocol, host, port, file);

        System.out.println(url);
    }
}

Output:

Exception in thread "main" java.net.MalformedURLException: unknown protocol: 
	at java.base/java.net.URL.<init>(URL.java:479)
	at java.base/java.net.URL.<init>(URL.java:365)
	at com.URL.URL5.main(URL5.java:11)

Some other methods of the URL class

URL(String): This method creates a URL object from the String representation.

URL(URL, String): This method creates a URL by parsing the given spec within a specified context.

URL(String, String, String): This method creates a URL from the specified protocol name, hostname, and file name.

URL(URL, String, URLStreamHandler): This method creates a URL by parsing the given spec with the specified handler within a specified context.

URL(String, String, int, String): This method creates a URL object from the specified protocol, host, port number, and file. host can be expressed as a hostname or a literal IP address.

URL(String, String, int, String, URLStreamHandler): This method creates a URL object from the specified protocol, host, port number, file, and handler.

equals(Object): This method compares this URL for equality with another object.

getAuthority(): This method gets the authority part of this URL.

getContent(): This method gets the contents of this URL.

getContent(Class<?>[]): This method gets the contents of this URL.

getDefaultPort(): This method gets the default port number of the protocol associated with this URL.

getFile(): This method gets the file name of this URL. 

getHost(): This method gets the hostname of this URL, if applicable.

getPath(): This method gets the path part of this URL.

getPort(): This method gets the port number of this URL.

getProtocol(): This method gets the protocol name of this URL.

getQuery(): This method gets the query part of this URL.

getRef(): This method gets the anchor (also known as the "reference") of this URL.

getUserInfo(): This method gets the userInfo part of this URL.

hashCode(): This method creates an integer suitable for hash table indexing.

openConnection(): This method returns a URLConnection instance that represents a connection to the remote object referred to by the URL.

openConnection(Proxy): This method returns a URLConnection instance that represents a connection to the remote object referred to by the URL with Proxy.

openStream(): This method opens a connection to this URL and returns an InputStream for reading from that connection.

sameFile(URL): This method compares two URLs, excluding the fragment component.

URL.setURLStreamHandlerFactory(URLStreamHandlerFactory): This method sets an application's URLStreamHandlerFactory.This method can be called at most once in a given Java VirtualMachine.

toExternalForm(): This method constructs a string representation of this URL. 

toString(): This method constructs a string representation of this URL. The string is created by calling the toExternalForm method of the stream protocol handler for this object.

toURI(): This method returns a java.net.URI equivalent to this URL.