URL URL(URL, String, URLStreamHandler) in Java

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

Syntax:

java.net.URL.URL(URL context, String spec, URLStreamHandler handler) throws MalformedURLException

This method takes three arguments. This method creates a URL by parsing the given spec with the specified handler within a specified context. If the handler is null, the parsing occurs as with the two-argument constructor.

Parameters: Three parameters are required for this method.

context: the context in which to parse the specification.

spec: the String to parse as a URL.

handler: the stream handler for the URL.

Throws:

1. MalformedURLException - if no protocol is specified, or an unknown protocol is found, or spec is null, or the parsed URL fails to comply with the specific syntax of the associated protocol.

2. SecurityException - if a security manager exists and its checkPermission method doesn't allow specifying a stream handler.

Approach 1: When no exception

Java

package com.URL;

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;

public class URL4 {
    public static void main(String[] args) throws MalformedURLException {

        String spec = "http://localhost:8080/hello";
        URL context = new URL(spec);
        URLStreamHandler handler = new URLStreamHandler() {

            @Override
            protected URLConnection openConnection(URL u) throws IOException {
                URL url = new URL("http://googel.com/");
                URLConnection urlcon = url.openConnection();
                return urlcon;
            }
        };
        URL url = new URL(context, spec, handler);

        System.out.println(url);
    }
}

Output:

http://localhost:8080/hello

Approach 2: MalformedURLException

Java

package com.URL;

import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLConnection;
import java.net.URLStreamHandler;

public class URL4 {
    public static void main(String[] args) throws MalformedURLException {

        String spec = "://localhost:8080/hello";
        URL context = new URL(spec);
        URLStreamHandler handler = new URLStreamHandler() {

            @Override
            protected URLConnection openConnection(URL u) throws IOException {
                URL url = new URL("http://googel.com/");
                URLConnection urlcon = url.openConnection();
                return urlcon;
            }
        };
        URL url = new URL(context, spec, handler);

        System.out.println(url);
    }
}

Output:

Exception in thread "main" java.net.MalformedURLException: no protocol: ://localhost:8080/hello
	at java.base/java.net.URL.<init>(URL.java:672)
	at java.base/java.net.URL.<init>(URL.java:568)
	at java.base/java.net.URL.<init>(URL.java:515)
	at com.URL.URL4.main(URL4.java:13)

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.