AvailableJDK.java Can you please help me write the JAVA program to query http://

Question

AvailableJDK.java

Can you please help me write the JAVA program to query

http://www.oracle.com/technetwork/java/javase/downloads/index.html

and display the first release number for a JDK listed on that page (and ONLY the release number). For example, at the time of this writing, the output would be

8u101

This summer (when our virtual machines were created), the release number output would have been

8u91

Your program should handle any thrown exceptions with an informative message.

===============

Example program:

HtmlReader.java

import javax.naming.MalformedLinkException;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.Scanner;

public class HtmlReader {

public static void main(String[] args) {
String urlName = null;

if (args.length != 1) {
System.out
.println("Must have exactly 1 command line parameter that is a URL");
System.exit(4);
}

urlName = args[0];
Scanner scan = null;

URL webPage = null;
try {
webPage = new URL(urlName);
scan = new Scanner(webPage.openStream());
while (scan.hasNextLine()) {
System.out.println(scan.nextLine());
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (scan != null) scan.close();
scan = null;
}
/*
       Create a URL object based on urlName (done--see above)

       URL objects have an openStream() method that opens a connection
       across a network and allows us to read whatever's at that specific location.
       It returns an object of type InputStream

       A Scanner can be created based on an InputStream object.

       Once you have a Scanner object, use a while loop and hasNextLine and nextLine
       to read the web page.
       Use System.out.println to print each line

       Use try/catch/finally to handle exceptions

       Close the Scanner in the finally block
       */

}

}

Explanation / Answer

PROGRAM CODE:

package sample;

import javax.naming.MalformedLinkException;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.IOException;

import java.net.MalformedURLException;

import java.net.URL;

import java.util.Scanner;

public class HtmlReader {

public static void main(String[] args) {

String urlName = null;

if (args.length != 1) {

System.out

.println("Must have exactly 1 command line parameter that is a URL");

System.exit(4);

}

urlName = args[0];

Scanner scan = null;

URL webPage = null;

try {

webPage = new URL(urlName);

scan = new Scanner(webPage.openStream());

int i = 0;

while (scan.hasNextLine()) {

   String line = scan.nextLine();

   if(line.contains("Java Platform (JDK) "))

   {

       int index = line.indexOf("Java Platform (JDK) ");

       line = line.substring(index, index+26);

       line = line.replace("Java Platform (JDK) ", "");

       System.out.println(line);

   }

}

}

catch(FileNotFoundException e)

{

   System.out.println("The mentioned URL was not found !");

}

catch (MalformedURLException e) {

e.printStackTrace();

} catch (IOException e) {

e.printStackTrace();

} finally {

if (scan != null) scan.close();

scan = null;

}

/*

Create a URL object based on urlName (done--see above)

URL objects have an openStream() method that opens a connection

across a network and allows us to read whatever's at that specific location.

It returns an object of type InputStream

A Scanner can be created based on an InputStream object.

Once you have a Scanner object, use a while loop and hasNextLine and nextLine

to read the web page.

Use System.out.println to print each line

Use try/catch/finally to handle exceptions

Close the Scanner in the finally block

   */

}

}

OUTPUT:
8u111

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