Thursday, January 11, 2018

function to print the repeated values in an array with it's count

public static void printRepeating(int arr[], int size)
{
int i,j;
System.out.println("The repeating elements are : ");
HashMap<Integer, Integer> hmap = new HashMap<>();

for (i = 0; i < size-1; i++)
{
int c=1;
for (j = i+1; j < size; j++)
{

if(arr[i]==arr[j]){
c++;
}
}
if(c>1&& !hmap.containsValue(arr[i])){

hmap.put(c,arr[i]);

}
}

for (int k:hmap.keySet()){
System.out.println(hmap.get(k)+" : count "+k);
}
}


Sunday, January 7, 2018

java program to download file from url


import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.URL;

public class URLReader {

    public static void copyURLToFile(URL url, File file) {

        try {
            InputStream input = url.openStream();
            if (file.exists()) {
                if (file.isDirectory())
                    throw new IOException("File '" + file + "' is a directory");

                if (!file.canWrite())
                    throw new IOException("File '" + file + "' cannot be written");
            } else {
                File parent = file.getParentFile();
                if ((parent != null) && (!parent.exists()) && (!parent.mkdirs())) {
                    throw new IOException("File '" + file + "' could not be created");
                }
            }

            FileOutputStream output = new FileOutputStream(file);

            byte[] buffer = new byte[4096];
            int n = 0;
            while (-1 != (n = input.read(buffer))) {
                output.write(buffer, 0, n);
            }

            input.close();
            output.close();

            System.out.println("File '" + file + "' downloaded successfully!");
        }
        catch(IOException ioEx) {
            ioEx.printStackTrace();
        }
    }

    public static void main(String[] args) throws IOException {

        //URL pointing to the file
        String sUrl = "https://singztechmusings.files.wordpress.com/2011/09/maven_eclipse_and_osgi_working_together.pdf";

        URL url = new URL(sUrl);

        //File where to be downloaded
        File file = new File("home\\sujith\\IdeaProjects\\downloadTest");

        URLReader.copyURLToFile(url, file);
    }

}

java program to download a file from an external url

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.net.MalformedURLException;
import java.net.URL;
import org.apache.commons.io.FileUtils;
public class FileDownloadTest {
public static void main(String[] args) {
try {
// Make sure that this directory exists
String dirName = "home\\sujith\\FileDownload";
System.out.println("Downloading \'Maven, Eclipse and OSGi working together\' PDF document...");
saveFileFromUrlWithJavaIO(
dirName + "\\maven_eclipse_and_osgi_working_together.pdf",
"https://singztechmusings.files.wordpress.com/2011/09/maven_eclipse_and_osgi_working_together.pdf");
System.out.println("Downloaded \'Maven, Eclipse and OSGi working together\' PDF document.");
System.out.println("Downloading \'InnoQ Web Services Standards Poster\' PDF document...");
saveFileFromUrlWithCommonsIO(
dirName + "\\innoq_ws-standards_poster_2007-02.pdf",
"http://singztechmusings.files.wordpress.com/2011/08/innoq_ws-standards_poster_2007-02.pdf");
System.out.println("Downloaded \'InnoQ Web Services Standards Poster\' PDF document.");
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
// Using Java IO
public static void saveFileFromUrlWithJavaIO(String fileName, String fileUrl)
throws MalformedURLException, IOException {
BufferedInputStream in = null;
FileOutputStream fout = null;
try {
in = new BufferedInputStream(new URL(fileUrl).openStream());
fout = new FileOutputStream(fileName);
byte data[] = new byte[1024];
int count;
while ((count = in.read(data, 0, 1024)) != -1) {
fout.write(data, 0, count);
}
} finally {
if (in != null)
in.close();
if (fout != null)
fout.close();
}
}
// Using Commons IO library
// Available at http://commons.apache.org/io/download_io.cgi
public static void saveFileFromUrlWithCommonsIO(String fileName,
String fileUrl) throws MalformedURLException, IOException {
FileUtils.copyURLToFile(new URL(fileUrl), new File(fileName));
}
}

//https://mvnrepository.com/artifact/commons-io/commons-io/2.4