Java Tips .....

To get directory names inside a particular directory ....

private String[] getDirectoryNames(String path) {

        File fileName = new File(path);
        String[] directoryNamesArr = fileName.list(new FilenameFilter() {
            @Override
            public boolean accept(File current, String name) {
                return new File(current, name).isDirectory();
            }
        });
        log.info("Directories inside " + path + " are " + Arrays.toString(directoryNamesArr));
        return directoryNamesArr;
    }


To retrieve links on a web page ......

 private List<String> getLinks(String url) throws ParserException {
        Parser htmlParser = new Parser(url);
        List<String> links = new LinkedList<String>();

        NodeList tagNodeList = htmlParser.extractAllNodesThatMatch(new NodeClassFilter(LinkTag.class));
        for (int x = 0; x < tagNodeList.size(); x++) {
            LinkTag loopLinks = (LinkTag) tagNodeList.elementAt(m);
            String linkName = loopLinks.getLink();
            links.add(linkName);
        }
        return links;
    }


To search for all files in a directory recursively from the file/s extension/s ......

private List<String> getFilesWithSpecificExtensions(String filePath) throws ParserException {

// extension list - Do not specify "." 
 List<File> files = (List<File>) FileUtils.listFiles(new File(filePath),
                new String[]{"txt"}, true);

        File[] extensionFiles = new File[files.size()];

        Iterator<File> itFileList = files.iterator();
        int count = 0;

        while (itFileList.hasNext()) {
            File filePath = itFileList.next();
            extensionFiles[count] = filePath;
            count++;
        }
        return extensionFiles;
} 

Reading files in a zip

     public static void main(String[] args) throws IOException {
        final ZipFile file = new ZipFile("Your zip file path goes here");
        try
        {
            final Enumeration<? extends ZipEntry> entries = file.entries();
            while (entries.hasMoreElements())
            {
                final ZipEntry entry = entries.nextElement();
                System.out.println( "Entry "+ entry.getName() );
                readInputStream( file.getInputStream( entry ) );
            }
        }
        finally
        {
            file.close();
        }
    }
        private static int readInputStream( final InputStream is ) throws IOException {
            final byte[] buf = new byte[8192];
            int read = 0;
            int cntRead;
            while ((cntRead = is.read(buf, 0, buf.length) ) >=0)
            {
                read += cntRead;
            }
            return read;
        } 


Converting Object A to Long[]

 long [] myLongArray = (long[])oo;
        Long myLongArray [] = new Long[myLongArray.length];
        int i=0;

        for(long temp:myLongArray){
            myLongArray[i++] = temp;
        } 

Getting cookie details on HTTP clients

import org.apache.http.impl.client.DefaultHttpClient;

HttpClient httpClient = new DefaultHttpClient();

((DefaultHttpClient) httpClient).getCookieStore().getCookies(); 

 HttpPost post = new HttpPost(URL);
        post.setHeader("User-Agent", USER_AGENT);
        post.addHeader("Referer",URL );
        List<NameValuePair> urlParameters = new ArrayList<NameValuePair>();
        urlParameters.add(new BasicNameValuePair("username", "admin"));
        urlParameters.add(new BasicNameValuePair("password", "admin"));
        urlParameters.add(new BasicNameValuePair("sessionDataKey", sessionKey));
        post.setEntity(new UrlEncodedFormEntity(urlParameters));
        return httpClient.execute(post);


Ubuntu Commands

1. Getting the process listening to a given port (eg: port 9000) 

sudo netstat -tapen | grep ":9000 "


Running  a bash script from python script

shell.py
-----------

import os

def main():

    os.system("sh hello.sh")

if __name__=="__main__":
 os.system("sh hello.sh")


hello.sh
-----------
#Linux shell Script


echo "Hello Python from Shell";

public void scriptExecutor() throws IOException {

    log.info("Start executing the script to trigger the docker build ... ");

    Process p = Runtime.getRuntime().exec(
            "python  /home/dimuthu/Desktop/Python/shell.py ");
    BufferedReader in = new BufferedReader(new InputStreamReader(
            p.getInputStream()));
    log.info(in.readLine());

    log.info("Finished executing the script to trigger the docker build ... ");

}