Parse XML file using DOM

This code snippet explains about the parsing of the xml file using the DOM parser.

import java.io.File;
import java.io.IOException;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;


public class XMLParser {

    /**
     * @param args
     * @throws IOException 
     * @throws SAXException 
     */
    
    public void GetXMLValue(String FileName){
    
        try {
            DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
            DocumentBuilder db         = dbf.newDocumentBuilder();
            File file                  = new File(FileName);
            
            if(file.exists()){
                Document doc = null;
                try {
                    doc = db.parse(file);
                }
                catch (SAXException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                Element docelement1     = doc.getDocumentElement();
                
                System.out.println("Root element of the document: "
                        + docelement1.getNodeName());                
                //for commercial credit
                NodeList valueList1 = docelement1.getElementsByTagName("CommercialCredit");
                
                if (valueList1 != null && valueList1.getLength() > 0) {
                 
                    for (int i = 0; i < valueList1.getLength(); i++) {
                        
                        Node node = valueList1.item(i);
                        
                        if (node.getNodeType() == Node.ELEMENT_NODE) {
                            
                            Element e = (Element) node;
                            NodeList nodeList = e.getElementsByTagName("DistSourceId");
                            System.out.println("DistSourceId: "
                                    + nodeList.item(0).getChildNodes().item(0)
                                            .getNodeValue());

                            nodeList = e.getElementsByTagName("MMSReferenceStartTime");
                            System.out.println("MMSReferenceStartTime: "
                                    + nodeList.item(0).getChildNodes().item(0)
                                            .getNodeValue());

                            nodeList = e.getElementsByTagName("MMSReferenceEndTime");
                            System.out.println("MMSReferenceEndTime: "
                                    + nodeList.item(0).getChildNodes().item(0)
                                            .getNodeValue());  
                        }                        
                     // for Credit result ---- added only 3 fields to test.....                        
                        
                        NodeList valueList2 = docelement1.getElementsByTagName("CreditResult");
                        if (valueList2 != null && valueList2.getLength() > 0) {
                            
                            for (int j = 0; j < valueList2.getLength(); j++) {
                                
                                Element e2 = (Element) node;
                                NodeList nodeList2 = e2.getElementsByTagName("MediaAssetId");
                                System.out.println("MediaAssetId: "
                                        + nodeList2.item(0).getChildNodes().item(0)
                                                .getNodeValue());
                                
                                nodeList2 = e2.getElementsByTagName("DetectedTime");
                                System.out.println("DetectedTime: "
                                        + nodeList2.item(0).getChildNodes().item(0)
                                                .getNodeValue());
                                
                                nodeList2 = e2.getElementsByTagName("DetectedSourceId");
                                System.out.println("DetectedSourceId: "
                                        + nodeList2.item(0).getChildNodes().item(0)
                                                .getNodeValue());  
                            }
                        }//if ends here
                    }  
                }
                else{
                    System.exit(1);
                }                    
            }
        }
        catch (ParserConfigurationException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }         
    }    
    
    public static void main (String[] args) throws SAXException, IOException {
        // TODO Auto-generated method stub
        String str = "C:\Test\Mytestfile.xml";
        new XMLParser().GetXMLValue(str);

    }

}

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Listing Files and Directory Using Java

Lists Files and directory present in the system   

File dir = new File("directoryName"); 
 String[] children = dir.list();
  if (children == null) 
{      
// Either dir does not exist or is not a directory 
 }
 else 
{   
   for (int i=0; i < children.length; i++) 
{
          // Get filename of file or directory       
   String filename = children[i];     
 }
  }
   // It is also possible to filter the list of returned files.
  // This example does not return any files that start with `.'.  
FilenameFilter filter = new FilenameFilter() 
{      
public boolean accept(File dir, String name)
 {
          return !name.startsWith(".");    
  }
  };
  children = dir.list(filter);
   // The list of files can also be retrieved as File 
File[] files = dir.listFiles();   
// This filter only returns directories  
FileFilter fileFilter = new FileFilter()
 {

      public boolean accept(File file)
 {
          return file.isDirectory();   
   }
  };  
files = dir.listFiles(fileFilter); 

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To Capture screen shots using Java

import java.awt.Dimension;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.image.BufferedImage;
import javax.imageio.ImageIO;
import java.io.File;
public void captureScreen(String fileName) throws Exception 
{
    Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();   
Rectangle screenRectangle = new Rectangle(screenSize);  
 Robot robot = new Robot();  
 BufferedImage image = robot.createScreenCapture(screenRectangle);  
 ImageIO.write(image, "png", new File(fileName)); 
}

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Extract a zip file in Java

The sole purpose of this program is how to extarct the content of a zip file in java.We start by opening an input stream to the compressed file and an output stream to the file where we want the content to be extracted.

After that we get the next entry of the zip file (and the only entry in this case) - test so it's not null, and then start reading the contents from the input stream and writing each chunk read to the output stream.

As usual we should clean up properly afterwards so we close the input and output streams.

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.zip.ZipEntry;
import java.util.zip.ZipInputStream;

public class ExtractingZipFile{

    /**
     * Extracts a zip file
     */
    public void extractZipFile() {
        
        try {
            String zipFileName = "file.zip";
            String extractedFileName = "extractedfile.txt";
            
            //Create input and output streams
            ZipInputStream inStream = new ZipInputStream(new FileInputStream(zipFileName));
            OutputStream outStream = new FileOutputStream(extractedFileName);
            
            ZipEntry entry;
            byte[] buffer = new byte[1024];
            int nrBytesRead;
            
            //Get next zip entry and start reading data
            if ((entry = inStream.getNextEntry()) != null) {
                while ((nrBytesRead = inStream.read(buffer)) > 0) {
                    outStream.write(buffer, 0, nrBytesRead);
                }
            }
                    
            //Finish off by closing the streams
            outStream.close();
            inStream.close();
            
        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
    
    
    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        new ExtractingZipFile().extractZipFile();
    }
    
}

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Albers Square using JAVA

Albers Square using JAVA

public class AlbersSquares {

    public static void main(String[] args) {

        StdDraw.setCanvasSize(800, 800);

        // first color
        int r1 = Integer.parseInt(args[0]);
        int g1 = Integer.parseInt(args[1]);
        int b1 = Integer.parseInt(args[2]);
        Color c1 = new Color(r1, g1, b1);

        // second color
        int r2 = Integer.parseInt(args[3]);
        int g2 = Integer.parseInt(args[4]);
        int b2 = Integer.parseInt(args[5]);
        Color c2 = new Color(r2, g2, b2);

        // first Albers square
        StdDraw.setPenColor(c1);
        StdDraw.filledSquare(.25, .5, .2);
        StdDraw.setPenColor(c2);
        StdDraw.filledSquare(.25, .5, .1);

        // second Albers square
        StdDraw.setPenColor(c2);
        StdDraw.filledSquare(.75, .5, .2);
        StdDraw.setPenColor(c1);
        StdDraw.filledSquare(.75, .5, .1);
    } 
} 

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Doubling Stack of Strings using Java

Doubling Stack of Strings using Java  

import java.util.Iterator;
import java.util.NoSuchElementException;

public class DoublingStackOfStrings implements Iterable<String> {
    private String[] a;
    private int N;

    public DoublingStackOfStrings() {
        a = new String[2];
        N = 0;
    }

    // is the stack empty?
    public boolean isEmpty() {  return (N == 0);  }

    // resize the underlying array holding the elements
    private void resize(int capacity) {
        String[] temp = new String[capacity];
        for (int i = 0; i < N; i++) {
            temp[i] = a[i];
        }
        a = temp;
    }

    // push a new item onto the stack
    public void push(String item) {
        if (N == a.length) resize(2*a.length);
        a[N++] = item;
    }

    // delete and return the item most recently added
    public String pop() {
        if (isEmpty()) { throw new RuntimeException("Stack underflow error"); }
        String item = a[--N];
        a[N] = null;  // to avoid loitering
        if (N > 0 && N == a.length/4) resize(a.length/2);
        return item;
    }

    public Iterator<String> iterator()  { return new ReverseArrayIterator();  }

    // an iterator, doesn't implement remove() since it's optional
    private class ReverseArrayIterator implements Iterator<String> {
        private int i = N;
        public boolean hasNext()  { return i > 0;                               }
        public void remove()      { throw new UnsupportedOperationException();  }

        public String next() {
            if (!hasNext()) throw new NoSuchElementException();
            return a[--i];
        }
    }

    // test client
    public static void main(String[] args) {
        DoublingStackOfStrings s = new DoublingStackOfStrings();
        while (!StdIn.isEmpty()) {
            String item = StdIn.readString();
            if (!item.equals("-")) s.push(item);
            else if (s.isEmpty())  StdOut.println("BAD INPUT");
            else                   StdOut.print(s.pop());
        }
    }

}

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Excel Comparator xls or xlsx in java

we can compare any two excels of extension either xls or xlsx   

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFRow;
import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
public class Excelcomparison {
 ArrayList<String> listOfTerms =null;
 ArrayList<String> al =new ArrayList<String>();
 ArrayList<String> finallist = new ArrayList<String>();
 public  Workbook checkFileFormat(String fileName){
  Workbook hwb=null;
  
  FileInputStream checkFis=null;
  try{
    checkFis=new FileInputStream(fileName);
    //Instantiate the Workbook using HSSFWorkbook
    hwb=(Workbook)new HSSFWorkbook(checkFis);
    Sheet sheet=hwb.getSheetAt(0);
    Iterator<Row> rows=sheet.rowIterator();
   
    Iterator<Cell> cells=null;
    Row row=null;
    Cell cell=null;
    int check=0;
    //Read the file as HSSFWorkbook
    while(rows.hasNext()){
    check++;
    row=(HSSFRow)rows.next();
    cells=row.cellIterator();
    while(cells.hasNext()){
     cell=(HSSFCell)cells.next();
    }
    if(check==2)
     break;
   }
   //Return HSSFWorkbook type object if there is no exception in reading the file using HSSFWorkbook
   return hwb;
  }catch(ClassCastException ce){  //Instantiate the Workbook using XSSFWorkbook in case of class cast exception
   Workbook xwb=null;
   try{
   xwb=new XSSFWorkbook(checkFis);  
   checkFis.close();
   }catch(IOException e){    
   e.printStackTrace();
     }
  return xwb; }
  catch(Exception e){ //Instantiate the Workbook using XSSFWorkbook in case of Exception while reading file through HSSFWorkbook
  Workbook xwb=null;
  try{
   if(checkFis!=null)
  checkFis.close();
  checkFis=null;
  checkFis=new FileInputStream(fileName);
  xwb=new XSSFWorkbook(checkFis); 
  checkFis.close();
  }catch(Exception ie){
   
 return null;
  }
  
 return xwb;
 }
 }
 public void readExcel()
 {
  try
  {
   Workbook workbook = checkFileFormat("EXCEL1.xlsx");
  listOfTerms =new ArrayList<String>();
  Sheet sheet = workbook.getSheetAt(0);
  int rows  = sheet.getPhysicalNumberOfRows();
  System.out.println("here "+rows+"   "+sheet.getSheetName());
  for (int r = 0; r < rows; r++)
  {
       Row row   = sheet.getRow(r);
       Cell cell =row.getCell((short)0);
       String cellValue = cell.getStringCellValue().trim();
       listOfTerms.add(cellValue);
    }
      System.out.println(listOfTerms);
      Workbook workbook1 = checkFileFormat("EXCEL2.xls");
      Sheet sheet1 = workbook1.getSheetAt(0);
      int rows1  = sheet1.getPhysicalNumberOfRows();
      System.out.println("here "+rows1+"   "+sheet.getSheetName());
      for (int k = 0; k < rows1; k++)
      {
         Row row1   = sheet.getRow(k);
        Cell cell =row1.getCell((short)0);
         String cellValue2 = cell.getStringCellValue();
         al.add(cellValue2);
       
      }
        System.out.println(al);
        for(int i=0; i<al.size(); i++)
        {
        
          if(!listOfTerms.contains(al.get(i))) 
           {
             finallist.add(al.get(i));
           }
        }
        for(int i=0; i<listOfTerms.size(); i++)
        {
          if(!al.contains(listOfTerms.get(i))) 
          {
            finallist.add(listOfTerms.get(i));
          }
        }
        System.out.println("Elements which are different: " +finallist);
        System.out.println(""); 
 createSheet();
  }catch(Exception e)
  {
   e.getStackTrace();
   System.out.println(e.getMessage());
  }
 }
 private void createSheet() {
  XSSFWorkbook bookout = new XSSFWorkbook();
  try
  {
   int j=0;
   XSSFSheet sheet1= bookout.createSheet();
   bookout.setSheetName(0,"Document Handles");
    for(int m=0;m<finallist.size();m++)
    {
     XSSFRow row=sheet1.createRow(j++);
     row.createCell((short) 0).setCellValue(finallist.get(m));
     
    } 
    FileOutputStream fout = new FileOutputStream("OutputExcel.xlsx");
    bookout.write(fout);
    fout.close();
  System.out.println("file completed"); 
  }
  catch(Exception e)
  {
   System.out.println(e.getMessage());
  }
 }
  public static void main(String args[]){
  Excelcomparison e = new Excelcomparison();
  e.readExcel();
 }
}

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Code to Remove Certain Characters from a Java Input

Sometimes we can't rename a file automatically when the Filename has "/" inside them because of Windows limitations. This code might prove handy in these situations.

//Code to Remove Certain Characters from a Java Input//

try {
    String Y = X;
    String regx = "/";
    char[] ca = regx.toCharArray();
    for (char c : ca) {
     Y = Y.replace("" + c, "");
}

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Code to Populate Dropdown from a DB

Using this Java snippet the users can Populate Dropdown from a DB   

//Code to Populate Dropdown from a DB//
//In JSP//
<div id="bodydiv" align="center" >
    <select name=" Name" onchange="this.form.submit();">
     <option name="Router Name" value="0">--------select--------</option>
     <%
     GetXRouter dao = new GetXRouter();
     ArrayList ReList = dao.retreiveRname();
     for (int i = 0; i < ReList.size(); i++) {
    %>
     <option name="RName" value="<%=ReList.get(i)%>"><%=ReList.get(i)%></option>
     <%
     }
    %>
    </select>

//IN Java Class File//
public class GetList {
 static Connection conn = null;
 static Statement st = null;
 static ResultSet rs = null;
 static DBConnection db;

 
 @SuppressWarnings({ "rawtypes", "unchecked" })
 public ArrayList retreiveIname(String Rname) throws SQLException {
  Connection conn;
  DBConnection db = new DBConnection();
  conn = db.getConnection();
  Statement st;
  st = conn.createStatement();
  ResultSet rs = st.executeQuery("select tt.Y_nm from Z.Z_X_Y_cfg tt where tt.active = 'A' and tt.X_nm = '"+Rname+"' ");
  ArrayList IList = new ArrayList();
  while (rs.next()) {
   IList.add(rs.getString(1));
  }
  for (int i = 0; i < IList.size(); i++) {
   System.out.println(IList.get(i));
  }
  return IList;

 }

}

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