All about XPath

this is the sample xml.


DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
dom = db.parse("C:/templates.xml");

 XPath xpath=XPathFactory.newInstance().newXPath();
 XPathExpression expr=xpath.compile("//templates/template[1]/label/text()");
 NodeList ns=(NodeList)expr.evaluate(dom,XPathConstants.NODESET);

 for(int i=0;i    {
        System.out.println(ns.item(i).getNodeValue());
 }

here the output will be the value of the label of 1st template tag.



XPathExpression expr=xpath.compile("//templates/template/label/text()");
  NodeList ns=(NodeList)expr.evaluate(dom,XPathConstants.NODESET);

here the output will be the value of all the labels present in all the template tags


XPathExpression expr=xpath.compile("//templates/template/@name");
NodeList ns=(NodeList)expr.evaluate(dom,XPathConstants.NODESET);

here the output will be the values of attribute name of all the template tags



 XPathExpression expr=xpath.compile("//templates/template");
 NodeList ns=(NodeList)expr.evaluate(dom,XPathConstants.NODESET);
    for(int i=0;i       NamedNodeMap la=ns.item(i).getAttributes();
    System.out.println(la.getNamedItem("name").getNodeValue());
}

if a tag has more than 1 attribute, then , values of the attributes can be fetched like this.


  XPathExpression expr=xpath.compile("//templates/template/@name");
    NodeList ns=(NodeList)expr.evaluate(dom,XPathConstants.NODESET);
    for(int i=0;i         ns.item(i).setNodeValue("this is test");
         Transformer xformer = TransformerFactory.newInstance().newTransformer();
         xformer.transform(new DOMSource(dom), new StreamResult(new File("C:/templates.xml")));
    }

This code is changing the value of the specified attribute,here the attribute name is 'name' and saving in the xml

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calling procedure and functon from java code

calling stored procedure :

BufferedReader br=new BufferedReader(new InputStreamReader(System.in));


String s;
 String stmt="{call test(?)}";
 System.out.println(stmt);
 CallableStatement cs=con.prepareCall(stmt);
 System.out.println("enter the name of the employee");
 s=br.readLine();
 cs.setString(1,s);
 cs.execute();


calling function:

String stmt="{?=call test_fn(?)}";

String stmt="select test_fn('abc') from dual";
CallableStatement cs=con.prepareCall(stmt);
System.out.println("enter the name of the employee");
s=br.readLine();
cs.registerOutParameter(1,java.sql.Types.INTEGER);
cs.setString(2,s);
cs.execute();


to retrieve value
cs.getInt(1) ,so, in general , cs.get(Type)(index)


also instead of  "java.sql.Types.INTEGER", "oracle.jdbc.driver.OracleTypes.INTEGER" can be used.

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dom parser

package check;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;



public class DOM_Demo {

Document dom;

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

new DOM_Demo().go();

}


void ret(Node d){

NodeList n=d.getChildNodes();

{
System.out.println(d.getNodeName());
for@(int i=0;i{
    if(n.item(i).getNodeType()==1)  // 1 IS THE VALUE FOR TAG
{ 
ret(n.item(i));

}
else

{
if(n.item(i).getNodeValue().trim().length()!=0)
System.out.println("val : "+n.item(i).getNodeValue());
}

}


}

}

void go() throws Exception

{
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
//Using factory get an instance of document builder

DocumentBuilder db = dbf.newDocumentBuilder();
//parse using builder to get DOM representation of the XML file

dom = db.parse("C:/Users/shasharm/Desktop/ibf/NS_ABIS_IRP_IP_E1.xml");

Element d = dom.getDocumentElement();

ret(d);

}

}

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sax parser

import java.io.IOException;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;

import javax.xml.parsers.ParserConfigurationException;
import javax.xml.parsers.SAXParser;
import javax.xml.parsers.SAXParserFactory;

import org.xml.sax.Attributes;
import org.xml.sax.SAXException;

import org.xml.sax.helpers.DefaultHandler;

public class SAXParserExample extends DefaultHandler{

    List myEmpls;
   
    private String tempVal;
   
    //to maintain context
    private Employee tempEmp;
   
   
    public SAXParserExample(){
        myEmpls = new ArrayList();
    }
   
    public void runExample() {
        parseDocument();
        printData();
    }

    private void parseDocument() {
       
        //get a factory
        SAXParserFactory spf = SAXParserFactory.newInstance();
        try {
       
            //get a new instance of parser
            SAXParser sp = spf.newSAXParser();
           
            //parse the file and also register this class for call backs
            sp.parse("employees.xml", this);
           
        }catch(SAXException se) {
            se.printStackTrace();
        }catch(ParserConfigurationException pce) {
            pce.printStackTrace();
        }catch (IOException ie) {
            ie.printStackTrace();
        }
    }

    /**
     * Iterate through the list and print
     * the contents
     */
    private void printData(){
       
        System.out.println("No of Employees '" + myEmpls.size() + "'.");
       
        Iterator it = myEmpls.iterator();
        while(it.hasNext()) {
            System.out.println(it.next().toString());
        }
    }
   

    //Event Handlers
    public void startElement(String uri, String localName, String qName, Attributes attributes) throws SAXException {
        //reset
        tempVal = "";
        if(qName.equalsIgnoreCase("Employee")) {
            //create a new instance of employee
            tempEmp = new Employee();
            tempEmp.setType(attributes.getValue("type"));
        }
    }
   

    public void characters(char[] ch, int start, int length) throws SAXException {
        tempVal = new String(ch,start,length);
    }
   
    public void endElement(String uri, String localName, String qName) throws SAXException {

        if(qName.equalsIgnoreCase("Employee")) {
            //add it to the list
            myEmpls.add(tempEmp);
           
        }else if (qName.equalsIgnoreCase("Name")) {
            tempEmp.setName(tempVal);
        }else if (qName.equalsIgnoreCase("Id")) {
            tempEmp.setId(Integer.parseInt(tempVal));
        }else if (qName.equalsIgnoreCase("Age")) {
            tempEmp.setAge(Integer.parseInt(tempVal));
        }
       
    }
   
    public static void main(String[] args){
        SAXParserExample spe = new SAXParserExample();
        spe.runExample();
    }
   
}

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jdbc connection with oracle 10 g

try{


String driverName = "oracle.jdbc.driver.OracleDriver";

Class.forName(driverName);



// Create a connection to the database

String serverName = "127.0.0.1";

String portNumber = "1521";

String sid = "xe";

String url = "jdbc:oracle:thin:@" + serverName + ":" + portNumber + "/" + sid;

String username = "system";

String password = "9868626216";

Connection connection = DriverManager.getConnection(url, username, password);



String query="select * from employee";

Statement st= connection.createStatement();

ResultSet rs=st.executeQuery(query);

System.out.println(rs);

//while(rs.next())

//{



//System.out.println("not 1 empty");

//}











} catch (Exception e) {

// Could not find the database driver

e.printStackTrace();

}

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japplet fundamental

import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class test extends JApplet  {

    public void go() {
       
       
        this.setSize(500,500);
        this.setVisible(true);
   
        this.setLayout(new FlowLayout());
        System.out.println("in go");
        JButton jb=new JButton("click me");
        this.add(jb);
       jb.addActionListener(new ActionListener()
       {
             public void actionPerformed(ActionEvent ae)
             {
                  JOptionPane.showMessageDialog(null,"japplet example");
                
                 }
           }
           );
    }
   
    public void init()
    {
        System.out.println("in init");
        try{
            SwingUtilities.invokeAndWait(new Runnable(){
                public void run()
                {
                    go();
                   
                    }
            });
        }
         catch(Exception e){
            
               e.printStackTrace();
             }
        
    }
   
   public void paint(Graphics g)
   {
          //g.drawString("hi shailesh",10,10);
       }
}

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creating object from string in java

import java.io.*;
import java.awt.*;
import java.util.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.event.*;


   
   

class test{
   
   
    static void display()
    {
        System.out.println("this is display");
        }
   
    public static void main(String args[]) throws Exception
    {
       
    String s="test";
   
    ((test)Class.forName(s).newInstance()).display();
       
    }
       
    }   

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