JDBC CONNECTVITY

//JDBC
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import java.lang.StringBuffer;
import java.io.IOException;
import java.io.*;
import java.sql.*;
public class AddressBookDataBase extends JFrame
{
private DataPanel myDataPanel;
private Connection dbconn;
private static int numPeople=0;
private static String info;
private static JTextArea txtInfo=new JTextArea( 8, 40 );
public AddressBookDataBase()
{
super("This is my Phone Book which calls a database, La La La");
GridLayout myGridLayout= new GridLayout(3,1);
Container p = getContentPane();
myDataPanel=new DataPanel();
p.add(myDataPanel);
myDataPanel.setLayout(myGridLayout);
try
{
String url = "jdbc:odbc:myAddressBook";
Class.forName( "sun.jdbc.odbc.JdbcOdbcDriver" );
dbconn = DriverManager.getConnection( url );
info="Connection successful\n";
}
catch ( ClassNotFoundException cnfex )
{
cnfex.printStackTrace();
info=info+"Connection unsuccessful\n" + cnfex.toString();
}
catch ( SQLException sqlex )
{
sqlex.printStackTrace();
info=info+"Connection unsuccessful\n" +sqlex.toString();
}
catch ( Exception excp )
{
excp.printStackTrace();
info=info+excp.toString();
}
txtInfo.setText(info
setSize(500,290);
setVisible(true);
}
public static void main(String args[])
{
AddressBookDataBase myAddressBookDataBase= new AddressBookDataBase();
myAddressBookDataBase.addWindowListener
(
new WindowAdapter()
{
public void windowClosing(WindowEvent e)
{
System.exit(0);
}
}
);
}
class DataPanel extends JPanel implements ActionListener
{
JLabel lblIDCap= new JLabel("Record Number");
JLabel lblLast=new JLabel("Last Name");
JLabel lblFirst=new JLabel("First Name");
JLabel lblPhone=new JLabel("Phone Number");
//JTextArea txtInfo=new JTextArea();
JLabel lblID=new JLabel(" "); //10 spaces
JTextField txtLast=new JTextField(10);
JTextField txtFirst=new JTextField(10);
JTextField txtPhone=new JTextField(10);
JButton btnAdd=new JButton("Add Record");
JButton btnFind=new JButton("Find Record");
JButton btnDelete=new JButton("Delete Record");
JButton btnUpdate=new JButton("Update Record");
JButton btnClear=new JButton("Clear");
JButton btnExit=new JButton("Exit");
public DataPanel()
{
JPanel myPanel = new JPanel();
JPanel myPanel2 = new JPanel();
JPanel myPanel3 =new JPanel();
myPanel.setLayout(new GridLayout (4,2)); //4 rows 2 cols
myPanel2.setLayout(new GridLayout (2,3)); //2 rows 3 cols
myPanel3.setLayout(new GridLayout(1,1)); //1 row 1 col
add(myPanel);
add(myPanel2);
add(myPanel3);
myPanel.add(lblIDCap);
myPanel.add(lblID);
myPanel.add(lblLast);
myPanel.add(txtLast);
myPanel.add(lblFirst);
myPanel.add(txtFirst);
myPanel.add(lblPhone);
myPanel.add(txtPhone);
myPanel2.add(btnAdd);
myPanel2.add(btnFind);
myPanel2.add(btnDelete);
myPanel2.add(btnUpdate);
myPanel2.add(btnClear);
myPanel2.add(btnExit);
myPanel3.add( new JScrollPane(txtInfo));
//puts txtInfo on application and allows it to scroll
btnAdd.addActionListener(this);
btnFind.addActionListener(this);
btnUpdate.addActionListener(this);
btnClear.addActionListener(this);
btnExit.addActionListener(this);
btnDelete.addActionListener(this);
}
public void actionPerformed(ActionEvent event)
{
String ID=""; //must initialize to ""
String Last="";
String First="";
String Phone="";
Object source=event.getSource();
ID=lblID.getText().trim();
lblID.setText(ID);
Last=txtLast.getText().trim();
txtLast.setText(Last);
First=txtFirst.getText().trim();
txtFirst.setText(First);
Phone=txtPhone.getText().trim();
txtPhone.setText(Phone);
if (source.equals(btnAdd))
{
try {
Statement statement = dbconn.createStatement();
if ( !Last.equals( "" ) &&
!First.equals( "" ) &&
!Phone.equals("") )
{
String temp = "INSERT INTO AddressTable (" +
"Last, First, Phone" +
") VALUES ('" +
Last + "', '" +
First + "', '" +
Phone +
"')";
txtInfo.append( "\nInserting: " +
dbconn.nativeSQL( temp ) + "\n" );
int result = statement.executeUpdate( temp );
if ( result == 1 )
{ //confirming insertion
//txtInfo.append("\nInsertion successful\n");
String query="";
try
{
query = "SELECT * FROM AddressTable WHERE First='" +
First + "' AND Last= '" + Last + "'";
ResultSet rs = statement.executeQuery( query );
rs.next();
lblID.setText(String.valueOf(rs.getInt(1)));
}
catch ( SQLException sqlex )
{
txtInfo.append( sqlex.toString() );
}
}
else
{
txtInfo.append( "\nInsertion failed\n" );
txtFirst.setText( "" );
txtLast.setText( "" );
txtPhone.setText( "" );
}
}
else
txtInfo.append( "\nEnter last, first, " +
"phone and address, then press Add\n" );
statement.close();
}
catch ( SQLException sqlex )
{
txtInfo.append( sqlex.toString() );
txtFirst.setText("Entry already exists -- re-enter");
}
}
if (source.equals(btnFind))
{
try
{
if ( !Last.equals("") && !First.equals(""))
{
txtPhone.setText("Not Found");
Statement statement =dbconn.createStatement();
String query = "SELECT * FROM AddressTable " +
"WHERE First = '" +
First + "'"+
" AND Last = '" +
Last + "'";
txtInfo.append( "\nSending query: " +
dbconn.nativeSQL( query ) + "\n" );
ResultSet rs = statement.executeQuery( query );
display( rs );
statement.close();
}
else
txtLast.setText("Enter last name and First name"+
" then press Find" );
}
catch ( SQLException sqlex )
{
txtInfo.append( sqlex.toString() + sqlex.getMessage() );
}
}
if (source.equals(btnUpdate))
{
try
{
Statement statement = dbconn.createStatement();
if ( ! lblID.getText().equals(""))
{
String temp = "UPDATE AddressTable SET " +
"First='" + txtFirst.getText() +
"', Last='" + txtLast.getText() +
"', Phone='" + txtPhone.getText() +
"' WHERE id=" + lblID.getText();
txtInfo.append( "\nUpdating: " +
dbconn.nativeSQL( temp ) + "\n" );
int result = statement.executeUpdate( temp );
if ( result == 1 )
txtInfo.append( "\nUpdate successful\n" );
else {
txtInfo.append( "\nUpdate failed\n" );
txtFirst.setText( "" );
txtLast.setText( "" );
txtPhone.setText( "" );
}
statement.close();
}
else
txtInfo.append( "\nYou may only update an " +
"existing record. Use Find to " +
"\nlocate the record, then " +
"modify the information and " +
"\npress Update.\n" );
}
catch ( SQLException sqlex ) {
txtInfo.append( sqlex.toString() );
}
}
if (source.equals(btnDelete))
{
try
{
Statement statement = dbconn.createStatement();
if ( ! lblID.getText().equals(""))
{
System.out.print(lblID.getText());
String temp = "DELETE from AddressTable " +
" WHERE id=" + lblID.getText();
txtInfo.append( "\nDeleting: " +
dbconn.nativeSQL( temp ) + "\n" );

int result = statement.executeUpdate( temp );
if ( result == 1 )
{
txtInfo.append( "\nDeletion successful\n" );
}
else
{
txtInfo.append( "\nDeletion failed\n" );
txtFirst.setText( "" );
txtLast.setText( "" );
txtPhone.setText( "" );
}
statement.close();
}
else
txtInfo.append( "\nYou may only delete an " +
"existing record. Use Find to " +
"\nlocate the record, then " +
"press delete.\n" );
}
catch ( SQLException sqlex )
{
txtInfo.append( sqlex.toString() );
}
}
if (source.equals(btnClear))
{
txtLast.setText("");
txtFirst.setText("");
txtPhone.setText("");
lblID.setText("");
}
if (source.equals(btnExit))
{
System.exit(0);
}
}
public void display( ResultSet rs )
{
try
{
rs.next();
int recordNumber = rs.getInt( 1 );
if ( recordNumber != 0 )
{
lblID.setText( String.valueOf(recordNumber) );
txtLast.setText( rs.getString( 2 ) );
txtFirst.setText( rs.getString( 3 ) );
txtPhone.setText( rs.getString( 4 ) );
}
else
{
txtInfo.append( "\nNo record found\n" );
}
}
catch ( SQLException sqlex )
{
txtInfo.append( "\n*** Information Not In Database ***\n" );
}
}
}
}

Select the data from database

//Select the data from database
import java.io.*;
import javax.servlet.http.*;
import java.sql.*;
public class Update extends HttpServlet{
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException{
response.setContentType("text/html");
PrintWriter pw = response.getWriter();
String url=" ";
Connection cont;
try
{
url="jdbc:odbc:AddressBook1";
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
cont=DriverManager.getConnection(url);
Statement statement=cont.createStatement();
String query="SELECT * FROM addresses WHERE ID= '"+ request.getParameter ("number") + "'";
ResultSet rs=statement.executeQuery(query);
while(rs.next())
{
String recnum=rs.getString(1);
if(recnum.equals(request.getParameter("number")))
{
pw.println("

Number:" +recnum+"

");
pw.println("

Name:" +rs.getString(2)+"

");
pw.println("

E-mail:" +rs.getString(4)+"

");
pw.println("

Phone:"+rs.getString(5)+"

");
}
else
{
pw.println("No record found");
}
}
statement.close();
}
catch(Exception e)
{
pw.println(e.toString());
}
}
}

Insert the data into a database

import java.io.*;
import javax.servlet.http.*;
import java.sql.*;
public class Update extends HttpServlet{
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws IOException{
response.setContentType("text/html");
PrintWriter pw = response.getWriter();
String url=" ";
Connection cont;
try
{
url="jdbc:odbc:AddressBook1";
Class.forName("sun.jdbc.odbc.JdbcOdbcDriver");
cont=DriverManager.getConnection(url);
Statement statement=cont.createStatement();
String query="INSERT INTO addresses Values ( '"+ request.getParameter ("number") + "','"+
request.getParameter("username")+"','"+request.getParameter("password")+"','"+ request.getParameter("email")+"','"+ request.getParameter("phone")+"')";
int result = statement.executeUpdate(query);
if (result == 1)
pw.println("Data was Inserted");
else
pw.println ("Data was not Inserted");
statement.close();
cont.close();
}
catch(Exception e)
{
pw.println(e.toString());
}
}
}

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Handling HTTP POST Requests

Handling HTTP POST Requests

The following servlet handles an HTTP POST request. The servlet is invoked when a form on a Web page is submitted. The example contains two files. A Web page is defined in ColorPost.html and a servlet is defined in ColorPostServlet.java.

ColorPost.html

<html>

<body>

<center>

<form name="Form1" method="post"action="http://localhost:8080/servlets-examples /servlet/ColorPostServlet">

<B>Color:</B>

<select name="color" size="1">

<option value="Red">Red</option>

<option value="Green">Green</option>

<option value="Blue">Blue</option>

</select>

<br><br>

<input type=submit value="Submit">

</form>

</body>

</html>

ColorPostServlet.java

import java.io.*;

import javax.servlet.*;

import javax.servlet.http.*;

public class ColorPostServlet extends HttpServlet

{

public void doPost(HttpServletRequest request,

HttpServletResponse response)throws ServletException, IOException

{

String color = request.getParameter("color");

response.setContentType("text/html");

PrintWriter pw = response.getWriter();

pw.println("<B>The selected color is: ");

pw.println(color);

pw.close();

}

}

Handling HTTP Get Requests

Handling HTTP GET Requests

The following servlet handles an HTTP GET request. The servlet is invoked when a form on a Web page is submitted. The example contains two files. A Web page is defined in ColorGet.html and a servlet is defined in ColorGetServlet.java. The HTML source code for ColorGet.htm is shown in the following listing. It defines a form that contains a select element and a submit button. Notice that the action parameter of the form tag specifies a URL. The URL identifies a servlet to process the HTTP GET request.

ColorGet.html Program:

<html>

<body>

<center>

<form name="Form1"

action="http://localhost:8080/servlets-examples/servlet/ColorGetServlet">

<B>Color:</B>

<select name="color" size="1">

<option value="Red">Red</option>

<option value="Green">Green</option>

<option value="Blue">Blue</option>

</select>

<br><br>

<input type=submit value="Submit">

</form>

</body>

</html>

ColorGetServlet.java:

import java.io.*;

import javax.servlet.*;

import javax.servlet.http.*;

public class ColorGetServlet extends HttpServlet

{

public void doGet(HttpServletRequest request,HttpServletResponse response)throws ServletException, IOException

{

String color = request.getParameter("color");

response.setContentType("text/html");

PrintWriter pw = response.getWriter();

pw.println("<B>The selected color is: ");

pw.println(color);

pw.close();

}

}