Paint program

import java.awt.*;
import java.awt.event.*;
import java.awt.geom.Rectangle2D;

import javax.swing.*;
import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

import java.net.URL;
import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;


/**
 * This program demonstrates GradientPaint and TexturePaint.
 * This class has a main() routine and so can be run as an application.
 * The static nested class PaintDemo.Applet runs the program as an applet.
 */
public class PaintDemo extends JPanel {
   
   /**
    * The main routine simply opens a window that shows a PaintDemo panel.
    */
   public static void main(String[] args) {
      JFrame window = new JFrame("PaintDemo - Drag the Vertices");
      PaintDemo content = new PaintDemo();
      window.setContentPane(content);
      window.pack();  
      Dimension screenSize = Toolkit.getDefaultToolkit().getScreenSize();
      window.setLocation( (screenSize.width - window.getWidth())/2,
            (screenSize.height - window.getHeight())/2 );
      window.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );
      window.setVisible(true);
   }
   
   
   /**
    * The public static class PaintDemo$Applet represents this program
    * as an applet.  The applet's init() method simply sets the content 
    * pane of the applet to be a PaintDemo.  To use the applet on
    * a web page, use code="PaintDemo$Applet.class" as the name of
    * the class.  
    */
   public static class Applet extends JApplet {
      public void init() {
         PaintDemo content = new PaintDemo();
         setContentPane( content );
      }
   }
   
   
   /**
    * The display area of the program shows a filled polygon that can be filled
    * with various kinds of paint.  The vertices of the polygon can be dragged
    * by the user.
    */
   private class Display extends JPanel implements MouseListener, MouseMotionListener {
      int[] xcoord, ycoord;
      int draggedPoint = -1;
      Display() {
         setBackground(Color.WHITE);
         setPreferredSize(new Dimension(400,300));
         addMouseListener(this);
         addMouseMotionListener(this);
      }
      public void paintComponent(Graphics g) {
         super.paintComponent(g);
         Graphics2D g2 = (Graphics2D)g;
         if (xcoord == null) {
            xcoord = new int[] { scaleX(0.2), scaleX(0.8), scaleX(0.5),
                               scaleX(0.95), scaleX(0.35), scaleX(0.1) };
            ycoord = new int[] { scaleY(0.15), scaleY(0.1), scaleY(0.5),
                               scaleY(0.45), scaleY(0.9), scaleY(0.7) };
         }
         g2.setPaint(paint);
         g2.fillPolygon(xcoord, ycoord, 6);
         g2.setColor(Color.BLACK);
         g2.setStroke(new BasicStroke(2));
         g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                   RenderingHints.VALUE_ANTIALIAS_ON);
         g2.drawPolygon(xcoord, ycoord, 6);
         for (int i = 0; i < 6; i++)
            g2.fillRect(xcoord[i] - 3, ycoord[i] - 3, 7, 7);
      }
      private int scaleX(double x) {
         return (int)(x * getWidth());
      }
      private int scaleY(double y) {
         return (int)(y * getHeight());
      }
      public void mousePressed(MouseEvent e) {
         draggedPoint = -1;
         for (int i = 0; i < 6; i++) {
            if (Math.abs(xcoord[i] - e.getX()) < 4 && Math.abs(ycoord[i] - e.getY()) < 4) {
               draggedPoint = i;
               break;
            }
         }
      }
      public void mouseDragged(MouseEvent e) {
         if (draggedPoint < 0)
            return;
         int x = Math.max(0, Math.min(e.getX(),getWidth()));
         int y = Math.max(0, Math.min(e.getY(),getHeight()));
         xcoord[draggedPoint] = x;
         ycoord[draggedPoint] = y;
         repaint();
      }
      public void mouseReleased(MouseEvent e) { }
      public void mouseMoved(MouseEvent e) { }
      public void mouseClicked(MouseEvent e) { }
      public void mouseEntered(MouseEvent e) { }
      public void mouseExited(MouseEvent e) { }
   }
   

   /**
    * Responds when a use clicks on the radio button to set up the labels and sliders
    * to correspond to the kind of paint that has been selected.  Calls setPaint()
    * to make the display use the new selected paint.
    */
   private ActionListener buttonlistener = new ActionListener() {
      public void actionPerformed(ActionEvent e) {
         currentButton = (JRadioButton)e.getSource();
         slider1.removeChangeListener(sliderlistener);  //(Yuck! Had to do this to avoid notifying
         slider2.removeChangeListener(sliderlistener);  // sliderListener when changes are made.)
         if (currentButton == gradientButton1 || currentButton == gradientButton2) {
            label1.setText("  Gradient Angle:");
            label2.setText("  Gradient Width:");
            slider1.setMinimum(0);
            slider1.setMaximum(360);
            slider1.setValue(gradientAngle);
            slider2.setMinimum(10);
            slider2.setMaximum(300);
            slider2.setValue(gradientWidth);
         }
         else {
            label1.setText("  Texture Offset:");
            label2.setText("  Texture Scale:");
            slider1.setMinimum(0);
            slider1.setMaximum(100);
            slider1.setValue(textureOffset);
            slider2.setMinimum(25);
            slider2.setMaximum(200);
            slider2.setValue(textureScale);
         }
         slider1.addChangeListener(sliderlistener);
         slider2.addChangeListener(sliderlistener);
         setPaint();
      }
   };
   
   
   /**
    * When the user changes the value on one of the sliders, this 
    * ChangeListener responds by changing the Paint to reflect the
    * changed value.
    */
   private ChangeListener sliderlistener = new ChangeListener() {
      public void stateChanged(ChangeEvent e) {
         setPaint();
      }
   };
   
   
   /**
    * Called when the type of paint or the values on the sliders are changes, to
    * create the new Paint and redraw the display to show the change.
    */
   private void setPaint() {
      if (currentButton == gradientButton1 || currentButton == gradientButton2) {
         gradientAngle = slider1.getValue();
         gradientWidth = slider2.getValue();
         int x = getWidth()/2;
         int y = getHeight()/2;
         int dx = (int)( gradientWidth * Math.cos(gradientAngle/180.0 * Math.PI) );
         int dy = (int)( gradientWidth * Math.sin(gradientAngle/180.0 * Math.PI) );
         if (currentButton == gradientButton1)
            paint = new GradientPaint(x,y,Color.LIGHT_GRAY,x+dx,y+dy,Color.BLACK,true);
         else
            paint = new GradientPaint(x,y,Color.RED,x+dx,y+dy,Color.YELLOW,true);
      }
      else {
         textureOffset = slider1.getValue();
         textureScale = slider2.getValue();
         BufferedImage texture;
         if (currentButton == textureButton1)
            texture = smiley;
         else
            texture = queen;
         int width = texture.getWidth() * textureScale / 100;
         int height = texture.getHeight() * textureScale / 100;
         int offsetX = width * textureOffset / 100;
         int offsetY = height * textureOffset / 100;
         Rectangle2D anchor = new Rectangle2D.Double(offsetX,offsetY,width,height);
         paint = new TexturePaint(texture,anchor);
      }
      display.repaint();
   }
   
   
   private Display display = new Display();  // The display area where the polygon is drawn.
   
   private Paint paint;  // The paint that is used to fill the polygon in the display.
   
   private BufferedImage smiley, queen;  // Images for texture paint.

   private JRadioButton gradientButton1, gradientButton2;  // Select the type of paint.
   private JRadioButton textureButton1, textureButton2;

   private JRadioButton currentButton;   // The currently selected radion button.
   
   private int gradientAngle = 45, gradientWidth = 50;  // Settings that affect the paint.
   private int textureOffset = 0, textureScale = 100;
   
   private JSlider slider1, slider2;  // Sliders that control the settings;  Which 
                                      // setting is affect depends on currrent paint type.
   
   private JLabel label1 = new JLabel("  Gradient Angle:");  // Labels change, depending
   private JLabel label2 = new JLabel("  Gradient Width:");  //   on type of paint.
   
   
   /**
    * Constructor.
    */
   public PaintDemo() {
      setLayout(new BorderLayout(3,3));
      setBorder(BorderFactory.createLineBorder(Color.GRAY,3));
      setBackground(Color.GRAY);
      add(display, BorderLayout.CENTER);
      JPanel bottom = new JPanel();
      bottom.setLayout(new GridLayout(0,2,5,5));
      add(bottom, BorderLayout.SOUTH);
      slider1 = new JSlider(0,360,gradientAngle);
      slider1.addChangeListener(sliderlistener);
      slider2 = new JSlider(10,300,gradientWidth);
      slider2.addChangeListener(sliderlistener);
      bottom.add(label1);
      bottom.add(slider1);
      bottom.add(label2);
      bottom.add(slider2);
      ButtonGroup group = new ButtonGroup();
      gradientButton1 = new JRadioButton("Black/Gray Gradient");
      gradientButton1.addActionListener(buttonlistener);
      bottom.add(gradientButton1);
      group.add(gradientButton1);
      gradientButton1.setSelected(true);
      currentButton = gradientButton1;
      gradientButton2 = new JRadioButton("Red/Yellow Gradient");
      gradientButton2.addActionListener(buttonlistener);
      bottom.add(gradientButton2);
      group.add(gradientButton2);
      setPaint();
      try {
         ClassLoader cl = PaintDemo.class.getClassLoader();
         URL imageURL = cl.getResource("TinySmiley.png");
         if (imageURL != null)
            smiley = ImageIO.read(imageURL);
         imageURL = cl.getResource("QueenOfHearts.png");
            queen = ImageIO.read(imageURL);
      }
      catch (Exception e) {
         return;  // Can't load the images, so don't add the texture radion buttons.
      }
      textureButton1 = new JRadioButton("Smiley Face");
      textureButton1.addActionListener(buttonlistener);
      bottom.add(textureButton1);
      group.add(textureButton1);
      textureButton2 = new JRadioButton("Queen Of Hearts");
      textureButton2.addActionListener(buttonlistener);
      bottom.add(textureButton2);
      group.add(textureButton2);
   }

}

Database Connect

Practice with DataBase Connection




import java.sql.*;
import java.sql.ResultSet;
import javax.swing.JOptionPane;

/**
 *
 * @author Manish
 */
public class DBConnect {
    public Connection con;
    public Statement st;
    public ResultSet rs;
    public  DBConnect(){
        try {
            Class.forName("com.mysql.jdbc.Driver");
           Class.forName("sun.jdbc.odbc.JdbcOdbcDriver"); // for Ms Access
            con = DriverManager.getConnection("jdbc:mysql://localhost:3306/details","root","");
            con = DriverManager.getConnection("jdbc:odbc:demo");
            st = con.createStatement();
        } catch (Exception ex) {
           JOptionPane.showMessageDialog(null,"Error:"+ex,"Error Box",JOptionPane.ERROR_MESSAGE);
        }
    }

    public int getData(int getroll, String getpass ){
   
        int value=0;
   
        try {
            String query = "Select * from students where Roll="+getroll+" and Password='"+getpass+"'";
       
            rs= st.executeQuery(query);
            while(rs.next()){
             value= rs.getInt("Roll");
              }
       
        }
        catch (Exception e) {
        }
        finally{
                   try{ rs.close();
                    st.close();
                   }catch(Exception ex){
                   }
               
                    return value;
       
        }
 
    }
   public String getAdminData(String getID, String getpass ){
        String value=null;
        try {
            String query = "Select * from admin where ID='"+getID+"' and Password='"+getpass+"'";
            rs= st.executeQuery(query);
       
            while(rs.next()){
           
               value= rs.getString("ID");
           
         
            }
       
        }
        catch (Exception e) {
             JOptionPane.showMessageDialog(null, "Error:"+e);
        }
        finally{
               
           try{ rs.close();
                    st.close();
                   }
           catch(Exception ex){
           }
            return value;
        }
 
    }
}

Copy one file to another - An example

// Copies one file into another. The names of both files must
// be specified on the command line.

import java.io.*;

public class CopyFile {
  public static void main(String[] args) {
    // Terminate program if number of command-line arguments
    // is wrong
    if (args.length != 2) {
      System.out.println("Usage: java CopyFile source dest");
      System.exit(-1);
    }

    try {
      // Open source file for input and destination file for
      // output
      FileInputStream source = new FileInputStream(args[0]);
      FileOutputStream dest = new FileOutputStream(args[1]);

      // Set up a 512-byte buffer
      byte[] buffer = new byte[512];

      // Copy bytes from the source file to the destination
      // file, 512 bytes at a time
      while (true) {
        int count = source.read(buffer);
        if (count == -1)
          break;
        dest.write(buffer, 0, count);
      }

      // Close source and destination files
      source.close();
      dest.close();

    } catch (FileNotFoundException e) {
      System.out.println("File cannot be opened");
    } catch (IOException e) {
      System.out.println("I/O error during copy");
    }
  }
}

Client code Chat software

Now the Client code for our chat software compile it and run only after server code


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

class Clientnode

{
JButton sendbutton;
BufferedReader reader;
PrintWriter writer;
JTextField outgoing;
JTextArea incoming;
JTextField user;

public Clientnode() // constructor of outer class(creates the GUI interface)....
{
JFrame frame = new JFrame("CHATCLIENT");
JPanel mainpanel = new JPanel();
JLabel name = new JLabel("USERNAME");
user = new JTextField(20);
incoming = new JTextArea(10,30);
incoming.setLineWrap(true);
incoming.setWrapStyleWord(true);
incoming.setEditable(false);
outgoing = new JTextField(30);
sendbutton = new JButton("SEND");
JScrollPane scroller = new JScrollPane(incoming);
scroller.setVerticalScrollBarPolicy(ScrollPaneConstants.VERTICAL_SCROLLBAR_ALWAYS);
scroller.setHorizontalScrollBarPolicy(ScrollPaneConstants.HORIZONTAL_SCROLLBAR_ALWAYS);
mainpanel.add(name);
mainpanel.add(user);
mainpanel.add(scroller);
mainpanel.add(outgoing);
mainpanel.add(sendbutton);
sendbutton.addActionListener(new Write());
frame.getContentPane().add(BorderLayout.CENTER,mainpanel);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
connect(); // method connect() called..
Thread readingthread = new Thread(new Reading()); // creates a new Thread Object...
readingthread.start(); // starts the new Thread(calls the run() method )...
frame.setSize(400,310);
frame.setVisible(true);
 }

class Reading implements Runnable // inner class implementing Runnable interface 
{ // (the new thread class)

public void run() // the overridden run() method (what the new thread does.. )
{
String message;
try
{
while((message = reader.readLine()) != null)
{
System.out.println("read"+message);
incoming.append(message+"\n");
}
}
catch(Exception exc)
{
exc.printStackTrace();
}
}
}

class Write implements ActionListener // inner class(implementing ActionListener interface) 
{ // for the send button

public void actionPerformed(ActionEvent a) // the overridden actionperformed() method
{ // (called when the button clicks)for writing to the server
try
{
//user.getText().setColor(Color.blue);
writer.println(user.getText()+" - "+outgoing.getText());
System.out.println(outgoing.getText());
writer.flush();
}
catch(Exception ex)
{
ex.printStackTrace();
}
outgoing.setText("");
outgoing.requestFocus();

}

}

void connect() // method for establishing a connection with the server
{
try
{
Socket clientsocket = new Socket("127.0.0.1",4000); // requesting the local host(127.0.0.1),port no.4000 
//  for connection and creating
//  chained streams for reading
//  and writing to the socket.
InputStreamReader isr = new InputStreamReader(clientsocket.getInputStream());  
reader = new BufferedReader(isr);  
writer = new PrintWriter(clientsocket.getOutputStream());
System.out.println("connected");
}
catch(IOException e)
{
e.printStackTrace();
}
}

public static void main(String[] a) // the main() method
{
Clientnode cn = new Clientnode(); // creating an object of Clientnode class(constructor called)
}


}

Chat software

Here is the server side code for chat software just copy it down and compile and run 

import java.util.*;
import java.net.*;
import java.io.*;
class Server // outer class
{
PrintWriter writer;
ArrayList clientoutputstreams; // an Arraylist in which we keep adding writers of different clients
Socket clientsocket;
void go() // go() method which is called in main() method...
{
clientoutputstreams = new ArrayList();
try
{
ServerSocket ss = new ServerSocket(4000); // creating a Server at port no. 4000
while(true) // an infinite loop for accepting connection requests as
{ // long as the program is running..
clientsocket = ss.accept(); // accept() method which returns a Socket for communication
System.out.println(clientsocket);
System.out.println("clientsocket");
writer = new PrintWriter(clientsocket.getOutputStream());
clientoutputstreams.add(writer);
Thread t = new Thread(new Clienthandler(clientsocket)); // a new Thread object created and the Thread is
t.start(); //  started whenever a request is accepted....
}
}
catch(Exception e)
{e.printStackTrace();}

}
class Clienthandler implements Runnable // an inner class that implements Runnable interface
{ // making it a Thread class
Socket sock;
BufferedReader reader;
public Clienthandler(Socket clientsocket) // constructor of the inner Thread class that takes the
{ // Socket(returned by accept() method) as argument
// and creates a buffered reader for each client..
try
{
InputStreamReader isr = new InputStreamReader(clientsocket.getInputStream());
reader = new BufferedReader(isr);
}
catch(Exception Ex)
{Ex.printStackTrace();}
}

public void run() // the overridden run() method(what happens in
{ // the new Thread)
String message;
try
{
while((message = reader.readLine())  != null) // reads from each client text until it is null
{ // and stores it in String object 'message'
System.out.println(message);
writeToAll(message); // writeToAll() method called...
}
}
catch(Exception f)
{f.printStackTrace();}
}
} // inner class ends...
public void writeToAll(String message) // writeToAll() method takes the read texts
{ // from all clients,i.e.'message' and writes it to
Iterator it = clientoutputstreams.iterator(); // all the connected clients
while(it.hasNext())
{
try
{
PrintWriter writer = (PrintWriter) it.next();
writer.println(message);
System.out.print(message);
writer.flush();
}
catch(Exception c)
{c.printStackTrace();}
}
}
public static void main(String[] man) // main() method
{ // creates an object of Server class and calls
Server s = new Server(); // its go() method...
s.go();
}
} // outer class ends...

File Handling in Java

File Handling

import java.io.*;

/**

 *

 * @author Manish Kumar

 */

public class ByteFileInp {

    public static void main(String Mad[]){

        try{

            FileOutputStream fout = new FileOutputStream("man.txt",true);

            String msz="Today you r cele";

            byte arr[]= msz.getBytes();

            fout.write(arr);

            fout.close();

             FileInputStream finp = new FileInputStream("man.txt");

             byte data[] = new byte[finp.available()];

             finp.read(data);

             String str = new String(data);

             System.out.println(str);

             finp.close();

        }

        catch(Exception e){

            System.err.println("Error is Here"+e);

        }

      

    }

}

Another Program

import java.io.*;

class FileHand

{

 public static void main(String args[]){

 try{

  FileOutputStream fout = new FileOutputStream("hello Manish",false);

  String msz="Today you r celebrating 68th Independence Day";

  byte arr[]= msz.getBytes();

  fout.write(arr);

  fout.close();

  }

  catch(Exception e){

   System.out.println("Manish You Have Error");

  }

 }

}

Layout mangers

Layout mangers
Layout manager is used to layout (or arrange) the GUI components inside a container.There are many layout managers , but the most frequently used are-
BorderLayout

A BorderLayout places components in up to five areas: top, bottom, left, right, and center. It is the default layout manager for every JFrame

java-border-layout-manager

FlowLayout
FlowLayout is the default layout manager for every JPanel. It simply lays out components in a single row one after the other.

java-flow-layout-manager

GridBagLayout

It is the more sophisticated of all layouts. It aligns components by placing them within a grid of cells, allowing components to span more than one cell.

java-grid-bag-layout

Step 8) How about creating a chat frame like below.

java-swing-chat-frame


//Usually you will require both swing and awt packages
// even if you are working with just swings.
import javax.swing.*;
import java.awt.*;
class gui{
public static void main(String args[]){
//Creating the Frame
JFrame frame = new JFrame("Chat Frame");
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setSize(400,400);
//Creating the MenuBar and adding components
JMenuBar mb = new JMenuBar();
JMenu m1 = new JMenu("FILE");
JMenu m2 = new JMenu("Help");
mb.add(m1);
mb.add(m2);
JMenuItem m11 = new JMenuItem("Open");
JMenuItem m22 =new JMenuItem("Save as");
m1.add(m11);
m1.add(m22);
//Creating the panel at bottom and adding components
JPanel panel = new JPanel(); // the panel is not visible in output
JLabel label = new JLabel("Enter Text");
JTextField tf = new JTextField(10);// accepts upto 10 characters
JButton send = new JButton("Send");
JButton reset = new JButton("Reset");
panel.add(label);// Components Added using Flow Layout
panel.add(tf);
panel.add(send);
panel.add(reset);
// Text Area at the Center
JTextArea ta = new JTextArea();
//Adding Components to the frame.
frame.getContentPane().add(BorderLayout.SOUTH,panel);
frame.getContentPane().add(BorderLayout.NORTH,mb);
frame.getContentPane().add(BorderLayout.CENTER,ta);
frame.setVisible(true);
}
}