驗證碼圖片生成器：http://pan.baidu.com/s/1kUL25Cz

生成算法Algorithm.java

package PictureVerification;

import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.image.BufferedImage;
  
public class Algorithm{  
    private static final int size=6;
    private static final int WIDTH=30*size;
    private static final int HEIGHT=40;
    private static final int lineNum=6;
    private char[] cstr=new char[size];
    public Algorithm() {}
    public Image generate(){
        int width=WIDTH/size;
        int height=HEIGHT;
        BufferedImage imagebuf=new BufferedImage(width*size,height, BufferedImage.TYPE_INT_RGB);        
        Graphics2D g=imagebuf.createGraphics();    
        int base=0;
        for(int i=1;i<size-1;i++){
            base=width*i;
            Font font =new Font("Tahoma",Font.ITALIC,(int)((Math.random()*(30-10))+10));
            g.setFont(font);
            double redix = Math.PI*Math.random()/2-Math.PI/4;
            g.rotate(redix,base+width/2, height/2);
            String str=""+(int)(Math.random()*10);
            cstr[i]=str.charAt(0);
            g.drawString(str,(int)(base*(1.2)),(int)(height*(0.8)));
            g.rotate(-redix,base+width/2, height/2);
        }
        
        //加線條
        for(int i=0;i<lineNum;i++){
            g.setColor(new Color((int)(Math.random()*255),(int)(Math.random()*255),(int)(Math.random()*255)));
            int a=(int)(Math.random()*WIDTH);
            int b=(int)(Math.random()*HEIGHT);
            int c=(int)(Math.random()*WIDTH);
            int d=(int)(Math.random()*HEIGHT);
            g.drawLine(a, b,c,d);
        }
        return imagebuf;
    }
    public String getStr(){
        return new String(cstr, 1, cstr.length-2);
    }
}  

View Code

MenuView.java（展示類）

package PictureVerification;

import java.awt.AWTException;
import java.awt.BorderLayout;
import java.awt.EventQueue;
import java.awt.Graphics2D;
import java.awt.Robot;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;

public class MenuView extends JFrame {

    /**
     * 
     */
    private static final long serialVersionUID = 1L;
    private JPanel contentPane;
    private JFrame f=this;
    private JPanel panel;
    private JLabel label;
    private ImageIcon image;
    private  BufferedImage imagebuf;
    private JButton btnNewButton_1;
    private JLabel lblNewLabel;
    private Algorithm algo=new Algorithm();

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    MenuView frame = new MenuView();
                    //MyCanvas m=new MyCanvas();  
                    JFrame f=frame;  
                    //f.getContentPane().add(m);    
                
                    //f.setLayout(null);  
                    f.setVisible(true);  
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public MenuView() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 301, 256);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);
        
        panel = new JPanel(new BorderLayout());
        image=new ImageIcon("");
        label=new JLabel("",image,JLabel.CENTER);
        panel.add(label,BorderLayout.CENTER);
        
        panel.setBounds(31, 30, 221, 97);
        
        contentPane.add(panel);
        
        JButton btnNewButton = new JButton("generate");
        btnNewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                loadImage();
            }
        });
        btnNewButton.setBounds(56, 174, 93, 23);
        contentPane.add(btnNewButton);
        
        btnNewButton_1 = new JButton("save");
        btnNewButton_1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                saveImage();
            }
        });
        btnNewButton_1.setBounds(159, 174, 93, 23);
        contentPane.add(btnNewButton_1);
        
        lblNewLabel = new JLabel("");
        lblNewLabel.setBounds(120, 137, 54, 15);
        contentPane.add(lblNewLabel);
    }
    private void loadImage(){
        image=new ImageIcon(algo.generate());
        label.setIcon(image);
        lblNewLabel.setText(algo.getStr());
    }
    private void saveImage(){
        BufferedImage imagebuf=null;;
        try {
            imagebuf = new Robot().createScreenCapture(panel.bounds());
        } catch (AWTException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }  
         Graphics2D graphics2D = imagebuf.createGraphics();
         panel.paint(graphics2D);
         try {
            ImageIO.write(imagebuf,"png", new File(algo.getStr()+".png"));
        } catch (Exception e) {
            // TODO Auto-generated catch block
            System.out.println("error");
        }
    }
}

View Code

下面是一我做這個隨機碼圖片生成器的一些些技術細節：

需求：

1、展示：一個界面，點擊生成按鈕就能夠生成一張驗證碼圖片；點擊保存按鈕能夠把圖片保存到當前文件夾；

在一個JPanel中顯示圖片：

        JPanel panel = new JPanel(new BorderLayout());
        ImageIcon image=new ImageIcon("1.png");
        JLabel label=new JLabel("",image,JLabel.CENTER);
        panel.add(label,BorderLayout.CENTER);        
        panel.setBounds(31, 30, 221, 121);

能夠把JFrame存為圖片：

package PictureVerification;

import java.awt.AWTException;
import java.awt.BorderLayout;
import java.awt.Canvas;
import java.awt.Color;
import java.awt.EventQueue;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.Robot;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.image.BufferedImage;
import java.io.File;

import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.border.EmptyBorder;
class MyCanvas extends Canvas{  
    
    public void paint(Graphics g) {  
  
        Toolkit t=Toolkit.getDefaultToolkit();  
        Image i=t.getImage("1.png");  
        g.drawImage(i, 120,100,this);  
          
    }    
}  
class DisplayGraphics extends Canvas{  
    
    public void paint(Graphics g) {
        int num=(int)(Math.random()*10);
        g.drawString(""+num, 10, 10);
        //g.drawString("Hello",40,40);  
        setBackground(Color.WHITE);  
        g.fillRect(130, 30,100, 80);  
        g.drawOval(30,130,50, 60);  
        setForeground(Color.RED);  
        g.fillOval(130,130,50, 60);  
        g.drawArc(30, 200, 40,50,90,60);  
        g.fillArc(30, 130, 40,50,180,40);  
          
    }  
}
public class Mine extends JFrame {

    private JPanel contentPane;
    private JFrame f=this;
    private JPanel panel;
    private JLabel label;
    private ImageIcon image;
    private  BufferedImage imagebuf;
    private JButton btnNewButton_1;

    /**
     * Launch the application.
     */
    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            public void run() {
                try {
                    Mine frame = new Mine();
                    //MyCanvas m=new MyCanvas();  
                    JFrame f=frame;  
                    //f.getContentPane().add(m);    
                
                    //f.setLayout(null);  
                    f.setVisible(true);  
                    frame.setVisible(true);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        });
    }

    /**
     * Create the frame.
     */
    public Mine() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        setBounds(100, 100, 301, 256);
        contentPane = new JPanel();
        contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
        setContentPane(contentPane);
        contentPane.setLayout(null);
        
        JPanel panel = new JPanel(new BorderLayout());
        ImageIcon image=new ImageIcon("");
        label=new JLabel("",image,JLabel.CENTER);
        panel.add(label,BorderLayout.CENTER);
        
        panel.setBounds(31, 30, 221, 121);
        
        contentPane.add(panel);
        
        JButton btnNewButton = new JButton("generate");
        btnNewButton.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                loadImage();
            }
        });
        btnNewButton.setBounds(56, 174, 93, 23);
        contentPane.add(btnNewButton);
        
        btnNewButton_1 = new JButton("save");
        btnNewButton_1.addActionListener(new ActionListener() {
            public void actionPerformed(ActionEvent arg0) {
                saveImage();
            }
        });
        btnNewButton_1.setBounds(159, 174, 93, 23);
        contentPane.add(btnNewButton_1);
    }
    private void loadImage(){
        image=new ImageIcon("1.png");
        label.setIcon(image);
    }
    private void saveImage(){
         //imagebuf = new BufferedImage(getWidth(), getHeight(), BufferedImage.TYPE_INT_RGB);
        BufferedImage imagebuf=null;;
        try {
            imagebuf = new Robot().createScreenCapture(   
                        new Rectangle( getX(), getY(), getWidth(), getHeight() ) );
        } catch (AWTException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }  
         Graphics2D graphics2D = imagebuf.createGraphics();
         paint(graphics2D);
         System.out.println("before save");
         try {
            ImageIO.write(imagebuf,"jpeg", new File("save1.jpeg"));
        } catch (Exception e) {
            // TODO Auto-generated catch block
            System.out.println("error");
        }
    }
}

View Code

保存單個JPanel：

    private void saveImage(){
        BufferedImage imagebuf=null;;
        try {
            imagebuf = new Robot().createScreenCapture(panel.bounds());
        } catch (AWTException e1) {
            // TODO Auto-generated catch block
            e1.printStackTrace();
        }  
         Graphics2D graphics2D = imagebuf.createGraphics();
         panel.paint(graphics2D);
         try {
            ImageIO.write(imagebuf,"jpeg", new File("save1.jpeg"));
        } catch (Exception e) {
            // TODO Auto-generated catch block
            System.out.println("error");
        }
    }

View Code

2、生成算法：返回值為Image

（1）直接的純文本

可以設置字體，大小，顏色

（2）純文本加噪聲

加線條

（3）調整大小方位

旋轉

（4）使用矩陣變換進行扭曲

仿射變化

java中的robot類

Image轉BufferedImage

BufferedImage image = ImageIO.read(new File(filename));

public static BufferedImage toBufferedImage(Image img)
{
    if (img instanceof BufferedImage)
    {
        return (BufferedImage) img;
    }

    // Create a buffered image with transparency
    BufferedImage bimage = new BufferedImage(img.getWidth(null), img.getHeight(null), BufferedImage.TYPE_INT_ARGB);

    // Draw the image on to the buffered image
    Graphics2D bGr = bimage.createGraphics();
    bGr.drawImage(img, 0, 0, null);
    bGr.dispose();

    // Return the buffered image
    return bimage;
}

旋轉繪圖：

        BufferedImage imagebuf=ImageIO.read(new File("test2.png"));
        Graphics2D g=imagebuf.createGraphics();        
        g.rotate(0.5, 50, 25);
        g.drawString("hello", 100,50);
        ImageIO.write(imagebuf,"png", new File("test22.png"));

import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;

import javax.imageio.ImageIO;


public class Test {

    public static void main(String[] args) throws IOException {
        // TODO Auto-generated method stub
        BufferedImage imagebuf=new BufferedImage(200, 200, BufferedImage.TYPE_INT_RGB);        
        Graphics2D g=imagebuf.createGraphics();    
        g.drawString("hello", 80,120);
        AffineTransform transtate=new AffineTransform();
        transtate.translate(18,10);
        AffineTransform scale=AffineTransform.getScaleInstance(300/100, 350/50);
        AffineTransform tx=g.getTransform();
        tx.concatenate(scale);
        tx.concatenate(transtate);
        g.setTransform(tx);
        g.drawString("hello", 10,5);
        g.rotate(Math.PI, 10, 5);
        g.drawString("hello", 10,5);
        ImageIO.write(imagebuf,"png", new File("test22.png"));
    }

}

View Code

圖片的仿射變化：http://docs.geotools.org/stable/userguide/tutorial/affinetransform.html#

可以翻轉，移動縮放圖片。

關鍵技術就是這些，最完后就是上面的樣子。

最后介紹一個開源的驗證碼項目：http://jcaptcha.sourceforge.net/

總結

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