簡單的隨機生成4個驗證碼的實現

</pre><pre name="code" class="java">VerifyCode類：生成四個隨機驗證碼


package cn.itcast.image;


import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import java.util.Random;


import javax.imageio.ImageIO;


public class VerifyCode {
    private int w = 70;
    private int h = 35;
     private Random r = new Random();
     // {"宋體", "華文楷體", "黑體", "華文新魏", "華文隸書", "微軟雅黑", "楷體_GB2312"}
    private String[] fontNames  = {"宋體", "華文楷體", "黑體", "微軟雅黑", "楷體_GB2312"};
    // 可選字符
    private String codes  = "23456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ";
    // 背景色
    private Color bgColor  = new Color(255, 255, 255);
    // 驗證碼上的文本
    private String text ;
    
    // 生成隨機的顏色
    private Color randomColor () {
        int red = r.nextInt(150);
        int green = r.nextInt(150);
        int blue = r.nextInt(150);
        return new Color(red, green, blue);
    }
    
    // 生成隨機的字體
    private Font randomFont () {
        int index = r.nextInt(fontNames.length);
        String fontName = fontNames[index];//生成隨機的字體名稱
        int style = r.nextInt(4);//生成隨機的樣式, 0(無樣式), 1(粗體), 2(斜體), 3(粗體+斜體)
        int size = r.nextInt(5) + 24; //生成隨機字號, 24 ~ 28
        return new Font(fontName, style, size);
    }
    
    // 畫干擾線
    private void drawLine (BufferedImage image) {
        int num  = 3;//一共畫3條
        Graphics2D g2 = (Graphics2D)image.getGraphics();
        for(int i = 0; i < num; i++) {//生成兩個點的座標，即4個值
            int x1 = r.nextInt(w);
            int y1 = r.nextInt(h);
            int x2 = r.nextInt(w);
            int y2 = r.nextInt(h); 
            g2.setStroke(new BasicStroke(1.5F)); 
            g2.setColor(Color.BLUE); //干擾線是藍色
            g2.drawLine(x1, y1, x2, y2);//畫線
        }
    }
    
    // 隨機生成一個字符
    private char randomChar () {
        int index = r.nextInt(codes.length());
        return codes.charAt(index);
    }
    
    // 創建BufferedImage
    private BufferedImage createImage () {
        BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); 
        Graphics2D g2 = (Graphics2D)image.getGraphics(); 
        g2.setColor(this.bgColor);
        g2.fillRect(0, 0, w, h);
         return image;
    }
    
    // 調用這個方法得到驗證碼
    public BufferedImage getImage () {
        BufferedImage image = createImage();//創建圖片緩衝區 
        Graphics2D g2 = (Graphics2D)image.getGraphics();//得到繪製環境
        StringBuilder sb = new StringBuilder();//用來裝載生成的驗證碼文本
        // 向圖片中畫4個字符
        for(int i = 0; i < 4; i++)  {//循環四次，每次生成一個字符
            String s = randomChar() + "";//隨機生成一個字母 
            sb.append(s); //把字母添加到sb中
            float x = i * 1.0F * w / 4; //設置當前字符的x軸座標
            g2.setFont(randomFont()); //設置隨機字體
            g2.setColor(randomColor()); //設置隨機顏色
            g2.drawString(s, x, h-5); //畫圖
        }
        this.text = sb.toString(); //把生成的字符串賦給了this.text
        drawLine(image); //添加干擾線
        return image;        
    }
    
    // 返回驗證碼圖片上的文本
    public String getText () {
        return text;
    }
    
    // 保存圖片到指定的輸出流
    public static void output (BufferedImage image, OutputStream out) 
                throws IOException {
        ImageIO.write(image, "JPEG", out);
    }
}


調用方法
    @Test
    public void demo() throws FileNotFoundException, IOException{
        VerifyCode vc = new VerifyCode();
        BufferedImage bi = vc.getImage();
        VerifyCode.output(bi, new FileOutputStream("F:xxx.jpg"));
        System.out.println(vc.getText());
    }