一个验证码的Java轮子

import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.ServletException;
import javax.servlet.http.*;

/**
*

• @author administrator
  */

public class CheckCode extends HttpServlet {

public CheckCode() {
    super();
}

// 获取随机颜色
public Color getRandColor(int s, int e) {
    Random random = new Random();
    if (s > 255) s = 255;
    if (e > 255) e = 255;
    int r = s + random.nextInt(e - s);        //随机生成RGB颜色中的r值
    int g = s + random.nextInt(e - s);        //随机生成RGB颜色中的g值
    int b = s + random.nextInt(e - s);        //随机生成RGB颜色中的b值
    return new Color(r, g, b);
}

public void service(HttpServletRequest request, HttpServletResponse response)
        throws ServletException, IOException {
    response.setHeader("Pragma", "No-cache");
    response.setHeader("Cache-Control", "No-cache");
    response.setDateHeader("Expires", 0);
    // 指定生成的响应是图片
    response.setContentType("image/jpeg");
    int width = 116;            //指定验证码的宽度
    int height = 33;            //指定验证码的高度
    
    BufferedImage image = new BufferedImage(width, height,
            BufferedImage.TYPE_INT_RGB);
    Graphics g = image.getGraphics();       //获取Graphics类的对象
    Random random = new Random();               //实例化一个Random对象
    Font mFont = new Font("宋体", Font.BOLD, 22);   //通过Font构造字体
    g.fillRect(0, 0, width, height);                //绘制验证码背景
    g.setFont(mFont);           //设置字体
    g.setColor(getRandColor(180, 200));     //设置颜色
    // 画随机的线条
    for (int i = 0; i < 100; i++) {
        int x = random.nextInt(width - 1);
        int y = random.nextInt(height - 1);
        int x1 = random.nextInt(3) + 1;
        int y1 = random.nextInt(6) + 1;
        g.drawLine(x, y, x + x1, y + y1);       //绘制直线
    }
    /**************************画一条折线********************************/        
    BasicStroke bs=new BasicStroke(2f,BasicStroke.CAP_BUTT,BasicStroke.JOIN_BEVEL);    //创建一个供画笔选择线条粗细的对象
    Graphics2D g2d = (Graphics2D) g;    //通过Graphics类的对象创建一个Graphics2D类的对象
    g2d.setStroke(bs);                    //改变线条的粗细
    g.setColor(Color.GRAY);        //设置当前颜色为预定义颜色中的灰色
    int lineNumber=4;        //指定端点的个数
    int[] xPoints=new int[lineNumber];      //定义保存x轴坐标的数组
    int[] yPoints=new int[lineNumber];      //定义保存x轴坐标的数组
    //通过循环为x轴坐标和y轴坐标的数组赋值
    for(int j=0;j<lineNumber;j++){
        xPoints[j]=random.nextInt(width - 1);
        yPoints[j]=random.nextInt(height - 1);
    }
    g.drawPolyline(xPoints, yPoints,lineNumber);    //绘制折线
    /*******************************************************************/
    String sRand = "";
    // 输出随机的验证文字
     for (int i = 0; i < 4; i++) {
        char ctmp = (char)(random.nextInt(26) + 65);    //生成A~Z的字母
        sRand += ctmp;
        Color color = new Color(20 + random.nextInt(110), 20 + random
                .nextInt(110), 20 + random.nextInt(110));
        g.setColor(color);              //设置颜色
        /** **随机缩放文字并将文字旋转指定角度* */
        // 将文字旋转指定角度
        Graphics2D g2d_word = (Graphics2D) g;
        AffineTransform trans = new AffineTransform();
        trans.rotate(random.nextInt(45) * 3.14 / 180, 22 * i + 8, 7);
        // 缩放文字
        float scaleSize = random.nextFloat() +0.8f;
        if (scaleSize > 1f)    scaleSize = 1f;
        trans.scale(scaleSize, scaleSize);          //进行缩放
        g2d_word.setTransform(trans);
        /** ********************* */
        g.drawString(String.valueOf(ctmp), width/6 * i+23, height/2);

    }
    // 将生成的验证码保存到Session中
    HttpSession session = request.getSession(true);
    session.setAttribute("randCheckCode", sRand);
    g.dispose();
    ImageIO.write(image, "JPEG", response.getOutputStream());
}
    public void destroy() {
    super.destroy();
}

public void init() throws ServletException {
    super.init();
}

}

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