java web生成验证码

//生成验证码后台

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

import javax.imageio.ImageIO;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import net.hp.es.adm.healthcare.rphcp.application.portal.php.common.base.BaseController;

import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;

@Controller
@RequestMapping("/")
public class ValidateCode extends BaseController{
//验证码图片的宽度
    private int width = 100;
    //验证码图片的高度
    private int height = 25;
    //验证码字符个数
    private int codeCount = 4;
    private int x = 0;
    //字体高度
    private int fontHeight;
    private int codeY=0;

/**
     * 生成验证码
     *
     *   void
* @throws IOException
     * @throws
     * @2012-12-14 上午10:59:48
     */
    @RequestMapping(value="validate",method=RequestMethod.GET)
public void validate(HttpServletResponse response,HttpServletRequest request) throws Exception{
    session.removeAttribute("validateCode");//删除上一次验证码
     x = width / (codeCount + 1);
        fontHeight = height - 2;
        codeY = height - 4;
        //
     char[] codeSequence = { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J',
             'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W',
             'X', 'Y', 'Z', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
  //定义图像buffer
        BufferedImage buffImg = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);
        Graphics2D g = buffImg.createGraphics();
        //创建一个随机数生成器类
        Random random = new Random();
        //将图像填充为白色
        g.setColor(Color.white);
        g.fillRect(0, 0, width, height);
        //创建字体，字体的大小应该根据图片的高度来定
        Font font = new Font("Fixedsys", Font.PLAIN, fontHeight);
        //设置字体
        g.setFont(font);
        //画边框
        g.setColor(Color.BLACK);
        g.drawRect(0, 0, width - 1, height - 1);
        //随机产生160条干扰线，使图象中的认证码不易被其它程序探测到
        g.setColor(Color.BLACK);
        for (int i = 0; i < 20; i++) {
            int x = random.nextInt(width);
            int y = random.nextInt(height);
            int xl = random.nextInt(12);
            int yl = random.nextInt(12);
            g.drawLine(x, y, x - xl, y - yl);
        }
        //randomCode用于保存随机产生的验证码，以便用户登录后进行验证
        StringBuffer randomCode = new StringBuffer();
        int red = 0, green = 0, blue = 0;
        //随机产生4个数字的验证码
        for (int i = 0; i < 4; i++) {
            //得到随机产生的验证码数字
            String strRand = String.valueOf(codeSequence[random.nextInt(35)]);
            //产生随机的颜色分量来构造颜色值，这样输出的每位数字的颜色值都将不同
            red = random.nextInt(255);
            green = random.nextInt(255);
            blue = random.nextInt(255);
            //用随机产生的颜色将验证码绘制到图像中
            g.setColor(new Color(red, green, blue));
            g.drawString(strRand, (i + 1) * x, codeY);
            //将产生的四个随机数组合在一起
            randomCode.append(strRand);
        }
        //将四位数字的验证码保存到Session中
        session.setAttribute("validateCode", randomCode.toString());
        //禁止图像缓存
        response.setHeader("Pragma", "no-cache");
        response.setHeader("Cache-Control", "no-cache");
        response.setDateHeader("Expires", 0);
        response.setContentType("image/jpeg");
        //将图像输出到Servlet输出流中
        ServletOutputStream sos = response.getOutputStream();
        ImageIO.write(buffImg, "jpeg", sos);
        sos.close();
    }
}

//验证码前台

java web生成验证码

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