Jsp验证码

 

 

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>

<%@page import="java.awt.image.BufferedImage"%>

<%@page import="java.awt.Graphics2D"%>

<%@page import="java.awt.Color"%>

<%@page import="java.awt.Font"%>

<%@page import="javax.imageio.ImageIO"%>

 

<%

    int width = 60;

    int height = 20;

    // 创建具有可访问图像数据缓冲区的Image

    BufferedImage buffImg = new BufferedImage(width, height,

            BufferedImage.TYPE_INT_RGB);

    Graphics2D g = buffImg.createGraphics();

   

    // 创建一个随机数生成器

    Random random = new Random();

   

    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("Times New Roman", Font.PLAIN, 18);

    // 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

    g.setColor(Color.LIGHT_GRAY);

    for (int i = 0; i < 160; i++) {

        int x = random.nextInt(width);

        int y = random.nextInt(height);

        int x1 = random.nextInt(12);

        int y1 = random.nextInt(12);

        g.drawLine(x, y, x + x1, y + y1);

    }

   

    // randomCode 用于保存随机产生的验证码

    StringBuffer randomCode = new StringBuffer();

    int red = 0, green = 0, blue = 0;

   

    // 随机产生4位数字的验证码

    for (int i = 0; i < 4; i++) {

        // 得到随机产生的验证码数字

        String strRand = String.valueOf(random.nextInt(10));

   

        // 产生随机的颜色分量来构造颜色值

        red = random.nextInt(110);

        green = random.nextInt(50);

        blue = random.nextInt(50);

   

        // 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, 13 * i + 6, 16);

   

        randomCode.append(strRand);

    }

   

    // 将四位数字的验证码保存到session中

    //HttpSession session = request.getSession();

    session.setAttribute("randomCode", 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();

    //sos = null;

    out.clear();

    out = pageContext.pushBody();

%>