JSP 验证码

 

<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>
<%@ page contentType="p_w_picpath/jpeg"
    import="java.awt.*,java.awt.p_w_picpath.*,java.util.*,javax.p_w_picpathio.*"%>

<%!
    Color getRandColor(int cc, int bb)

    {

        Random random = new Random();

        if (cc > 255)
            cc = 255;

        if (bb > 255)
            bb = 255;

        int r = cc + random.nextInt(bb - cc);

        int g = cc + random.nextInt(bb - cc);

        int b = cc + random.nextInt(bb - cc);

        return new Color(r, g, b);

    } //获取随机颜色
%>

<%
    response.setHeader("Pragma", "No-cache");

    response.setHeader("Cache-Control", "no-cache");

    response.setDateHeader("Expires", 0);

    int width = 80; //定义验证码图片的长度

    int height = 30; //定义验证码图片的宽度

    BufferedImage p_w_picpath = new BufferedImage(width, height,
            BufferedImage.TYPE_INT_RGB);

    Graphics g = p_w_picpath.getGraphics();

    Random random = new Random();

    g.setColor(getRandColor(200, 250));

    g.fillRect(0, 0, width, height);

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

    //定义字体形式

    g.setColor(getRandColor(160, 200));

    for (int i = 0; i < 155; i++)

    {

        int i_x = random.nextInt(width);

        int i_y = random.nextInt(height);

        int i_xl = random.nextInt(12);

        int i_yl = random.nextInt(12);

        g.drawLine(i_x, i_y, i_x + i_xl, i_y + i_yl);

    }

    //用线条画背景

    String s_Rand = "";

    for (int i = 0; i < 4; i++)

    {

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

        s_Rand += rand;

        g.setColor(new Color(20 + random.nextInt(110), 20 + random
                .nextInt(110), 20 + random.nextInt(110)));

        g.drawString(rand, 13 * i + 6, 16);

    }

    //产生4位随机码

    session.setAttribute("rand", s_Rand);

    //将验证码存入Session中

    g.dispose();

    ImageIO.write(p_w_picpath, "JPEG", response.getOutputStream());

    //输出验证图片

    out.clear();

    out = pageContext.pushBody();
%>