仿腾讯随机验证图片

一个类和一个JSP

Java类代码：

package icewee.image;

import java.awt.BasicStroke;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics2D;
import java.awt.RenderingHints;
import java.awt.geom.Line2D;
import java.awt.image.BufferedImage;
import java.util.Random;

public class TokenUtil {
    private static final String base = "23456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefhijklmnpqrstuvwxyz";
    private static final int length = base.length();

    public static BufferedImage createTokenImage(int width, int height,
            String randomCode) {
        BufferedImage image = new BufferedImage(width, height,
                BufferedImage.TYPE_INT_RGB);
        Graphics2D g = image.createGraphics();
        Random random = new Random();
        g.setColor(new Color(230, 230, 250)); // 设置背景色
        g.fillRect(0, 0, width, height); // 填充背景
        g.setColor(Color.BLACK);
        // 绘制边缘
        g.drawRect(-1, -1, width + 1, height + 1);
        g.setColor(Color.GRAY);
        // 设置字体,随机选择字体,暂设置8种字体
        Font font = new Font((new String[] { "Arial", "Arial Black",
                "Arial Italic", "Courier New", "Courier New Bold Italic",
                "Courier New Italic", "Franklin Gothic Medium",
                "Franklin Gothic Medium Italic" })[random.nextInt(8)],
                Font.PLAIN, 30);
        // g.setStroke(new BasicStroke((float)(Math.random()),
        // BasicStroke.CAP_BUTT, BasicStroke.JOIN_BEVEL));
        g.setFont(font);
        // 定义字体颜色范围
        int red = random.nextInt(160), green = random.nextInt(50), blue = random
                .nextInt(50);
        // 定义一个无干扰线区间和一个起始位置
        int nor = random.nextInt(50), rsta = random.nextInt(131);
        // 绘制干扰正弦曲线 M:曲线平折度, D:Y轴常量 V:X轴焦距
        int M = random.nextInt(15) + 5, D = random.nextInt(23) + 15, V = random
                .nextInt(5) + 1;
        double x = 0.0;
        double y = M * Math.sin(Math.toRadians(V * x)) + D;
        double px, py;
        for (int i = 0; i < 131; i++) {
            px = x + 1;
            py = M * Math.sin(Math.toRadians(V * px)) + D;
            if (rsta < i && i < (rsta + nor))
                g.setColor(new Color(230, 230, 250));
            else
                g.setColor(new Color(red, green, blue));
            // 随机设置像素点宽带(线宽)
            g.setStroke(new BasicStroke((float) (Math.random() + 1.5f)));
            g.draw(new Line2D.Double(x, y, px, py));
            x = px;
            y = py;
        }
        char[] codes = randomCode.toCharArray();
        for (int i = 0; i < codes.length; i++) {
            // 旋转图形
            int degree = (random.nextInt(20) - 10) % 360;
            double ang = degree * 0.0174532925; // 将角度转为弧度
            g.rotate(ang, width / 2, height / 2);
            g.setColor(new Color(red, green, blue));
            g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
                    RenderingHints.VALUE_ANTIALIAS_ON);
            int gr = random.nextInt(8);
            g.drawString(String.valueOf(codes[i]), 24 * i + 10 + gr, 38);
        }
        g.dispose();
        return image;
    }

    public static String createRandomCode(int size, int width, int height) {
        StringBuffer randomCode = new StringBuffer();
        for (int i = 0; i < size; i++) {
            Random random = new Random();
            int start = random.nextInt(length);
            String strRand = base.substring(start, start + 1);
            randomCode.append(strRand);
        }
        return randomCode.toString();
    }
}

JSP页面：

<%@ page contentType="image/jpeg" pageEncoding="GBK"%>
<%@ page import="java.awt.image.BufferedImage" %>
<%@page import="javax.imageio.ImageIO" %>
<%@ page import="com.icesoft.image.TokenUtil" %>

<%
    //设置页面不缓存
    response.setHeader("Pragma", "No-cache");
    response.setHeader("Cache-Control", "no-cache");
    response.setDateHeader("Expires", 0);
    int width = 120, height = 50;
    String randomCode = TokenUtil.createRandomCode(4, width, height);
    System.out.println("生成的随机码：" + randomCode);
    BufferedImage image = TokenUtil.createTokenImage(width, height, randomCode);
    ImageIO.write(image, "JPEG", response.getOutputStream());
    response.flushBuffer();
    out.clear();
    out = pageContext.pushBody();
%>