验证码生成

package com.hpe.servlet;import java.awt.Color;import java.awt.Font;import java.awt.Graphics;import java.awt.image.BufferedImage;import java.io.IOException;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;@WebServlet("/ValidateCodeServlet")public class ValidateCodeServlet extends HttpServlet {    private static final long serialVersionUID = 1L;    public ValidateCodeServlet() {        super();    }    protected void doGet(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        doPost(request, response);    }    protected void doPost(HttpServletRequest request, HttpServletResponse response)            throws ServletException, IOException {        // 响应头信息        response.setHeader("Pragma", "No-Cache");        response.setHeader("Cache-Control", "no-cache");        response.setDateHeader("Expries", 0);        // 随机数生成类        Random random = new Random();        // 定义验证码的位数        int size = 5;        // 定义变量保存生成的验证码        String vCode = "";        char c;        // 产生验证码        for (int i = 0; i < size; i++) {            // 产生一个26以内的随机整数            int number = random.nextInt(26);            // 如果生成的是偶数，则随机生成一个数字            if (number % 2 == 0) {                c = (char) ('0' + (char) ((int) (Math.random() * 10)));                // 如果生成的是奇数，则随机生成一个字母            } else {                c = (char) ((char) ((int) (Math.random() * 26)) + 'A');            }            vCode = vCode + c;        }        // 保存生成的5位验证码        request.getSession().setAttribute("vCode", vCode);        // 验证码图片的生成        // 定义图片的宽度和高度        int width = (int) Math.ceil(size * 20);        int height = 50;        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);        // 获取图片的上下文        Graphics gr = image.getGraphics();        // 设定图片背景颜色        gr.setColor(Color.WHITE);        gr.fillRect(0, 0, width, height);        // 设定图片边框        gr.setColor(Color.GRAY);        gr.drawRect(0, 0, width - 1, height - 1);        // 画十条干扰线        for (int i = 0; i < 5; i++) {            int x1 = random.nextInt(width);            int y1 = random.nextInt(height);            int x2 = random.nextInt(width);            int y2 = random.nextInt(height);            gr.setColor(randomColor());            gr.drawLine(x1, y1, x2, y2);        }        // 设置字体，画验证码        gr.setColor(randomColor());        gr.setFont(randomFont());        gr.drawString(vCode, 10, 22);        // 图像生效        gr.dispose();        // 输出到页面        ImageIO.write(image, "JPEG", response.getOutputStream());    }    // 生成随机的颜色    private Color randomColor() {        int red = r.nextInt(150);        int green = r.nextInt(150);        int blue = r.nextInt(150);        return new Color(red, green, blue);    }    private String[] fontNames = { "宋体", "华文楷体", "黑体", "微软雅黑", "楷体_GB2312" };    private Random r = new Random();    // 生成随机的字体    private Font randomFont() {        int index = r.nextInt(fontNames.length);        String fontName = fontNames[index];// 生成随机的字体名称        int style = r.nextInt(4);        int size = r.nextInt(3) + 24; // 生成随机字号, 24 ~ 28        return new Font(fontName, style, size);    }}