生成检验码的两种方式

来源：互联网发布：消费者网络投诉编辑：程序博客网时间：2024/05/19 22:45

一、Servlet + web.xml

1、Servlet 代码：

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.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;/** * 验证码 *  * @author zcq * @version 1.0 *  *          变更履历： *          v1.0 2017-6-26 zcq 初版 */public class CheckCode extends HttpServlet {    private static final long serialVersionUID = 1L;    /**     * 获取校验码     *      * @author zcq     * @param req     * @param res     * @throws IOException     * @throws ServletException     */    public void doGet(HttpServletRequest req, HttpServletResponse res) throws IOException, ServletException {        // 设置页面不缓存        res.setContentType("images/jpeg");        res.setHeader("Pragma", "No-cache");        res.setHeader("Cache-Control", "no-cache");        res.setDateHeader("Expires", 0);        HttpSession session = req.getSession(true);        // 在内存中创建图象        int width = 160;        // 在内存中创建图象        int height = 80;        BufferedImage image = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);        // 获取图形上下文        Graphics g = image.getGraphics();        // 生成随机类        Random random = new Random();        // 设定背景色 -白色        g.setColor(new Color(255, 255, 255));        g.fillRect(0, 0, width, height);        // 设定字体        g.setFont(new Font("Times New Roman", Font.PLAIN, 60));        // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到        g.setColor(getRandColor(160, 200));        for (int i = 0; i < 4; i++) {            int x = random.nextInt(width);            int y = random.nextInt(height);            int xl = random.nextInt(30);            int yl = random.nextInt(30);            g.drawLine(x, y, x + xl, y + yl);        }        // 取随机产生的认证码(4位数字)        String[] code = {"a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "m", "n", "p", "q", "r", "s", "t", "u",                "v",                "w", "x", "y", "z", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F", "G", "H",                "J", "K",                "L", "N", "P", "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"};        // 数组长度        int length = code.length;        String sRand = "";        for (int i = 0; i < 4; i++) {            // String rand=String.valueOf(random.nextInt(10)); //原来方法这个是产生数字的0-9            // sRand+=rand;            int start = random.nextInt(length);            String rand = code[start];            sRand += rand;            // 将认证码显示到图象中 - 红色            g.setColor(new Color(220, 20, 60)); // 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成            g.drawString(rand, (30 * i) + 15, 60);        }        // 将认证码存入SESSION        session.setAttribute("rand", sRand);        // 图象生效        g.dispose();        // 输出图象到页面        ImageIO.write(image, "JPEG", res.getOutputStream());    }    private Color getRandColor(int fc, int bc) {        // 给定范围获得随机颜色        Random random = new Random();        if (fc > 255) {            fc = 255;        }        if (bc > 255) {            bc = 255;        }        int r = fc + random.nextInt(bc - fc);        int g = fc + random.nextInt(bc - fc);        int b = fc + random.nextInt(bc - fc);        return new Color(r, g, b);    }}

2、web.xml 配置：

<!-- 检验码 --><servlet><servlet-name>CheckCode</servlet-name><servlet-class>com.mnt.preg.web.controller.CheckCode</servlet-class></servlet><servlet-mapping><servlet-name>CheckCode</servlet-name><url-pattern>/CheckCode</url-pattern></servlet-mapping>

3、jsp页面：

function changeimg(){var myimg = document.getElementById("randimg"); now = new Date(); myimg.src="page/rand.jsp?code="+now.getTime();}//提交$(document).ready(function(){        changeimg();});<img id="randimg" onclick="changeimg();" width="80" height="45" />

二、rand.jsp

<%@page pageEncoding="UTF-8"  language="java" contentType="image/jpeg" import="java.awt.*,java.awt.image.*,java.util.*,javax.imageio.*" %><%@ page import="com.mnt.preg.web.constants.SessionConstant"%><%!Color getRandColor(int fc,int bc){//给定范围获得随机颜色        Random random = new Random();        if(fc>255) fc=255;        if(bc>255) bc=255;        int r=fc+random.nextInt(bc-fc);        int g=fc+random.nextInt(bc-fc);        int b=fc+random.nextInt(bc-fc);        return new Color(r,g,b);        }%><%       // 设置页面不缓存        response.setContentType("images/jpeg");        response.setHeader("Pragma", "No-cache");        response.setHeader("Cache-Control", "no-cache");        response.setDateHeader("Expires", 0);        // 在内存中创建图象        int width = 105;        // 在内存中创建图象        int height = 46;        BufferedImage image = new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB);        // 获取图形上下文        Graphics2D  g = image.createGraphics();        // 生成随机类        Random random = new Random();        // 设定背景色 -白色        g.setColor(new Color(255,255,255));        g.fillRect(0, 0, width, height);        // 设定字体        g.setFont(new Font("Times New Roman", Font.PLAIN, 38));        // 随机产生155条干扰线，使图象中的认证码不易被其它程序探测到        g.setColor(getRandColor(160, 200));        for (int i = 0; i < 4; i++) {            int x = random.nextInt(width);            int y = random.nextInt(height);            int xl = random.nextInt(30);            int yl = random.nextInt(30);            g.drawLine(x, y, x + xl, y + yl);        }        // 取随机产生的认证码(4位数字)        String[] code = {                "a", "b", "c", "d", "e", "f", "g", "h", "i", "j", "k", "m",                "n", "p", "q", "r", "s", "t", "u", "v", "w", "x", "y", "z",                "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C",                "D", "E", "F", "G", "H", "J", "K", "L", "N",  "P",                "Q", "R", "S", "T", "U", "V", "W", "X", "Y", "Z"            };        // 数组长度        int length = code.length;        String sRand = "";        for (int i = 0; i < 4; i++) {            // String rand=String.valueOf(random.nextInt(10)); //原来方法这个是产生数字的0-9            // sRand+=rand;            int start = random.nextInt(length);            String rand = code[start];            sRand += rand;            // 将认证码显示到图象中 - 红色            g.setColor(new Color(220,20,60)); // 调用函数出来的颜色相同，可能是因为种子太接近，所以只能直接生成            g.drawString(rand, (23 * i) + 6, 32);        }        // 将认证码存入SESSION        session.setAttribute(SessionConstant.LOGIN_USER_RAND_CODE, sRand);        // 图象生效        g.dispose();        // 输出图象到页面        ImageIO.write(image, "JPEG", response.getOutputStream());//下边两行是防止抛出getOutputStream() has already been called for this response异常的out.clear();out = pageContext.pushBody();%>

jsp页面：

function changeimg(){var myimg = document.getElementById("randimg"); now = new Date(); myimg.src="page/rand.jsp?code="+now.getTime();}<img id="randimg" src="page/rand.jsp" onclick="changeimg();" width="80" height="45" />

阅读全文

0 0