课程名称：三小时轻松掌握常用验证码制作
课程章节：第2章 随机字符串验证码
主讲老师：十方上下
课程内容：
今天学习的内容包括：
什么是随机字符串验证码
使用java实现随机字符串验证码
升级及验证随机字符串验证码
使用jQuery实现随机字符串验证码
课程收获：
我的环境是 myeclipse 2020.5.18 javaee 6.0 jstl 1.21 tomcat 8.5
包 原生js 实现随机字符串验证码函数的封装
package com.pxy.cha01;import java.awt.BasicStroke;import java.awt.Color;import java.awt.Font;import java.awt.Graphics2D;import java.awt.image.BufferedImage;import java.io.IOException;import java.util.Random;import javax.imageio.ImageIO;import javax.servlet.ServletException;import javax.servlet.ServletOutputStream;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;/** * Servlet implementation class NewCode */@WebServlet("/NewCode")public class NewCode extends HttpServlet { //private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */// public NewCode() {// super();// // TODO Auto-generated constructor stub// } private Random random=new Random(); private int width=80;//宽度 private int height=30;//高度 private int fontsize=12; private String str="0123456789abcdef"; //生成最少4个随字符串 private String randCode(int len){ if(len<4) { len=4; } //改变画布尺寸 width=5+fontsize*len; String code=""; for (int i = 0; i < len; i++) { code+=str.charAt(random.nextInt(str.length())); } return code; } //返回随机颜色的方法 private Color randColor(){ int r=random.nextInt(256); int g=random.nextInt(256); int b=random.nextInt(256); return new Color(r,g,b); } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); //1.创建画板 BufferedImage img=new BufferedImage(width, height,BufferedImage.TYPE_INT_RGB); //2.创建画笔 Graphics2D pen=(Graphics2D)img.getGraphics(); //3.生成随机内容 //String code="1234"; String code=randCode(4); request.getSession().setAttribute("valiCode", code); //4.绘制内容 //4.1设置绘制区域 pen.fillRect(0, 0, width, height); //4.2设置字体 pen.setFont(new Font("微软雅黑",Font.BOLD,fontsize)); //4.3按顺序逐个绘制字符 for (int i = 0; i <code.length(); i++) { pen.setColor(randColor()); pen.drawString(code.charAt(i)+"", 5+i*fontsize,(fontsize+height)/2); } //4.4绘制噪音线 for (int i = 0; i < 2; i++) { pen.setColor(randColor()); pen.setStroke(new BasicStroke(3)); pen.drawLine(random.nextInt(width/2),random.nextInt(height), random.nextInt(width),random.nextInt(height)); } //5.存为图片并发送 ServletOutputStream out=response.getOutputStream(); ImageIO.write(img,"png", out); out.flush(); out.close(); } protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // }}
<script type="text/javascript"> var valicode; function changeCode() { var cvs = document.getElementById('cvs'); valicode = drawcode(cvs); } function valiCode() { var code=document.getElementById("inCode").value; if(code.toLowerCase()==valicode.toLowerCase()){ return true; }else{ document.getElementById('err').innerHTML="输入的验证码错误"; changeCode(); return false; } } window.onload=changeCode; </script>
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