生成图片验证码
package cn.itcast.estore.web.servlet; import java.awt.Color; import java.awt.Font; import java.awt.Graphics; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.BufferedReader; import java.io.FileReader; import java.io.IOException; import java.util.ArrayList; import java.util.List; 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; /** * 验证码生成程序 * * * */ @WebServlet("/CheckImgServlet") public class CheckImgServlet extends HttpServlet { // 集合中保存所有成语 private List<String> words = new ArrayList<String>(); @Override public void init() throws ServletException { // 初始化阶段，读取new_words.txt // web工程中读取 文件，必须使用绝对磁盘路径 String path = getServletContext().getRealPath("/WEB-INF/new_words.txt"); try { BufferedReader reader = new BufferedReader(new FileReader(path)); String line; while ((line = reader.readLine()) != null) { words.add(line); } reader.close(); } catch (IOException e) { e.printStackTrace(); } } public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 禁止缓存 // response.setHeader("Cache-Control", "no-cache"); // response.setHeader("Pragma", "no-cache"); // response.setDateHeader("Expires", -1); int width = 120; int height = 30; // 步骤一 绘制一张内存中图片 BufferedImage bufferedImage = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 步骤二 图片绘制背景颜色 ---通过绘图对象 Graphics graphics = bufferedImage.getGraphics();// 得到画图对象 --- 画笔 // 绘制任何图形之前 都必须指定一个颜色 graphics.setColor(getRandColor(200, 250)); graphics.fillRect(0, 0, width, height); // 步骤三 绘制边框 graphics.setColor(Color.WHITE); graphics.drawRect(0, 0, width - 1, height - 1); // 步骤四 四个随机数字 Graphics2D graphics2d = (Graphics2D) graphics; // 设置输出字体 graphics2d.setFont(new Font("宋体", Font.BOLD, 18)); Random random = new Random();// 生成随机数 int index = random.nextInt(words.size()); String word = words.get(index);// 获得成语 // 定义x坐标 int x = 10; for (int i = 0; i < word.length(); i++) { // 随机颜色 graphics2d.setColor(new Color(20 + random.nextInt(110), 20 + random .nextInt(110), 20 + random.nextInt(110))); // 旋转 -30 --- 30度 int jiaodu = random.nextInt(60) - 30; // 换算弧度 double theta = jiaodu * Math.PI / 180; // 获得字母数字 char c = word.charAt(i); // 将c 输出到图片 graphics2d.rotate(theta, x, 20); graphics2d.drawString(String.valueOf(c), x, 20); graphics2d.rotate(-theta, x, 20); x += 30; } // 将验证码内容保存session request.getSession().setAttribute("checkcode_session", word); // 步骤五 绘制干扰线 graphics.setColor(getRandColor(160, 200)); int x1; int x2; int y1; int y2; for (int i = 0; i < 30; i++) { x1 = random.nextInt(width); x2 = random.nextInt(12); y1 = random.nextInt(height); y2 = random.nextInt(12); graphics.drawLine(x1, y1, x1 + x2, x2 + y2); } // 将上面图片输出到浏览器 ImageIO graphics.dispose();// 释放资源 ImageIO.write(bufferedImage, "jpg", response.getOutputStream()); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { doGet(request, response); } /** * 取其某一范围的color * * @param fc * int 范围参数1 * @param bc * int 范围参数2 * @return Color */ private Color getRandColor(int fc, int bc) { // 取其随机颜色 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); } }
在界面获取时，
<img title="" alt="" src="CheckImgServlet" /> <!--将servlet的地址输入进来-->
即可获取
代码2
package com.mhss.servlet; 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.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; /** * 通过二维画图 生成验证码图片 * @author 梦幻逝水 * */ public class ValidateServlet extends HttpServlet { /** * */ private static final long serialVersionUID = 1L; /** 验证码图片的宽度 */ private int width = 150; /** 验证码图片的高度 */ private int height = 55; /** 验证码字符个数 */ private int codeCount = 4; // 字符间距 private int x = 0; // 字体高度 private int fontHeight; private int codeY; char[] codeSequence = { \'A\', \'B\', \'C\', \'D\', \'E\', \'F\', \'G\', \'H\', \'I\', \'J\', \'K\', \'L\', \'M\', \'N\', \'O\', \'P\', \'Q\', \'R\', \'S\', \'T\', \'U\', \'V\', \'W\', \'X\', \'Y\', \'Z\', \'0\', \'1\', \'2\', \'3\', \'4\', \'5\', \'6\', \'7\', \'8\', \'9\' }; public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.service(request, response); } public void init() { // 宽度 String strWidth = this.getInitParameter("width"); // 高度 String strHeight = this.getInitParameter("height"); // 字符个数 String strCodeCount = this.getInitParameter("codeCount"); if (strWidth != null && strWidth.length() != 0) { width = Integer.parseInt(strWidth); } if (strHeight != null && strHeight.length() != 0) { height = Integer.parseInt(strHeight); } if (strCodeCount != null && strCodeCount.length() != 0) { codeCount = Integer.parseInt(strCodeCount); } // 计算验证码在图片中位置 x = width / (codeCount + 1); fontHeight = height - 2; codeY = height - 4; } /** * 产生随机码图片 */ public void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // 产生图片 BufferedImage bi = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); // 网图片中加载图片的工具 Graphics2D g = bi.createGraphics(); // 添加背景 g.setColor(Color.WHITE); g.fillRect(0, 0, width, height); // 创建字体 Font font = new Font("Fixedsys", Font.PLAIN | Font.BOLD, fontHeight); // 设置字体 g.setFont(font); // 画边框 g.setColor(Color.black); g.drawRect(0, 0, width - 1, height - 1); // 画干扰线 Random random = new Random(); g.setColor(Color.PINK); for (int i = 0; i < 100; i++) { int x = random.nextInt(width); int y = random.nextInt(height); int xl = random.nextInt(12); int yl = random.nextInt(12); g.drawLine(x, y, x + xl, y + yl); } StringBuffer sbnumber = new StringBuffer(); // 生成随机码 for (int i = 0; i < this.codeCount; i++) { String strRand = String.valueOf(codeSequence[random.nextInt(36)]); // 随机产生颜色分量来创建颜色 int red = random.nextInt(255); int green = random.nextInt(255); int blue = random.nextInt(255); // g.setColor(new Color(red, green, blue)); g.drawString(strRand, (i + 1) * x - 6, codeY); // 把每次生成的验证码放在缓冲区 sbnumber.append(strRand); } // 把生成的验证码放在session中 request.getSession().setAttribute("sbnumber", sbnumber.toString()); // 把最终生成 图片 响应到页面去 response.setContentType("image/jpeg"); ServletOutputStream sos = response.getOutputStream(); // 把图片 发送出去 ImageIO.write(bi, "jpeg", sos); sos.close(); } }
页面引用时 同样通过
<img title="" alt="" src="CheckImgServlet" /> <!--将servlet的地址输入进来-->
获取:页面代码如下
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%> <% String path = request.getContextPath(); String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/"; %> <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> <html> <head> <base href="<%=basePath%>"> <title>My JSP \'index.jsp\' starting page</title> <meta http-equiv="pragma" content="no-cache"> <meta http-equiv="cache-control" content="no-cache"> <meta http-equiv="expires" content="0"> <meta http-equiv="keywords" content="keyword1,keyword2,keyword3"> <meta http-equiv="description" content="This is my page"> <!-- <link rel="stylesheet" type="text/css" href="styles.css"> --> <script type="text/javascript"> function newCode(){ var today = new Date(); document.getElementById("imgNumber").src="ValidateServlet?tm="+today.getTime(); } </script> </head> <body> <form action=""> 验证码： <input type="text" name="text" /> <img src="ValidateServlet" id="imgNumber"/> <a href="javascript:newCode()">看不清,换一张</a> </form> <br/> </body> </html>
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