从零玩转JavaWeb系列7web服务器------用户登陆界面二维码的制作
1.用eclipse工具新建一个Dynamic Web Project工程如下：
2.在Java Resources的src目录下新建一个包，包名称为com.it666.code
3.在com.it666.code包下创建2个Servlet，名字分别为CheckCodeServelt、RegistServlet
CheckCodeServelt代码：
package com.it666.code; 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.annotation.WebServlet; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; @WebServlet("/CheckCodeServlet") public class CheckCodeServlet extends HttpServlet { private static final long serialVersionUID = 1L; // 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/words.txt"); try { BufferedReader reader = new BufferedReader(new FileReader(path)); String line; //把读的成语全部添加到一个集合当中 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 { 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 System.out.println(word); // 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(企业开发当中用) //request.getSession().setAttribute("checkcode_session", word); //把生成的验证码存放到全局域对象当中（一般不会用这种方法） this.getServletContext().setAttribute("checkCode", 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 //将图片写到response.getOutputStream()中 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); } }
RegistServlet代码如下：
package com.it666.code; import java.io.IOException; 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("/RegistServelt") public class RegistServelt extends HttpServlet { private static final long serialVersionUID = 1L; protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //接收请求参数的内容 String code = request.getParameter("code"); System.out.println(code); //将请求的参数内容由ISO8859-1转码成UTF-8 byte[] bytes = code.getBytes("ISO8859-1"); code = new String(bytes,"UTF-8"); System.out.println("code="+code); //获取验证码内容 String name = (String)this.getServletContext().getAttribute("checkCode"); System.out.println("name="+name); //设置缓冲区当中使用的编码 //response.setCharacterEncoding("UTF-8"); //设置缓冲区当中使用的编码、告诉浏览器要用什么字符集来接收响应 response.setContentType("text/html;charset=UTF-8"); //进行匹配并且输出匹配结果 if(name.equals(code)) { response.getWriter().write("验证码 正确"); }else { response.getWriter().write("验证码 错误"); response.setHeader("refresh", "3;url=/26-Servlet/code.html"); } } }
4.在WebContent文件夹的WEB-INF文件夹下面创建web.xml、words.txt。
web.xml代码如下：
<?xml version="1.0" encoding="UTF-8"?> <web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" metadata-complete="false" version="3.0"> <absolute-ordering/> <display-name>web</display-name> <welcome-file-list> <welcome-file>index.html</welcome-file> <welcome-file>index.htm</welcome-file> <welcome-file>index.jsp</welcome-file> </welcome-file-list> </web-app>
words.txt文件主要用于放验证码的文字。如下：
5.在WebContent文件夹下只创建code.html文件（其他文件不用创建）
code.html代码：
<!DOCTYPE html> <html> <head> <meta charset="UTF-8"> <title>code</title> <script type="text/javascript"> function chang(obj) { obj.src = "/26-Servlet/CheckCodeServlet?time=" + new Date().getTime(); } </script> </head> <body> <form action="/26-Servlet/RegistServelt"> <img src="/26-Servlet/CheckCodeServlet" onclick="chang(this)"> <br /> <input type="text" placeholder="请输入验证码..." name ="code"> <br /> <input type="submit" value="注册"> </form> </body> </html>
6.在code.html文件下单机运行即可
以下为eclipse工具测试结果：
1.匹配正确实例：
2.匹配错误实例：
