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手動(dòng)制作java的驗(yàn)證碼,具體內(nèi)容如下
Web應(yīng)用驗(yàn)證碼的組成:
(1)輸入框
(2)顯示驗(yàn)證碼的圖片
驗(yàn)證碼的制作流程:
生成驗(yàn)證碼的容器使用 j2ee的servlet
生成圖片需要的類:
(1) BufferedImage 圖像數(shù)據(jù)緩沖區(qū)
(2)Graphic繪制圖片
(3)Color獲取顏色
(4)Random生成隨機(jī)數(shù)
(5)ImageIO輸入圖片
具體實(shí)現(xiàn)流程:
(1)定義一個(gè)Servlet,用于生成驗(yàn)證碼
(2)定已BufferedImage對(duì)象,主要作用就是制作一個(gè)圖片緩沖區(qū),作為圖片的一個(gè)臨時(shí)容器。
(3)獲得Graphic對(duì)象,畫(huà)圖的“背景”,理解為"畫(huà)布"
(4)通過(guò)Random生成隨機(jī)數(shù),來(lái)制作驗(yàn)證信息
(5)通過(guò)Graphic操作,進(jìn)行具體畫(huà)圖
(6)信息存至session中
(7)使用ImageIO輸出生成的圖片,通過(guò)設(shè)置ImageIO的 write()方法中的out參數(shù),response.getOutputStream(),將圖片傳至前臺(tái)
(8)制作驗(yàn)證用的servlet,提取session中的數(shù)據(jù)進(jìn)行驗(yàn)證(這里采用ajax異步方法)
具體代碼實(shí)現(xiàn)(Web端驗(yàn)證碼實(shí)例)
<html> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <title>java驗(yàn)證碼</title> <script src="https://apps.bdimg.com/libs/jquery/2.1.4/jquery.min.js"></script> </head> <body> 驗(yàn)證碼輸入:<input type="text" name="checkcode"> <img id="codeimg" alt="驗(yàn)證碼" src="ImageServlet"> <a href="javascript:reloadCode();">看不出清楚?</a><br/> <input type="submit" value="提交"> <div id="info" ></div> <script type="text/javascript"> $(function(){ //ajax異步傳驗(yàn)證碼至后臺(tái) $("input[type=submit]").click(function(){ $.post("CheckCode", {"code":$("input[name=checkcode]").val()}, function(data,textStatus) { console.log(textStatus); $("#info").html(data); },"text"); }); }) //js刷新,重新請(qǐng)求頁(yè)面,獲得新的驗(yàn)證碼 function reloadCode(){ var time = new Date().getTime();//創(chuàng)建不同的時(shí)間 $("#codeimg").attr("src","ImageServlet?time="+time);//因?yàn)闀r(shí)間參數(shù)不同,請(qǐng)求重新 } </script> </body> </html>
ImageServlet類(驗(yàn)證碼生成部分)
@WebServlet("/ImageServlet") public class ImageServlet extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public ImageServlet() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub BufferedImage bimg = new BufferedImage(68, 22, BufferedImage.TYPE_INT_RGB); Graphics g = bimg.getGraphics(); Color color = new Color(200,151,255);//顏色生成 g.setColor(color); g.fillRect(0, 0, 68, 22); char[] ch="ABCDEFGHJIKLMNOPQRSTUVWXYZ0123456789".toCharArray();//獲得一個(gè)含有字母和數(shù)字的數(shù)組,后續(xù)隨機(jī)從中獲取字符 Random random = new Random(); //創(chuàng)建隨機(jī)數(shù) int len = ch.length,index; StringBuffer sBuffer = new StringBuffer(); //循環(huán)產(chǎn)生4個(gè)隨機(jī)字符 for(int i = 0 ;i<4;i++) { index = random.nextInt(len);//產(chǎn)生隨機(jī)字母與數(shù)字 g.setColor(new Color(random.nextInt(88),random.nextInt(120),random.nextInt(90)));//創(chuàng)建隨機(jī)顏色 g.drawString(ch[index]+"", (i)*15+3, 18); sBuffer.append(ch[index]);//將隨機(jī)獲取的字符放置緩沖串中 } request.getSession().setAttribute("newCode", sBuffer.toString());//存至session便于后續(xù)驗(yàn)證 ImageIO.write(bimg, "JPG", response.getOutputStream());//通過(guò)ImageIO輸出圖片,并傳至前臺(tái) } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }
CheckCode(驗(yàn)證碼驗(yàn)證servlet)
@WebServlet("/CheckCode") public class CheckCode extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public CheckCode() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub response.setCharacterEncoding("utf-8"); String code = request.getParameter("code").toUpperCase();//獲取傳來(lái)驗(yàn)證碼并進(jìn)行大小寫(xiě)轉(zhuǎn)換 String result=null; if(request.getSession().getAttribute("newCode").equals(code)) { result="驗(yàn)證成功!"; response.getWriter().append(result); } else { result="驗(yàn)證碼錯(cuò)誤!"; response.getWriter().append(result); } } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); } }
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