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Jsp servlet驗證碼工具類分享
昨晚在csdn看到一位前輩寫一個ajax+servlet+jsp驗證，頓時心血來潮，在閱讀前輩的代碼下我親手體驗一下，做了一個驗證碼生成工具類，以供大家做個參考。
1、添加VeriyCodeUtils類生成驗證碼圖像
package com.servlet; import java.awt.Color; import java.awt.Font; import java.awt.Graphics2D; import java.awt.image.BufferedImage; import java.io.OutputStream; import java.util.Random; import javax.imageio.ImageIO; /** * * @author hubiao * 驗證碼生成器 * 用到API * BufferedImage 創建一個圖像 * Graphics2D 繪制 * fillRect(x,y,width,height);背景 * font()字體 * drawRect();邊框 * drawLine();線 * drwaString:圖像數據 * ImageIO 生成圖像 */ public class VeriyCodeUtils { /** * @param output 保存驗證圖像的流 * @return 驗證碼 */ public static String newVeriyCode(OutputStream output) { int width = 90; int height = 40; int codeCount = 5; 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" }; //創建圖像對象,8位RGB BufferedImage buffered = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB); //通過Crapahices來繪制圖像到BufferedImage中 Graphics2D gra = buffered.createGraphics(); //設置圖片背景：白色 gra.setColor(Color.WHITE); gra.fillRect(0, 0, width, height); //設置字體,字體大小根據圖片高度決定 gra.setFont(new Font("Fixedsys",Font.PLAIN,height-2)); //設置邊框：黑色,1cm gra.setColor(Color.BLACK); gra.drawRect(0, 0, width-1, height-1); //生成10條黑色干擾線 gra.setColor(Color.BLACK); Random ran = new Random(); for(int i = 0; i < 70;i++) { int x = ran.nextInt(255); int y = ran.nextInt(255); int x1 = ran.nextInt(255); int y1 = ran.nextInt(255); gra.drawLine(x, y,x+x1, y+y1);//畫直線 } //生成驗證碼 StringBuffer sb = new StringBuffer(); int r = 0,g = 0,b = 0; for(int i = 0; i < codeCount; i++) { String strRand = String.valueOf(codeSequence[ran.nextInt(codeSequence.length)]); //對每位驗證碼都生成不同的顏色，增加識別系統難度 r = ran.nextInt(255); g = ran.nextInt(255); b = ran.nextInt(255); gra.setColor(new Color(r, g, b)); gra.drawString(strRand, (i+1)*13, height-4); sb.append(strRand); } try { ImageIO.write(buffered, "jpeg", output); } catch (Exception e) { throw new RuntimeException(e); } return sb.toString(); } } 2、servlet使用驗證碼
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { //禁止圖像緩存 resp.setHeader("Pragma", "no-cache"); resp.setHeader("Cache-Control", "no-cache"); resp.setDateHeader("Expires", 0); resp.setContentType("image/jpeg"); //生成驗證碼圖像 String veriyCode = VeriyCodeUtils.newVeriyCode(resp.getOutputStream()); //將驗證碼保存到session中 HttpSession session = req.getSession(); session.setAttribute("validateCode", veriyCode); } 3、JSP頁面使用驗證碼
</head> <script type="text/javascript"> function createCode() { var t = new Date().getTime();//防止頁面緩存，使用時間搓 var srcImg = document.getElementById("srcImg"); srcImg.src="/ImgVeifyWeb/vity.do?"+t; } </script> <body> <h1>${requestScope.code}</h1> <img id="srcImg" src="<c:url value="/vity.do"></c:url>" /> #這里使用直接讓img訪問servlet,通過response響應一個圖像流 <a href="##" rel="external nofollow" id="codeId" onclick="createCode()">換一張</a> <form action="<c:url value="/hello.do"></c:url>" method="post"> <input type="text" name="codeVify"/> <input type="submit" value="提交"/> </form> </body> 4、校驗驗證碼
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { HttpSession session = req.getSession(); Object validateCode = session.getAttribute("validateCode"); System.out.println(validateCode); String codeVify = req.getParameter("codeVify"); if(codeVify==null || codeVify.equals("")) { req.setAttribute("code","驗證證不能為空"); req.getRequestDispatcher("/index.jsp").forward(req, resp); return; }else if(!validateCode.toString().equalsIgnoreCase(codeVify)) { req.setAttribute("code","驗證證錯誤"); req.getRequestDispatcher("/index.jsp").forward(req, resp); return; } System.out.println("下面開始 做其他業務操作...."); } 校驗圖如下：
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