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package com.lhy.web.servlet;import java.awt.BasicStroke;import java.awt.Color;import java.awt.Font;import java.awt.Graphics2D;import java.awt.image.BufferedImage;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.OutputStream;import java.util.Random;import javax.imageio.ImageIO;public class VerifyCode { private int w = 70;//圖片長(zhǎng) private int h = 35;//圖片寬 private Random r = new Random();//Random類 生成隨機(jī)數(shù) // 列舉驗(yàn)證圖片中驗(yàn)證碼的字體類型 //{"宋體", "華文楷體", "黑體", "華文新魏", "華文隸書(shū)", "微軟雅黑", "楷體_GB2312"} private String[] fontNames = {"宋體", "華文楷體", "黑體", "微軟雅黑", "楷體_GB2312"}; // 驗(yàn)證碼可選字符 private String codes="23456789abcdefghjkmnopqrstuvwxyzABCDEFGHJKMNPQRSTUVWXYZ"; // 背景色 private Color bgColor = new Color(255, 255, 255); // 驗(yàn)證碼上的文本 private String text ; // 生成隨機(jī)的顏色 private Color randomColor () { int red = r.nextInt(150); int green = r.nextInt(150); int blue = r.nextInt(150); return new Color(red, green, blue); } // 生成隨機(jī)的字體 private Font randomFont () { int index = r.nextInt(fontNames.length); String fontName = fontNames[index];//生成隨機(jī)的字體名稱 int style = r.nextInt(4);//生成隨機(jī)的樣式, 0(無(wú)樣式), 1(粗體), 2(斜體), 3(粗體+斜體) int size = r.nextInt(5) + 24; //生成隨機(jī)字號(hào), 24 ~ 28 return new Font(fontName, style, size); } // 畫(huà)干擾線 private void drawLine (BufferedImage image) { int num = 3;//一共畫(huà)3條 Graphics2D g2 = (Graphics2D)image.getGraphics(); for(int i = 0; i < num; i++) {//生成兩個(gè)點(diǎn)的坐標(biāo)，即4個(gè)值 int x1 = r.nextInt(w); int y1 = r.nextInt(h); int x2 = r.nextInt(w); int y2 = r.nextInt(h); g2.setStroke(new BasicStroke(1.5F)); g2.setColor(Color.BLUE); //干擾線是藍(lán)色 g2.drawLine(x1, y1, x2, y2);//畫(huà)線 } } // 隨機(jī)生成一個(gè)字符 private char randomChar () { int index = r.nextInt(codes.length()); return codes.charAt(index); } // 創(chuàng)建BufferedImage private BufferedImage createImage () { //寬，高，圖片的類型 BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB); Graphics2D g2 = (Graphics2D)image.getGraphics(); g2.setColor(this.bgColor); g2.fillRect(0, 0, w, h); return image; } // 返回驗(yàn)證碼圖片上的文本 public String getText () { return text; } // 保存圖片到指定的輸出流 public static void output (BufferedImage image, OutputStream out) throws IOException { ImageIO.write(image, "JPEG", out); } // 調(diào)用這個(gè)方法得到驗(yàn)證碼 public BufferedImage getImage () { BufferedImage image = createImage();//創(chuàng)建圖片緩沖區(qū) Graphics2D g2 = (Graphics2D)image.getGraphics();//得到繪制環(huán)境 StringBuilder sb = new StringBuilder();//用來(lái)裝載生成的驗(yàn)證碼文本 // 向圖片中畫(huà)4個(gè)字符 for(int i = 0; i < 4; i++) {//循環(huán)四次，每次生成一個(gè)字符 String s = randomChar() + "";//隨機(jī)生成一個(gè)字母 sb.append(s); //把字母添加到sb中 float x = i * 1.0F * w / 4; //設(shè)置當(dāng)前字符的x軸坐標(biāo) g2.setFont(randomFont()); //設(shè)置隨機(jī)字體 g2.setColor(randomColor()); //設(shè)置隨機(jī)顏色 g2.drawString(s, x, h-5); //畫(huà)圖 } this.text = sb.toString(); //把生成的字符串賦給了this.text drawLine(image); //添加干擾線 return image; } public static void main(String[] args) throws FileNotFoundException, IOException { VerifyCode vc = new VerifyCode();//創(chuàng)建VerifyCode類的對(duì)象 BufferedImage bi = vc.getImage();//調(diào)用getImge()方法獲得一個(gè)BufferedImage對(duì)象 VerifyCode.output(bi, new FileOutputStream("C:/驗(yàn)證碼3.jpg"));//調(diào)用靜態(tài)方法output()方法將圖片保存在文件輸出流中 System.out.println(vc.getText());//在控制臺(tái)上打印驗(yàn)證碼的文本值 }} |
VerifyCodeServlet：
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package com.lhy.web.servlet;import java.awt.image.BufferedImage;import java.io.IOException;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class VerifyCodeServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { /* * 1. 生成圖片 * 2. 保存圖片上的文本到session域中 * 3. 把圖片響應(yīng)給客戶端 */ VerifyCode vc = new VerifyCode(); BufferedImage image = vc.getImage(); request.getSession().setAttribute("session_vcode", vc.getText());//保存圖片上的文本到session域 VerifyCode.output(image, response.getOutputStream()); }} |
LoginServlet:
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package com.lhy.web.servlet;import java.io.IOException;import javax.servlet.RequestDispatcher;import javax.servlet.ServletException;import javax.servlet.http.Cookie;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import javax.servlet.http.HttpSession;public class LoginServlet extends HttpServlet { public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { /* * 校驗(yàn)驗(yàn)證碼 * 1. 從session中獲取正確的驗(yàn)證碼 * 2. 從表單中獲取用戶填寫(xiě)的驗(yàn)證碼 * 3. 進(jìn)行比較！ * 4. 如果相同，向下運(yùn)行，否則保存錯(cuò)誤信息到request域，轉(zhuǎn)發(fā)到login.jsp */ String sessionCode = (String) request.getSession().getAttribute("session_vcode"); String paramCode = request.getParameter("verifyCode"); if(!paramCode.equalsIgnoreCase(sessionCode)) { request.setAttribute("msg", "驗(yàn)證碼錯(cuò)誤！"); request.getRequestDispatcher("/login.jsp").forward(request, response); return; } /* * 1. 獲取表單數(shù)據(jù) */ // 處理中文問(wèn)題 request.setCharacterEncoding("utf-8"); // 獲取 String username = request.getParameter("username"); String password = request.getParameter("password"); /* * 2. 校驗(yàn)用戶名和密碼是否正確 */ if("itcast".equalsIgnoreCase(username)) {//登錄成功 /* * 附加項(xiàng)：把用戶名保存到cookie中，發(fā)送給客戶端瀏覽器 * 當(dāng)再次打開(kāi)login.jsp時(shí)，login.jsp中會(huì)讀取request中的cookie，把它顯示到用戶名文本框中 */ Cookie cookie = new Cookie("uname", username);//創(chuàng)建Cookie cookie.setMaxAge(60*60*24);//設(shè)置cookie命長(zhǎng)為1天 response.addCookie(cookie);//保存cookie /* * 3. 如果成功 * > 保存用戶信息到session中 * > 重定向到succ1.jsp */ HttpSession session = request.getSession();//獲取session session.setAttribute("username", username);//向session域中保存用戶名 response.sendRedirect("/Test/succ1.jsp"); } else {//登錄失敗 /* * 4. 如果失敗 * > 保存錯(cuò)誤信息到request域中 * > 轉(zhuǎn)發(fā)到login.jsp */ request.setAttribute("msg", "用戶名或密碼錯(cuò)誤!"); RequestDispatcher qr = request.getRequestDispatcher("/login.jsp");//得到轉(zhuǎn)發(fā)器 qr.forward(request, response);//轉(zhuǎn)發(fā) } } } |
login.jsp:
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<%@ 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%>" rel="external nofollow" > <title>My JSP 'login.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" rel="external nofollow" > --><script type="text/javascript">function _change() { /* 1. 得到img元素 2. 修改其src */ var imgEle = document.getElementById("img"); imgEle.src = "<%=basePath%>servlet/VerifyCodeServlet?a=" + new Date().getTime();}</script> </head> <body><%-- 本頁(yè)面提供登錄表單，還要顯示錯(cuò)誤信息 --%><h1>登錄</h1><%/*讀取名為uname的Cookie!如果為空顯示：""如果不為空顯示：Cookie的值*/String uname = "";Cookie[] cs = request.getCookies();//獲取請(qǐng)求中所有的cookieif(cs != null) {// 如果存在cookie for(Cookie c : cs) {//循環(huán)遍歷所有的cookie if("uname".equals(c.getName())) {//查找名為uname的cookie uname = c.getValue();//獲取這個(gè)cookie的值，給uname這個(gè)變量 } }}%><% String message = ""; String msg = (String)request.getAttribute("msg");//獲取request域中的名為msg的屬性 if(msg != null) { message = msg; }%><font color="red"><b><%=message %> </b></font><form action="servlet/LoginServlet" method="post"> <%-- 把cookie中的用戶名顯示到用戶名文本框中 --%> 用戶名：<input type="text" name="username" value="<%=uname%>"/><br/> 密 碼：<input type="password" name="password"/><br/> 驗(yàn)證碼：<input type="text" name="verifyCode" size="3"/> <img id="img" src="<%=basePath%>servlet/VerifyCodeServlet"/> <a href="javascript:_change()" rel="external nofollow" >換一張</a> <br/> <input type="submit" value="登錄"/></form> </body></html> |
loginsuccess：
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<body><h1>succ1</h1><%String username = (String)session.getAttribute("username");if(username == null) { /* 1. 向request域中保存錯(cuò)誤信息，轉(zhuǎn)發(fā)到login.jsp */ request.setAttribute("msg", "您還沒(méi)有登錄!請(qǐng)先登錄!"); request.getRequestDispatcher("/login.jsp").forward(request, response); return;}%> |
歡迎歡迎，熱烈歡迎，歡迎<%=username %>領(lǐng)導(dǎo)指導(dǎo)工作！
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</body></html> |
配置文件：
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<servlet> <servlet-name>LoginServlet</servlet-name> <servlet-class>com.lhy.web.servlet.LoginServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>LoginServlet</servlet-name> <url-pattern>/servlet/LoginServlet</url-pattern> </servlet-mapping> <servlet> <servlet-name>VerifyCodeServlet</servlet-name> <servlet-class>com.lhy.web.servlet.VerifyCodeServlet</servlet-class> </servlet> <servlet-mapping> <servlet-name>VerifyCodeServlet</servlet-name> <url-pattern>/servlet/VerifyCodeServlet</url-pattern> </servlet-mapping> |
建議：生成驗(yàn)證碼的Servlet最好設(shè)置成不緩存，這樣就不用再頁(yè)面請(qǐng)求驗(yàn)證碼圖片的時(shí)候加上時(shí)間戳了，加上時(shí)間戳就是欺騙瀏覽器防止瀏覽器讀取緩存里的驗(yàn)證碼圖片，而點(diǎn)擊換一張后沒(méi)反應(yīng)。 這樣的不是很好的一點(diǎn)就是，每次點(diǎn)擊換一張，瀏覽器都會(huì)把新獲取的圖片緩存到本地，而在Servlet里設(shè)置不緩存，就不會(huì)緩存到本地了。
總結(jié)
以上所述是小編給大家介紹的JAVA驗(yàn)證碼工具實(shí)例代碼，希望對(duì)大家有所幫助，如果大家有任何疑問(wèn)請(qǐng)給我留言，小編會(huì)及時(shí)回復(fù)大家的。在此也非常感謝大家對(duì)服務(wù)器之家網(wǎng)站的支持！
原文鏈接：http://www.cnblogs.com/lihaoyang/p/7131512.html
