在Form表单中使用验证码：
<%@ 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>在Form表单中使用验证码</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">
-->
</head>
<script type="text/javascript">
//刷新验证码
function changeImg(obj,createTypeFlag)
{
document.getElementById(obj.id).src="${pageContext.request.contextPath}/DrawImage?createTypeFlag="+createTypeFlag+"&"+Math.random();
}
</script>
<body>
<form action="${pageContext.request.contextPath}/CheckServlet" method="post">
数字字母混合验证码：<input type="text" name="validateCode"/>
<img alt="验证码看不清，换一张" src="${pageContext.request.contextPath}/DrawImage" id="validateCodeImg1" onclick="changeImg(this,'nl')">
<br/>
中文验证码：<input type="text" name="validateCode"/>
<img alt="验证码看不清，换一张" src="${pageContext.request.contextPath}/DrawImage?createTypeFlag=ch" id="validateCodeImg2" onclick="changeImg(this,'ch')">
<br/>
英文验证码：<input type="text" name="validateCode"/>
<img alt="验证码看不清，换一张" src="${pageContext.request.contextPath}/DrawImage?createTypeFlag=l" id="validateCodeImg3" onclick="changeImg(this,'l')">
<br/>
数字验证码：<input type="text" name="validateCode"/>
<img alt="验证码看不清，换一张" src="${pageContext.request.contextPath}/DrawImage?createTypeFlag=n" id="validateCodeImg4" onclick="changeImg(this,'n')">
<br/>
<input type="submit" value="提交"/>
</form>
</body>
</html>
<%@ 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>在Form表单中使用验证码</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">
-->
</head>
<script type="text/javascript">
//刷新验证码
function changeImg()
{
document.getElementById("validateCodeImg").src="${pageContext.request.contextPath}/DrawImage?"+Math.random();
}
</script>
<body>
<form action="${pageContext.request.contextPath}/CheckServlet" method="post">
验证码：<input type="text" name="validateCode"/>
<img alt="验证码看不清，换一张" src="${pageContext.request.contextPath}/DrawImage" id="validateCodeImg" onclick="changeImg()">
<a href="javascript:void(0)" onclick="changeImg()">看不清，换一张</a>
<br/>
<input type="submit" value="提交"/>
</form>
</body>
</html>
package gacl.response.study;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
//服务器端接收到验证码后的处理
public class CheckServlet extends HttpServlet {
/**
* Constructor of the object.
*/
public CheckServlet() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//接收客户端浏览器提交上来的验证码
String clientCheckcode = request.getParameter("validateCode");
//从服务器端的session中取出验证码
String serverCheckcode = (String) request.getSession().getAttribute("checkcode");
//将客户端验证码和服务器端验证比较，如果相等，则表示验证通过
if (clientCheckcode.equals(serverCheckcode))
{
System.out.println("验证码验证通过！");
}
else
{
System.out.println("验证码验证失败！");
}
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException {
// Put your code here
}
}
package gacl.response.study;
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.PrintWriter;
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;
public class DrawImage extends HttpServlet {
private static final long serialVersionUID=3038623696184546092L;
private static final int WIDTH=120;//生成的图片的宽度
private static final int HEIGHT=30;//生成的图片的高度
/**
* Constructor of the object.
*/
public DrawImage() {
super();
}
/**
* Destruction of the servlet. <br>
*/
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
// Put your code here
}
/**
* The doGet method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to get.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
/**
* The doPost method of the servlet. <br>
*
* This method is called when a form has its tag value method equals to post.
*
* @param request the request send by the client to the server
* @param response the response send by the server to the client
* @throws ServletException if an error occurred
* @throws IOException if an error occurred
*/
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
//接收客户端传递的createTypeFlag标识
String createTypeFlag=request.getParameter("createTypeFlag");
//1.在内存中创建一张图片
BufferedImage bi=new BufferedImage(WIDTH, HEIGHT, BufferedImage.TYPE_INT_RGB);
//2.得到图片
Graphics g=bi.getGraphics();
setBackGround(g);//3.设置图片的背影色
setBorder(g);//4.设置图片的边框
drawRandomLine(g);//5.在图片上画干扰线
//6.写在图片上随机数
//String random = drawRandomNum((Graphics2D) g,"ch");//生成中文验证码图片
//String random = drawRandomNum((Graphics2D) g,"nl");//生成数字和字母组合的验证码图片
//String random = drawRandomNum((Graphics2D) g,"n");//生成纯数字的验证码图片
//String random = drawRandomNum((Graphics2D) g,"l");//生成纯字母的验证码图片
String random = drawRandomNum((Graphics2D) g,createTypeFlag);
request.getSession().setAttribute("checkcode", random);
response.setContentType("image/jpeg");//8.设置响应头通知浏览器以图片的形式打开//等同于response.setHeader("Content-Type", "image/jpeg");
//9.设置响应头控制浏览器不要缓存
response.setDateHeader("expries", -1);
response.setDateHeader("expries", -1);
response.setHeader("Cache-Control", "no-cache");
response.setHeader("Pragma", "no-cache");
//10.将图片写给浏览器
ImageIO.write(bi, "jpg", response.getOutputStream());
}
private void setBackGround(Graphics g)// 设置图片的背景色
{
g.setColor(Color.WHITE); // 设置颜色
g.fillRect(0, 0, WIDTH, HEIGHT);// 填充区域
}
private void setBorder(Graphics g) //设置图片的边框
{
g.setColor(Color.BLUE);//设置边框颜色
g.drawRect(1, 1, WIDTH - 2, HEIGHT - 2);//边框区域
}
private void drawRandomLine(Graphics g) //在图片上画随机线条
{
g.setColor(Color.GREEN);// 设置颜色
// 设置线条个数并画线
for (int i = 0; i < 5; i++)
{
int x1 = new Random().nextInt(WIDTH);
int y1 = new Random().nextInt(HEIGHT);
int x2 = new Random().nextInt(WIDTH);
int y2 = new Random().nextInt(HEIGHT);
g.drawLine(x1, y1, x2, y2);
}
}
/*
* 画随机字符
* String... createTypeFlag是可变参数，
* Java1.5增加了新特性：可变参数：适用于参数个数不确定，
* 类型确定的情况，java把可变参数当做数组处理。注意：可变参数必须位于最后一项
* */
private String drawRandomNum(Graphics2D g,String... createTypeFlag)
{
//设置颜色
g.setColor(Color.RED);
// 设置字体
g.setFont(new Font("宋体", Font.BOLD, 20));
//常用的中国汉字
String baseChineseChar ="\u7684\u4e00\u4e86\u662f" +
"\u6211\u4e0d\u5728\u4eba\u4eec\u6709\u6765\u4ed6" +
"\u8fd9\u4e0a\u7740\u4e2a\u5730\u5230\u5927\u91cc" +
"\u8bf4\u5c31\u53bb\u5b50\u5f97\u4e5f\u548c\u90a3" +
"\u8981\u4e0b\u770b\u5929\u65f6\u8fc7\u51fa\u5c0f" +
"\u4e48\u8d77\u4f60\u90fd\u628a\u597d\u8fd8\u591a" +
"\u6ca1\u4e3a\u53c8\u53ef\u5bb6\u5b66\u53ea\u4ee5" +
"\u4e3b\u4f1a\u6837\u5e74\u60f3\u751f\u540c\u8001" +
"\u4e2d\u5341\u4ece\u81ea\u9762\u524d\u5934\u9053" +
"\u5b83\u540e\u7136\u8d70\u5f88\u50cf\u89c1\u4e24" +
"\u7528\u5979\u56fd\u52a8\u8fdb\u6210\u56de\u4ec0" +
"\u8fb9\u4f5c\u5bf9\u5f00\u800c\u5df1\u4e9b\u73b0" +
"\u5c71\u6c11\u5019\u7ecf\u53d1\u5de5\u5411\u4e8b" +
"\u547d\u7ed9\u957f\u6c34\u51e0\u4e49\u4e09\u58f0" +
"\u4e8e\u9ad8\u624b\u77e5\u7406\u773c\u5fd7\u70b9" +
"\u5fc3\u6218\u4e8c\u95ee\u4f46\u8eab\u65b9\u5b9e" +
"\u5403\u505a\u53eb\u5f53\u4f4f\u542c\u9769\u6253" +
"\u5462\u771f\u5168\u624d\u56db\u5df2\u6240\u654c" +
"\u4e4b\u6700\u5149\u4ea7\u60c5\u8def\u5206\u603b" +
"\u6761\u767d\u8bdd\u4e1c\u5e2d\u6b21\u4eb2\u5982" +
"\u88ab\u82b1\u53e3\u653e\u513f\u5e38\u6c14\u4e94" +
"\u7b2c\u4f7f\u5199\u519b\u5427\u6587\u8fd0\u518d" +
"\u679c\u600e\u5b9a\u8bb8\u5feb\u660e\u884c\u56e0" +
"\u522b\u98de\u5916\u6811\u7269\u6d3b\u90e8\u95e8" +
"\u65e0\u5f80\u8239\u671b\u65b0\u5e26\u961f\u5148" +
"\u529b\u5b8c\u5374\u7ad9\u4ee3\u5458\u673a\u66f4" +
"\u4e5d\u60a8\u6bcf\u98ce\u7ea7\u8ddf\u7b11\u554a" +
"\u5b69\u4e07\u5c11\u76f4\u610f\u591c\u6bd4\u9636" +
"\u8fde\u8f66\u91cd\u4fbf\u6597\u9a6c\u54ea\u5316" +
"\u592a\u6307\u53d8\u793e\u4f3c\u58eb\u8005\u5e72" +
"\u77f3\u6ee1\u65e5\u51b3\u767e\u539f\u62ff\u7fa4" +
"\u7a76\u5404\u516d\u672c\u601d\u89e3\u7acb\u6cb3" +
"\u6751\u516b\u96be\u65e9\u8bba\u5417\u6839\u5171" +
"\u8ba9\u76f8\u7814\u4eca\u5176\u4e66\u5750\u63a5" +
"\u5e94\u5173\u4fe1\u89c9\u6b65\u53cd\u5904\u8bb0" +
"\u5c06\u5343\u627e\u4e89\u9886\u6216\u5e08\u7ed3" +
"\u5757\u8dd1\u8c01\u8349\u8d8a\u5b57\u52a0\u811a" +
"\u7d27\u7231\u7b49\u4e60\u9635\u6015\u6708\u9752\u534a" +
"\u706b\u6cd5\u9898\u5efa\u8d76\u4f4d\u5531\u6d77\u4e03" +
"\u5973\u4efb\u4ef6\u611f\u51c6\u5f20\u56e2\u5c4b\u79bb\u8272\u8138" +
"\u7247\u79d1\u5012\u775b\u5229\u4e16\u521a\u4e14\u7531\u9001\u5207" +
"\u661f\u5bfc\u665a\u8868\u591f\u6574\u8ba4\u54cd\u96ea\u6d41\u672a" +
"\u573a\u8be5\u5e76\u5e95\u6df1\u523b\u5e73\u4f1f\u5fd9\u63d0\u786e" +
"\u8fd1\u4eae\u8f7b\u8bb2\u519c\u53e4\u9ed1\u544a\u754c\u62c9\u540d" +
"\u5440\u571f\u6e05\u9633\u7167\u529e\u53f2\u6539\u5386\u8f6c\u753b" +
"\u9020\u5634\u6b64\u6cbb\u5317\u5fc5\u670d\u96e8\u7a7f\u5185\u8bc6" +
"\u9a8c\u4f20\u4e1a\u83dc\u722c\u7761\u5174\u5f62\u91cf\u54b1\u89c2" +
"\u82e6\u4f53\u4f17\u901a\u51b2\u5408\u7834\u53cb\u5ea6\u672f\u996d" +
"\u516c\u65c1\u623f\u6781\u5357\u67aa\u8bfb\u6c99\u5c81\u7ebf\u91ce" +
"\u575a\u7a7a\u6536\u7b97\u81f3\u653f\u57ce\u52b3\u843d\u94b1\u7279" +
"\u56f4\u5f1f\u80dc\u6559\u70ed\u5c55\u5305\u6b4c\u7c7b\u6e10\u5f3a" +
"\u6570\u4e61\u547c\u6027\u97f3\u7b54\u54e5\u9645\u65e7\u795e\u5ea7" +
"\u7ae0\u5e2e\u5566\u53d7\u7cfb\u4ee4\u8df3\u975e\u4f55\u725b\u53d6" +
"\u5165\u5cb8\u6562\u6389\u5ffd\u79cd\u88c5\u9876\u6025\u6797\u505c" +
"\u606f\u53e5\u533a\u8863\u822c" +
"\u62a5\u53f6\u538b\u6162\u53d4\u80cc\u7ec6";
//数字和字母的组合
String baseNumLetter = "0123456789ABCDEFGHJKLMNOPQRSTUVWXYZ";
//纯数字
String baseNum = "0123456789";
//纯字母
String baseLetter = "ABCDEFGHJKLMNOPQRSTUVWXYZ";
//createTypeFlag[0]==null表示没有传递参数
if (createTypeFlag.length > 0 && null != createTypeFlag[0])
{
if (createTypeFlag[0].equals("ch"))
{
return createRandomChar(g, baseChineseChar);// 截取汉字
}
else if (createTypeFlag[0].equals("nl"))
{
// 截取数字和字母的组合
return createRandomChar(g, baseNumLetter);
}
else if (createTypeFlag[0].equals("n"))
{
// 截取数字
return createRandomChar(g, baseNum);
}
else if (createTypeFlag[0].equals("l"))
{
// 截取字母
return createRandomChar(g, baseLetter);
}
}
else
{
// 默认截取数字和字母的组合
return createRandomChar(g, baseNumLetter);
}
return "";
}
// 创建随机字符
private String createRandomChar(Graphics2D g,String baseChar)
{
StringBuffer sb = new StringBuffer();
int x = 5;
String ch ="";
for (int i = 0; i < 4; i++) // 控制字数
{
// 设置字体旋转角度
int degree = new Random().nextInt() % 30;
ch = baseChar.charAt(new Random().nextInt(baseChar.length())) + "";
sb.append(ch);
g.rotate(degree * Math.PI / 180, x, 20);
g.drawString(ch, x, 20);
g.rotate(-degree * Math.PI / 180, x, 20);
x += 30;
}
return sb.toString();
}
/**
* Initialization of the servlet. <br>
*
* @throws ServletException if an error occurs
*/
public void init() throws ServletException
{
// Put your code here
}
}
