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 ="u7684u4e00u4e86u662f" +
"u6211u4e0du5728u4ebau4eecu6709u6765u4ed6" +
"u8fd9u4e0au7740u4e2au5730u5230u5927u91cc" +
"u8bf4u5c31u53bbu5b50u5f97u4e5fu548cu90a3" +
"u8981u4e0bu770bu5929u65f6u8fc7u51fau5c0f" +
"u4e48u8d77u4f60u90fdu628au597du8fd8u591a" +
"u6ca1u4e3au53c8u53efu5bb6u5b66u53eau4ee5" +
"u4e3bu4f1au6837u5e74u60f3u751fu540cu8001" +
"u4e2du5341u4eceu81eau9762u524du5934u9053" +
"u5b83u540eu7136u8d70u5f88u50cfu89c1u4e24" +
"u7528u5979u56fdu52a8u8fdbu6210u56deu4ec0" +
"u8fb9u4f5cu5bf9u5f00u800cu5df1u4e9bu73b0" +
"u5c71u6c11u5019u7ecfu53d1u5de5u5411u4e8b" +
"u547du7ed9u957fu6c34u51e0u4e49u4e09u58f0" +
"u4e8eu9ad8u624bu77e5u7406u773cu5fd7u70b9" +
"u5fc3u6218u4e8cu95eeu4f46u8eabu65b9u5b9e" +
"u5403u505au53ebu5f53u4f4fu542cu9769u6253" +
"u5462u771fu5168u624du56dbu5df2u6240u654c" +
"u4e4bu6700u5149u4ea7u60c5u8defu5206u603b" +
"u6761u767du8bddu4e1cu5e2du6b21u4eb2u5982" +
"u88abu82b1u53e3u653eu513fu5e38u6c14u4e94" +
"u7b2cu4f7fu5199u519bu5427u6587u8fd0u518d" +
"u679cu600eu5b9au8bb8u5febu660eu884cu56e0" +
"u522bu98deu5916u6811u7269u6d3bu90e8u95e8" +
"u65e0u5f80u8239u671bu65b0u5e26u961fu5148" +
"u529bu5b8cu5374u7ad9u4ee3u5458u673au66f4" +
"u4e5du60a8u6bcfu98ceu7ea7u8ddfu7b11u554a" +
"u5b69u4e07u5c11u76f4u610fu591cu6bd4u9636" +
"u8fdeu8f66u91cdu4fbfu6597u9a6cu54eau5316" +
"u592au6307u53d8u793eu4f3cu58ebu8005u5e72" +
"u77f3u6ee1u65e5u51b3u767eu539fu62ffu7fa4" +
"u7a76u5404u516du672cu601du89e3u7acbu6cb3" +
"u6751u516bu96beu65e9u8bbau5417u6839u5171" +
"u8ba9u76f8u7814u4ecau5176u4e66u5750u63a5" +
"u5e94u5173u4fe1u89c9u6b65u53cdu5904u8bb0" +
"u5c06u5343u627eu4e89u9886u6216u5e08u7ed3" +
"u5757u8dd1u8c01u8349u8d8au5b57u52a0u811a" +
"u7d27u7231u7b49u4e60u9635u6015u6708u9752u534a" +
"u706bu6cd5u9898u5efau8d76u4f4du5531u6d77u4e03" +
"u5973u4efbu4ef6u611fu51c6u5f20u56e2u5c4bu79bbu8272u8138" +
"u7247u79d1u5012u775bu5229u4e16u521au4e14u7531u9001u5207" +
"u661fu5bfcu665au8868u591fu6574u8ba4u54cdu96eau6d41u672a" +
"u573au8be5u5e76u5e95u6df1u523bu5e73u4f1fu5fd9u63d0u786e" +
"u8fd1u4eaeu8f7bu8bb2u519cu53e4u9ed1u544au754cu62c9u540d" +
"u5440u571fu6e05u9633u7167u529eu53f2u6539u5386u8f6cu753b" +
"u9020u5634u6b64u6cbbu5317u5fc5u670du96e8u7a7fu5185u8bc6" +
"u9a8cu4f20u4e1au83dcu722cu7761u5174u5f62u91cfu54b1u89c2" +
"u82e6u4f53u4f17u901au51b2u5408u7834u53cbu5ea6u672fu996d" +
"u516cu65c1u623fu6781u5357u67aau8bfbu6c99u5c81u7ebfu91ce" +
"u575au7a7au6536u7b97u81f3u653fu57ceu52b3u843du94b1u7279" +
"u56f4u5f1fu80dcu6559u70edu5c55u5305u6b4cu7c7bu6e10u5f3a" +
"u6570u4e61u547cu6027u97f3u7b54u54e5u9645u65e7u795eu5ea7" +
"u7ae0u5e2eu5566u53d7u7cfbu4ee4u8df3u975eu4f55u725bu53d6" +
"u5165u5cb8u6562u6389u5ffdu79cdu88c5u9876u6025u6797u505c" +
"u606fu53e5u533au8863u822c" +
"u62a5u53f6u538bu6162u53d4u80ccu7ec6";
//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
}
}