package com.suse;
import java.awt.Color;
import java.awt.Graphics;
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 ImageServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws IOException {
BufferedImage bi =
new BufferedImage(
68,
22, BufferedImage.TYPE_INT_RGB);
Graphics g = bi.getGraphics();
Color c =
new Color(
200,
150,
255);
g.setColor(c);
g.fillRect(
0,
0,
68,
22);
char[] ch =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray();
Random r =
new Random();
int len = ch.length, index;
StringBuffer sb =
new StringBuffer();
for (
int i =
0; i <
4; i++) {
index = r.nextInt(len);
g.setColor(
new Color(r.nextInt(
88), r.nextInt(
188), r.nextInt(
255)));
g.drawString(ch[index] +
"", (i *
15) +
3,
18);
sb.append(ch[index]);
}
request.getSession().setAttribute(
"picode", sb.toString());
ImageIO.write(bi,
"JPG", response.getOutputStream());
}
public void doPost(HttpServletRequest request, HttpServletResponse response) {
}
}
package com.suse;
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;
public class LoginServlet extends HttpServlet {
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String picode = (String) request.getSession().getAttribute(
"picode");
String checkcode = request.getParameter(
"checkcode");
checkcode = checkcode.toUpperCase();
response.setContentType(
"text/html;charset=utf-8");
PrintWriter out = response.getWriter();
if (checkcode.equals(picode)) {
out.print(
"验证码正确");
}
else {
out.print(
"验证码输入错误");
}
out.flush();
out.close();
}
}
<%@ page language="java" import="java.util.*" pageEncoding="gbk"%>
<%
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>My JSP 'index.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">
<script type="text/javascript">
function reloadCode(){
var time=new Date().getTime();
document.getElementById("imgcode").src="<%=request.getContextPath()%>/servlet/ImageServlet?="
+time
}
</script>
</head>
<body>
<form action="<%=request.getContextPath()%>/servlet/LoginServlet" method="post">
验证码：
<input type="text" name="checkcode" />
<img alt="验证码" id="imgcode" src="<%=request.getContextPath()%>/servlet/ImageServlet"/>
<a href="javascript:reloadCode();">看不清楚
</a><br>
<input type="submit" value="提交" name="submit"/>
</form>
</body>
</html>
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5" xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<display-name></display-name>
<servlet>
<servlet-name>ImageServlet
</servlet-name>
<servlet-class>com.suse.ImageServlet
</servlet-class>
</servlet>
<servlet>
<servlet-name>LoginServlet
</servlet-name>
<servlet-class>com.suse.LoginServlet
</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ImageServlet
</servlet-name>
<url-pattern>/servlet/ImageServlet
</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>LoginServlet
</servlet-name>
<url-pattern>/servlet/LoginServlet
</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp
</welcome-file>
</welcome-file-list>
</web-app>
