验证码出不来 好心人帮看看
jsp
<%@ page language="java" contentType="text/html; charset=utf-8"
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" "http://www.w3.org/TR/html4/loose.dtd">
<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">
</head>
<body>
验证码:<input type="text" name="checkcode"/>
<img alt="验证码" src="<%=request.getContextPath() %>/servlet/ImageServlet>"/>
<a href="javascript:reloadCode();">看不清楚</a><br>
</body>
</html>
package checkCode;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.util.Random;
import javax.imageio.ImageIO;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
public class ImageServlet extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
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("piccode", sb.toString());
ImageIO.write(bi, "JPG", response.getOutputStream());
}
}
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://java.sun.com/xml/ns/javaee" xsi:schemaLocation="http://java.sun.com/xml/ns/javaee http://java.sun.com/xml/ns/javaee/web-app_3_0.xsd" id="WebApp_ID" version="3.0">
<display-name>checkCode</display-name>
<servlet>
<servlet-name>ImageServlet</servlet-name>
<servlet-class>com.muke.ImageServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>ImageServlet</servlet-name>
<url-pattern>/Servlet/ImageServlet</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.html</welcome-file>
<welcome-file>index.htm</welcome-file>
<welcome-file>index.jsp</welcome-file>
<welcome-file>default.html</welcome-file>
<welcome-file>default.htm</welcome-file>
<welcome-file>default.jsp</welcome-file>
</welcome-file-list>
</web-app>
