<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>$Title$</title>
</head>
<script type="text/javascript">
function reloadCode()
{
var time=new Date().getTime();
document.getElementById("imagecode").src="<%= request.getContextPath()%>/servlet/ImageServlet?d="+time;
}
</script>
<body>
<form action="<%= request.getContextPath()%>/servlet/UserServlet" method="post" >
用户名:<input type="text" name="uname"/>
<br>
密码:<input type="password" name="password"/>
<br>
验证码:<input type="text" name="checkCode"/>
<a href="javascript:reloadCode();">
<img alt="验证码" id="imagecode" src="<%= request.getContextPath()%>/servlet/ImageServlet"/>
看不清楚</a><br>
<input type="submit" value="登录">
</form>
</body>
</html>
package servlet;
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.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
@WebServlet(urlPatterns="/servlet/ImageServlet")
public class ImageServlet extends HttpServlet{
public void doGet(HttpServletRequest request,HttpServletResponse response) throws IOException{
//这个方法实现验证码的生成
BufferedImage bi=new BufferedImage(68, 22,BufferedImage.TYPE_INT_RGB);//创建图像缓冲区
Graphics g=bi.getGraphics(); //通过缓冲区创建一个画布
Color c=new Color(253, 161,255); //创建颜色
/*根据背景画了一个矩形框
*/
g.setColor(c);//为画布创建背景颜色
g.fillRect(0, 0, 68,22); //fillRect:填充指定的矩形
char[] ch="ABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789".toCharArray();//转化为字符型的数组
Random r=new Random();
int len=ch.length;
int index; //index用于存放随机数字
StringBuffer sb=new StringBuffer();
for(int i=0;i<4;i++)
{
index=r.nextInt(len);//产生随机数字
g.setColor(new Color(r.nextInt(88),r.nextInt(188),r.nextInt(255))); //设置颜色
g.drawString(ch[index]+"",(i*15)+3, 18);//画数字以及数字的位置
sb.append(ch[index]);
}
request.getSession().setAttribute("piccode",sb.toString()); //将数字保留在session中，便于后续的使用
ImageIO.write(bi, "JPG", response.getOutputStream());
}}
package servlet;
import java.io.IOException;
import java.io.PrintWriter;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
@WebServlet(urlPatterns="/servlet/UserServlet")
public class UserServlet extends HttpServlet {
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String uname = request.getParameter("uname");
String password = request.getParameter("password");
//验证码
String piccode = (String) request.getSession().getAttribute("piccode");
String checkCode = request.getParameter("checkCode"); //取值
checkCode = checkCode.toUpperCase(); //把字符全部转换为大写的（此语句可以用于验证码不区分大小写）
response.setContentType("text/html;charset=gbk");//解决乱码问题
PrintWriter out = response.getWriter();
if (checkCode.equals(piccode) && "lty".equals(uname) && "123456".equals(password)) {
//转跳页面
String contextPath = request.getContextPath();
HttpSession session = request.getSession();
session.setAttribute("uname",uname);
response.sendRedirect(contextPath + "/ok.jsp");
} else {
request.getRequestDispatcher("/index.jsp").forward(request, response);
}
out.flush();//将流刷新
out.close();//将流关闭
}
}
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
<title>Title</title>
</head>
<body>
<h2 style="color: cadetblue">
<% String uname = (String) request.getSession().getAttribute("uname");%>
<%=uname%> 登录成功！！！</h2>
</body>
</html>
