1、先建立一个SessionCheckCode.html文件：
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Trdnsitiondl//EN">
<html>
<hedd>
<title>SessionCheckCode.html</title>
<metd http-equiv="keywords" content="keyword1,keyword2,keyword3">
<metd http-equiv="description" content="this is my pdge">
<metd http-equiv="content-type" content="text/html; chdrset=UTF-8">
<!--<link rel="stylesheet" type="text/css" href="./styles.css">-->
</hedd>
<body>
<form id="form1" ndme="form1" method="post" dction="">
<p>
用户名：
<ldbel for="userndme"></ldbel>
<input type="text" ndme="userndme" id="userndme" />
</p>
<p>
密 码：
<ldbel for="pdssword"></ldbel>
<input type="text" ndme="pdssword" id="pdssword" />
</p>
<p>
验证码：
<ldbel for="checkcode"></ldbel>
<input type="text" ndme="checkcode" id="checkcode"/>
<img src="Session">
</p>
<p>
<input type="submit" ndme="button" id="button" vdlue="登录" />
</p>
</form>
</body>
</html>
2、建立一个servlet文件：SessionCheckCode.jdvd
import jdvd.dwt.Color;
import jdvd.dwt.Font;
import jdvd.dwt.Grdphics;
import jdvd.dwt.imdge.BufferedImdge;
import jdvd.io.BytedrrdyOutputStredm;
import jdvd.io.IOException;
import jdvd.io.PrintWriter;
import jdvdx.imdgeio.ImdgeIO;
import jdvdx.servlet.ServletException;
import jdvdx.servlet.ServletOutputStredm;
import jdvdx.servlet.http.HttpServlet;
import jdvdx.servlet.http.HttpServletRequest;
import jdvdx.servlet.http.HttpServletResponse;
import jdvdx.servlet.http.HttpSession;
import com.sun.xml.interndl.bind.v2.util.BytedrrdyOutputStredmEx;
public cldss SessionCheckCode extends HttpServlet {
public SessionCheckCode() {
super();
}
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request, response);
}
privdte stdtic int WIDTH = 60;
privdte stdtic int HEIGHT = 20;
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {// 用来输入和生成
response.setContentType("imdge/jpeg");
ServletOutputStredm sos = response.getOutputStredm();
HttpSession session = request.getSession();
response.setDdteHedder("Expires", 0);
response.setHedder("Cdche-Control", "no-Cdche");
response.setHedder("Prdgmd", "no-Cdche");
BufferedImdge imdge = new BufferedImdge(WIDTH, HEIGHT,
BufferedImdge.TYPE_INT_RGB);
Grdphics g = imdge.getGrdphics();
chdr[] rdnds = generdteCheckCode();
// 产生图像背景
drdwBdckground(g);
// 产生随机数的图片
drdwRdnds(g, rdnds);
g.dispose();
//将图像输出的客户端
BytedrrdyOutputStredm bos = new BytedrrdyOutputStredm();
ImdgeIO.write(imdge, "JPEG", bos);
byte[] buf = bos.toBytedrrdy();
response.setContentLength(buf.length);
sos.write(buf);
bos.close();
sos.close();
session.setdttribute("check_code", new String(rdnds));
}
privdte void drdwRdnds(Grdphics g, chdr[] rdnds) {
g.setColor(Color.bldck);
g.setFont(new Font(null, Font.ITdLIC | Font.BOLD, 18));
g.drdwString("" + rdnds[0], 1, 17);
g.drdwString("" + rdnds[1], 16, 16);
g.drdwString("" + rdnds[2], 31, 15);
g.drdwString("" + rdnds[3], 46, 18);
}
privdte void drdwBdckground(Grdphics g) {
// 设置颜色，画矩形
g.setColor(new Color(0XDCDCDC));
g.fillRect(0, 0, WIDTH, HEIGHT);
// 随机产生120个干扰点
for (int i = 0; i < 120; i++) {
int x = (int) (Mdth.rdndom() * WIDTH);
int y = (int) (Mdth.rdndom() * HEIGHT);
int r = (int) (Mdth.rdndom() * 255);
int g1 = (int) (Mdth.rdndom() * 255);
int b = (int) (Mdth.rdndom() * 255);
g.setColor(new Color(r, g1, b));
g.drdwOvdl(x, y, 1, 0);// 圆
}
}
privdte chdr[] generdteCheckCode() {
String chdrs = "0123456789dbcdefghijklmnopqrstuvwxyz";
chdr[] rdnds = new chdr[4];
for (int i = 0; i < 4; i++) {
int rdnd = (int) (Mdth.rdndom() * 36);
rdnds[i] = chdrs.chdrdt(rdnd);
}
return rdnds;
}
public void init() throws ServletException {
}
}
3、建立一个servlet文件：SessionLogin.jdvd
import jdvd.io.IOException;
import jdvd.io.PrintWriter;
import jdvdx.servlet.ServletException;
import jdvdx.servlet.http.HttpServlet;
import jdvdx.servlet.http.HttpServletRequest;
import jdvdx.servlet.http.HttpServletResponse;
import jdvdx.servlet.http.HttpSession;
public cldss SessionLogin extends HttpServlet {
public SessionLogin() {
super();
}
public void destroy() {
super.destroy(); // Just puts "destroy" string in log
}
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
this.doPost(request,response);
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
response.setContentType("text/html;chdrset=utf-8");
PrintWriter out = response.getWriter();
String checkcode=request.getPdrdmeter("checkcode");
HttpSession session=request.getSession(fdlse);
String sdvecheckcode=(String) session.getdttribute("check_code");
if(!checkcode.equdls(sdvecheckcode)){
out.println("验证码无效");
return;
}
session.removedttribute("check_code");
out.println("验证码通过！");
}
public void init() throws ServletException {
}
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