import java.io.*;
import javax.servlet.*;
import javax.servlet.http.*;
public class LoginServlet extends HttpServlet
{protected void doGet(HttpServletRequest req, HttpServletResponse resp)throws ServletException,IOException
{ resp.setContentType("text/html;charset=gbk");
PrintWriter out=resp.getWriter();
try{
String myUserName=this.getInitParameter("name");
String myPassWord=this.getInitParameter("password");
HttpSession session=req.getSession();
String scode=(String)session.getAttribute("code");
String userName=req.getParameter("name");
String passWord=req.getParameter("password");
String code=req.getParameter("code");
out.println("<html><body>");
out.println("<br/>");
if(!code.toUpperCase().equals(scode)){out.println("Wrong Validate!");}
else if (userName.equals(myUserName)&&passWord.equals(myPassWord))
{out.println("Login Sucessed! ");}
else{out.println("Login Failed!");}
}
finally{out.close();}
}
protected void doPost(HttpServletRequest req,HttpServletResponse resp)throws ServletException,IOException{
doGet(req,resp);}
}
import java.awt.Color;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.IOException;
import java.io.OutputStream;
import javax.imageio.ImageIO;
import javax.servlet.*;
import javax.servlet.http.*;
public class CheckCodeServlet extends HttpServlet {
public void doGet(HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException {
resp.setContentType("image/jpeg");
OutputStream out = resp.getOutputStream();
try {
resp.setHeader("programa", "no-cache");
resp.setHeader("Cache-Control", "no-cache");
resp.setDateHeader("Expires", 0);
BufferedImage image = new BufferedImage(50, 18,
BufferedImage.TYPE_INT_RGB);
Graphics g = image.getGraphics();
g.setColor(Color.LIGHT_GRAY);
g.fillRect(0, 0, 50, 18);
g.setColor(Color.LIGHT_GRAY);
g.drawRect(0, 0, 50, 18);
String str = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
String code = "";
for (int i = 0; i < 4; i++) {
int k = (int) (Math.random() * 36);
char c = str.charAt(k);
code += c;
}
HttpSession session = req.getSession();
session.setAttribute("code", code);
g.setColor(Color.BLACK);
Font font = new Font("DIALOG", Font.ITALIC, 15);
g.setFont(font);
g.drawString(code, 3, 15);
ImageIO.write(image, "JPEG", out);
out.flush();
out.close();
} finally {
out.close();
}
}
protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
doGet(req,resp);}
}
<%@ page language="java" import="java.util.*" pageEncoding="ISO-8859-1"%>
<%
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>
<title>Login</title>
</head>
<BODY bgColor=#ffffff leftMargin=0 text=#000000 topMargin=30><center>
<form action="LoginServlet" method="get">
User <input maxlength=10 name="name" size=8><br>
Password <input type=password name="password" size=8><br>
Validate <input name=code size=8><br>
<img src="checkCodeServlet" onclick="self.location.reload();"/><br>
<input name=Submit type=submit value=Commit>
<input name=Submit2 type=reset value=Reset>
</form>
</body>
</html>
<web-app>
<servlet>
<servlet-name>CheckCodeServlet</servlet-name>
<servlet-class>Com.CheckCodeServlet</servlet-class>
</servlet>
<servlet>
<servlet-name>LoingServlet</servlet-name>
<servlet-class>Com.LoingServlet</servlet-class>
<init-param>
<param-name>name</param-name>
<param-value>abc</param-value>
</init-param>
<init-param>
<param-name>password</param-name>
<param-value>123</param-value>
</init-param>
</servlet>
<servlet-mapping>
<servlet-name>CheckCodeServlet</servlet-name>
<url-pattern>/CheckCodeServlet</url-pattern>
</servlet-mapping>
<servlet-mapping>
<servlet-name>LoingServlet</servlet-name>
<url-pattern>/LoingServlet</url-pattern>
</servlet-mapping>
</web-app>
