登陆用户怎样获取验证码和保存用户到cookie中

User表：

User.java

package user.domain;

import java.io.Serializable;
import java.util.Date;

public class User implements Serializable{

	/**
	 * 
	 */
	private static final long serialVersionUID = 1L;
    
	private Integer id;
	private String name;
	private String pass;
	private Date birth;
	public User(){
		super();
	}
	public User(Integer id, String name, String pass, Date birth) {
		super();
		this.id = id;
		this.name = name;
		this.pass = pass;
		this.birth = birth;
	}
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPass() {
		return pass;
	}
	public void setPass(String pass) {
		this.pass = pass;
	}
	public Date getBirth() {
		return birth;
	}
	public void setBirth(Date birth) {
		this.birth = birth;
	}
	@Override
	public String toString() {
		return "User [id=" + id + ", name=" + name + ", pass=" + pass
				+ ", birth=" + birth + "]";
	}
	
}

UserDao.java

package user.dao;

import java.util.List;

import user.domain.User;

public interface UserDao {
    /**
	 * 根据用户和密码查询用户信息
	 */
	User checkLogin(String name,String pass);
	
}

实现接口的类UserDaoImp.java

package user.imp;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;

import user.dao.UserDao;
import user.domain.User;
import util.DBConn;

public class UserDaoImp implements UserDao {
	private Connection conn;
	private PreparedStatement pstmt;
	private ResultSet rs;

	public User checkLogin(String name, String pass) {
		User entity=null;
		String sql="select id,name,pass from user where name=? and pass=?";
		conn=DBConn.getConn();
		try {
			pstmt=conn.prepareStatement(sql);
			int index=1;
			pstmt.setString(index++,name);
			pstmt.setString(index++,pass);
			rs=pstmt.executeQuery();
			while(rs.next()){
				entity=new User();
				entity.setId(rs.getInt("id"));
				entity.setName(rs.getString("name"));
				entity.setPass(rs.getString("pass"));
			}
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}finally{
			DBConn.release(rs, pstmt);
		}
		
		
		return entity;
	}

}

工具包DBConn.java

package util;

import java.io.IOException;
import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.Properties;

public class DBConn {
 private static Connection conn;
 private DBConn(){
	 
 }
 public static Connection getConn(){
	 if(conn==null){
		 //创建集合对象
		 Properties properties=new Properties();
		 try {
			 //装载
			properties.load(DBConn.class.getClassLoader().getResourceAsStream("db.properties"));
		    //加载驱动程序
			Class.forName(properties.getProperty("driverClassName"));
			//获取连接对象
			conn=DriverManager.getConnection(properties.getProperty("url"),properties.getProperty("user"),properties.getProperty("pass"));
		 } catch (Exception e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	 }
	 return conn;
 }
 public static void update(String sql,Object params[],PreparedStatement pstmt) throws Exception{
	 pstmt=getConn().prepareStatement(sql);
	 for (int i = 0; i < params.length; i++) {
		pstmt.setObject(i+1, params[i]);
	}
	 pstmt.executeUpdate();
	 release(null,pstmt);
 }
public  static void release(ResultSet rs, PreparedStatement pstmt) {
     if (rs!=null) {
		try {
			rs.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
	if (pstmt!=null) {
		try {
			pstmt.close();
		} catch (SQLException e) {
			// TODO Auto-generated catch block
			e.printStackTrace();
		}
	}
}
}

工具包实现验证码RandomImage.java

package www.hbsi.csdn.util;

import java.awt.Color;

import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.util.Random;

import javax.servlet.http.HttpSession;

/**
 * 验证码
 * @author yanmei
 *
 */
public class RandomImage {
private final static int W=80;
private final static int H=30;
public static BufferedImage createImage(HttpSession session){
	//创建图片
	BufferedImage image=new BufferedImage(W, H, BufferedImage.TYPE_INT_RGB);
	//得到图形绘制的对象
	Graphics g=image.getGraphics();
	//设置背景颜色
	setBackGroud(g);
	//设置边框
	setBorder(g);
	//绘制内容
	StringBuffer sb=drawContent(g);
	session.setAttribute("checkCode", sb);
	//绘制干扰线
	drawDisturbline(g);
	return image;
}
private static void drawDisturbline(Graphics g) {
	g.setColor(Color.blue);
	Random r=new Random();
	for (int i = 0; i < 4; i++) {
		int x1 = r.nextInt(W);
		int y1 = r.nextInt(H);
		int x2 = r.nextInt(W);
		int y2 = r.nextInt(H);
		g.drawLine(x1, y1, x2, y2);
	}
}
private static StringBuffer drawContent(Graphics g) {
	// TODO Auto-generated method stub
	
	//字节资源
	String re = "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";
	//获取字符的长度
	int length=re.length();
	//随机操作对象
	Random r=new Random();
	//存储字符的对象
	StringBuffer sb=new StringBuffer();
	for (int i = 0; i < 4; i++) {
		//随机产生数字
		int index=r.nextInt(length);
		//获取字符
		char c=re.charAt(index);
		sb.append(c);
	}
	g.setColor(Color.black);
	g.drawString(sb.toString(),20,20);
	return sb;
}
private static void setBorder(Graphics g) {
	g.setColor(Color.black);
	g.drawRect(0, 0, W-2, H-2);
	
}
private static void setBackGroud(Graphics g) {
	// 绘制矩形
	g.setColor(Color.yellow);
	g.fillRect(0, 0, W, H);
	
}
}

ImageServlet.java

package www.csdn.day36.servlet;

import java.awt.Color;
import java.awt.Graphics;
import java.io.IOException;
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;

import www.hbsi.csdn.util.RandomImage;

public class ImageServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		// 禁止浏览器缓存数据
		response.setHeader("expires", "0");
		response.setHeader("Cache-Control", "no-cache");
		response.setHeader("Pragma", "no-cache");

		// 1.通知浏览器以图片的方式打开数据
		response.setContentType("image/jpeg");

		// 把图片显示给浏览器
		ImageIO.write(RandomImage.createImage(request.getSession()), "jpeg",
				response.getOutputStream());

	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		this.doGet(request, response);
	}

}

db.properties

url=jdbc:mysql://localhost:3306/csdn?useUnicode=true&characterEncoding=UTF-8
user=root
pass=113

web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app version="3.0" 
	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_3_0.xsd">
  <display-name></display-name>
  <servlet>
    <servlet-name>DemoServlet</servlet-name>
    <servlet-class>www.csdn.day36.servlet.DemoServlet</servlet-class>
  </servlet>
  <servlet>
    <servlet-name>ImageServlet</servlet-name>
    <servlet-class>www.csdn.day36.servlet.ImageServlet</servlet-class>
  </servlet> 
  <servlet>
    <servlet-name>Servlet1</servlet-name>
    <servlet-class>www.csdn.day36.servlet.Servlet1</servlet-class>
  </servlet>
  <servlet>
    <servlet-name>LoginServlet</servlet-name>
    <servlet-class>www.csdn.day36.servlet.LoginServlet</servlet-class>
  </servlet>
  <servlet>
    <servlet-name>ChaServlet</servlet-name>
    <servlet-class>www.csdn.day36.servlet.ChaServlet</servlet-class>
  </servlet>





  <servlet-mapping>
    <servlet-name>DemoServlet</servlet-name>
    <url-pattern>/servlet/DemoServlet</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>ImageServlet</servlet-name>
    <url-pattern>/servlet/ImageServlet</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>Servlet1</servlet-name>
    <url-pattern>/servlet/Servlet1</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>LoginServlet</servlet-name>
    <url-pattern>/login.do</url-pattern>
  </servlet-mapping>
  <servlet-mapping>
    <servlet-name>ChaServlet</servlet-name>
    <url-pattern>/chalogin.do</url-pattern>
  </servlet-mapping>	
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
</web-app>

ChaServlet.java

package www.csdn.day36.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class ChaServlet extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		 Cookie cookies[]=request.getCookies();
         if(cookies!=null){
        	 for(Cookie cookie:cookies){
        		 if("loginData".equals(cookie.getName())){
        			 String value=cookie.getValue();
        			 String data[]=value.split(":");
        			 String name=data[0];
        			 String pass=data[1];
        			 request.setAttribute("name", name);
        			 request.setAttribute("pass", pass);
        		 }
        	 }
         }
		
		request.getRequestDispatcher("./login.jsp").forward(request, response);
	}

	

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		this.doGet(request, response);
	}

}

LoginServlet.java

package www.csdn.day36.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import user.dao.UserDao;
import user.domain.User;
import user.imp.UserDaoImp;


public class LoginServlet extends HttpServlet {
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		UserDao userDao = new UserDaoImp();
		String checkCode = request.getParameter("checkCode");
		StringBuffer createCheckCode = (StringBuffer) request.getSession()
				.getAttribute("checkCode");
		String ccode = createCheckCode.toString();
		// System.out.println(ccode+"============="+checkCode);
		response.setContentType("text/html");
		response.setCharacterEncoding("UTF-8");
		PrintWriter out = response.getWriter();

		// 判断验证码
		if (ccode.equals(checkCode)) {
			// 获取登陆的名称
			String name = request.getParameter("name");
			// 获取登陆的密码
			String pass = request.getParameter("pass");

			User entity = userDao.checkLogin(name, pass);
			if (entity != null) {
				// 运行cookie保存数据
				Cookie cookie = new Cookie("loginData", name + ":" + pass);
				//System.out.println(cookie);
				cookie.setMaxAge(7 * 24 * 60 * 60);
				response.addCookie(cookie);
				out.print("用户名存在");
			} else {
				out.print("用户名和密码错误");
			}

		} else {
			out.print("验证码错误");
		}
		out.close();
	}

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		this.doGet(request, response);
	}

}

login.js

var errorDom;
window.onload = function() {
    //alert("12123");
	errorDom = document.getElementById("error");
	var loginBtnDom = document.getElementById("loginBtn");
	loginBtnDom.onclick = loginCustomer;
};

var loginCustomer = function() {
	var name=document.getElementById("cname").value;
	var pass=document.getElementById("cpass").value;
	var checkCode = document.getElementById("checkCode").value;
	//alert(checkCode);
	var xmlHttp = getXMLHttp();
	var data="name="+encodeURIComponent(name)+"&pass="+encodeURIComponent(pass)+"&checkCode="+encodeURIComponent(checkCode)+"&oper=login";
	xmlHttp.open("GET", "./login.do?"+data);

	xmlHttp.send();

	xmlHttp.onreadystatechange = checkLogin;

};

var checkLogin = function() {
	if (this.readyState == 4 && this.status == 200) {
		errorDom.innerText= this.responseText;
	}
};

util.js

function getXMLHttp() {
	var xmlHttp;
	try {
		// firefox Opera
		xmlHttp = new XMLHttpRequest();
	} catch (e) {
		try {
			// IE
			xmlHttp = new ActiveXObject("MSXML2.XMLHTTP5.0");
		} catch (ex) {
			xmlHttp = new ActiveXObject("Microsoft.XMLHTTP");
		}
	}
	return xmlHttp;
}

index.jsp

<%@ page language="java" import="java.util.*" 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">
<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">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
  	<a href="./chalogin.do">查询</a>
  </body>
</html>

主页面login.jsp

<%@ page language="java" import="java.util.*" 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">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'login.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">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->

  </head>
  
  <body>
     <div align="center">
        <form action="./login.do" method="post">
				<table border="1px" cellpadding="0" cellspacing="0">
					<tr>
						<td>用户名：</td>
						<td colspan="2"><input type="text" id="cname" value="${name}"/></td>
					</tr>
					<tr>
						<td>密码：</td>
						<td colspan="2"><input type="password" id="cpass"  value="${pass}"/></td>
					</tr>
					<tr>
						<td>验证码：</td>
						<td colspan="2"><input type="text" id="checkCode" /></td>
						<td><img alt="验证码" src="./servlet/ImageServlet" /></td>
					</tr>
					<tr align="center">
						<td colspan="3"><input type="button" value="登录" id="loginBtn" />
							<span id="error" style="font-size:12px; color: blue;"></span></td>
					</tr>
				</table>
			</form>
     </div>
  </body>
</html>