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 = "u7684\u4e00\u4e86\u662f\u6211\u4e0d\u5728\u4eba\u4eec\u6709\u6765\u4ed6\u8fd9\u4e0a\u7740\u4e2a\u5730\u5230\u5927\u91cc\u8bf4\u5c31\u53bb\u5b50\u5f97\u4e5f\u548c\u90a3\u8981\u4e0b\u770b\u5929\u65f6\u8fc7\u51fa\u5c0f\u4e48\u8d77\u4f60\u90fd\u628a\u597d\u8fd8\u591a\u6ca1\u4e3a\u53c8\u53ef\u5bb6\u5b66\u53ea\u4ee5\u4e3b\u4f1a\u6837\u5e74\u60f3\u751f\u540c\u8001\u4e2d\u5341\u4ece\u81ea\u9762\u524d\u5934\u9053\u5b83\u540e\u7136\u8d70\u5f88\u50cf\u89c1\u4e24\u7528\u5979\u56fd\u52a8\u8fdb\u6210\u56de\u4ec0\u8fb9\u4f5c\u5bf9\u5f00\u800c\u5df1\u4e9b\u73b0\u5c71\u6c11\u5019\u7ecf\u53d1\u5de5\u5411\u4e8b\u547d\u7ed9\u957f\u6c34\u51e0\u4e49\u4e09\u58f0\u4e8e\u9ad8\u624b\u77e5\u7406\u773c\u5fd7\u70b9\u5fc3\u6218\u4e8c\u95ee\u4f46\u8eab\u65b9\u5b9e\u5403\u505a\u53eb\u5f53\u4f4f\u542c\u9769\u6253\u5462\u771f\u5168\u624d\u56db\u5df2\u6240\u654c\u4e4b\u6700\u5149\u4ea7\u60c5\u8def\u5206\u603b\u6761\u767d\u8bdd\u4e1c\u5e2d\u6b21\u4eb2\u5982\u88ab\u82b1\u53e3\u653e\u513f\u5e38\u6c14\u4e94\u7b2c\u4f7f\u5199\u519b\u5427\u6587\u8fd0\u518d\u679c\u600e\u5b9a\u8bb8\u5feb\u660e\u884c\u56e0\u522b\u98de\u5916\u6811\u7269\u6d3b\u90e8\u95e8\u65e0\u5f80\u8239\u671b\u65b0\u5e26\u961f\u5148\u529b\u5b8c\u5374\u7ad9\u4ee3\u5458\u673a\u66f4\u4e5d\u60a8\u6bcf\u98ce\u7ea7\u8ddf\u7b11\u554a\u5b69\u4e07\u5c11\u76f4\u610f\u591c\u6bd4\u9636\u8fde\u8f66\u91cd\u4fbf\u6597\u9a6c\u54ea\u5316\u592a\u6307\u53d8\u793e\u4f3c\u58eb\u8005\u5e72\u77f3\u6ee1\u65e5\u51b3\u767e\u539f\u62ff\u7fa4\u7a76\u5404\u516d\u672c\u601d\u89e3\u7acb\u6cb3\u6751\u516b\u96be\u65e9\u8bba\u5417\u6839\u5171\u8ba9\u76f8\u7814\u4eca\u5176\u4e66\u5750\u63a5\u5e94\u5173\u4fe1\u89c9\u6b65\u53cd\u5904\u8bb0\u5c06\u5343\u627e\u4e89\u9886\u6216\u5e08\u7ed3\u5757\u8dd1\u8c01\u8349\u8d8a\u5b57\u52a0\u811a\u7d27\u7231\u7b49\u4e60\u9635\u6015\u6708\u9752\u534a\u706b\u6cd5\u9898\u5efa\u8d76\u4f4d\u5531\u6d77\u4e03\u5973\u4efb\u4ef6\u611f\u51c6\u5f20\u56e2\u5c4b\u79bb\u8272\u8138\u7247\u79d1\u5012\u775b\u5229\u4e16\u521a\u4e14\u7531\u9001\u5207\u661f\u5bfc\u665a\u8868\u591f\u6574\u8ba4\u54cd\u96ea\u6d41\u672a\u573a\u8be5\u5e76\u5e95\u6df1\u523b\u5e73\u4f1f\u5fd9\u63d0\u786e\u8fd1\u4eae\u8f7b\u8bb2\u519c\u53e4\u9ed1\u544a\u754c\u62c9\u540d\u5440\u571f\u6e05\u9633\u7167\u529e\u53f2\u6539\u5386\u8f6c\u753b\u9020\u5634\u6b64\u6cbb\u5317\u5fc5\u670d\u96e8\u7a7f\u5185\u8bc6\u9a8c\u4f20\u4e1a\u83dc\u722c\u7761\u5174\u5f62\u91cf\u54b1\u89c2\u82e6\u4f53\u4f17\u901a\u51b2\u5408\u7834\u53cb\u5ea6\u672f\u996d\u516c\u65c1\u623f\u6781\u5357\u67aa\u8bfb\u6c99\u5c81\u7ebf\u91ce\u575a\u7a7a\u6536\u7b97\u81f3\u653f\u57ce\u52b3\u843d\u94b1\u7279\u56f4\u5f1f\u80dc\u6559\u70ed\u5c55\u5305\u6b4c\u7c7b\u6e10\u5f3a\u6570\u4e61\u547c\u6027\u97f3\u7b54\u54e5\u9645\u65e7\u795e\u5ea7\u7ae0\u5e2e\u5566\u53d7\u7cfb\u4ee4\u8df3\u975e\u4f55\u725b\u53d6\u5165\u5cb8\u6562\u6389\u5ffd\u79cd\u88c5\u9876\u6025\u6797\u505c\u606f\u53e5\u533a\u8863\u822c\u62a5\u53f6\u538b\u6162\u53d4\u80cc\u7ec6";
	//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>