实验七 会话编程实验学生.docx

1、实验七 会话编程实验学生实验七 会话编程实验实验目的： 掌握会话的基本知识熟悉会话的生命周期 掌握Cookie和Session实现会话跟踪实验内容：1、 假设学生登录一个图书管理系统，在登录界面上提供学生输入账号、密码、验证码（可以使用Servlet生成4位随机数的验证码，并保存在会话对象中，同时生成带干扰的验证码图片，登录页面使用此Servlet生成的验证码），并给学生选择是否保存Cookie，如果保存，选择保存时间。登录成功后，跳转到的页面上显示学生的账号信息，学生也可以自己退出系统。实验操作步骤1 新建一个Web Project，工程名为ExperiSevenCookieSession，

2、新建一个登录页面文件login.jsp，设置提示学生用户登录的账号、密码、验证码框，复选框提示用户是否决定选择Cookie的保存时间。界面如图1所示。login.jsp的代码如下： 登录页面 用户名： 密  码： 验证码： 一天 一周 一月 时间内不再重新登录 图1 登录界面2 在src目录下新建一个Servlet，类名CheckCodeGet，用于生成验证码，验证码是随机生成的数字，CheckCodeGet.java代码如下：package cn.javaee.session;import java.awt.Color;import java.awt.Font;import jav

3、a.awt.Graphics;import java.awt.image.BufferedImage;import java.io.IOException;import java.util.Random;import javax.servlet.ServletConfig;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletRespo

4、nse;import com.sun.image.codec.jpeg.JPEGCodec;import com.sun.image.codec.jpeg.JPEGImageEncoder;/本Servlet的功能用于生成验证码public class CheckCodeGet extends HttpServlet private static final long serialVersionUID=1L; private final int TYPE_NUMBER=0; private final int TYPE_LETTER=1; private final int TYPE_MULT

5、IPLE=2; private int width; private int height; private int count; private int type; private String validate_code; private Random random; private Font font; private int line; /* * Constructor of the object. */ public CheckCodeGet() super(); /* * Destruction of the servlet. */ public void destroy() su

6、per.destroy(); / Just puts destroy string in log / Put your code here /* * The doGet method of the servlet. * * This method is called when a form has its tag value method equals to get. * * param request the request send by the client to the server * param response the response send by the server to

7、 the client * throws ServletException if an error occurred * throws IOException if an error occurred */ public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException response.setHeader(Pragma, No-cache); response.setHeader(Cache-Control,no-cache); r

8、esponse.setDateHeader(Expires,0);/ 不过期 response.setContentType(image/jpeg); /响应类型为图片 String reqCount=request.getParameter(count); String reqWidth=request.getParameter(width); String reqHeight=request.getParameter(height); String reqType=request.getParameter(type); if(reqCount!=null & reqCount!=) thi

9、s.count=Integer.parseInt(reqCount); if(reqWidth!=null & reqWidth!=) this.width=Integer.parseInt(reqWidth); if(reqHeight!=null & reqHeight!=) this.height=Integer.parseInt(reqHeight); if(reqType!=null & reqType!=) this.type=Integer.parseInt(reqType); font =new Font(Courier New,Font.BOLD,width/count);

10、BufferedImage image=new BufferedImage(width,height,BufferedImage.TYPE_INT_RGB); Graphics g=image.getGraphics(); g.setColor(getRandColor(160,240); g.fillRect(0, 0, width, height); g.setColor(getRandColor(20,100); g.setFont(font); validate_code=getValidateCode(count,type); request.getSession().setAttr

11、ibute(validate_code,validate_code); /将验证码存放到Session中，用于和输入的进行比较 for (int i=0;i255) from=255; if (to255) to=255; int rang=Math.abs(to-from); int r=from+random.nextInt(rang); / 红色 int g=from+random.nextInt(rang); / 蓝色 int b=from+random.nextInt(rang); / 绿色 return new Color(r,g,b); /获得验证码字符串 private Str

12、ing getValidateCode(int size,int type) StringBuffer validate_code=new StringBuffer(); for (int i=0;isize;i+) validate_code.append(getOneChar(type); return validate_code.toString(); / 根据验证码类型取得实际验证字符 / 类型0-取得0-9之间的数字 / 类型1-取得A-Z之间的字母 / 类型2-随机取得数字或是字母的组合 private String getOneChar(int type) String resu

13、lt=null; switch(type) case TYPE_NUMBER: result=String.valueOf(random.nextInt(10); break; case TYPE_LETTER: result=String.valueOf(char)(random.nextInt(26)+65); break; case TYPE_MULTIPLE: if (random.nextBoolean() result=String.valueOf(random.nextInt(10); else result=String.valueOf(char)(random.nextInt

14、(26)+65); break; default: result=null; break; if(result=null) throw new NullPointerException(获取验证码出错); return result; /* * The doPost method of the servlet. * * This method is called when a form has its tag value method equals to post. * * param request the request send by the client to the server *

15、 param response the response send by the server to the client * throws ServletException if an error occurred * throws IOException if an error occurred */ public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException doGet(request,response); /* * In

16、itialization of the servlet. * * throws ServletException if an error occurs */ public void init(ServletConfig config) throws ServletException super.init(config); width=150; height=50; count=4; type=TYPE_NUMBER; random=new Random(); line=200; 3 配置web.xml，添加对CheckCodeGet的配置，配置代码如下： This is the descrip

17、tion of my J2EE component This is the display name of my J2EE component CheckCodeGet cn.javaee.session.CheckCodeGet CheckCodeGet /CheckCodeGet 4 可以发布工程进行测试登录页面，能够打开如图1所示的界面。输入如图2所示的正确结，点击“提交”按钮后，读取数据库中的记录，查找和用户账号及密码匹配的记录，如果找到，转到主页mainPage.jsp，提示用户登录成功，如图3所示。如果找不到，再次转到登录界面。在src下新建一个Servelt类LoginServl

18、et用于处理“提交”表单后的处理，LoginServlet.java的代码如下：package cn.javaee.session;import java.io.IOException;import java.io.PrintWriter;import .URLEncoder;import java.sql.Connection;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import javax.servlet.Se

19、rvletConfig;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 javax.servlet.http.HttpSession;public class LoginServlet extends HttpServlet priv

20、ate Connection cn = null; public LoginServlet() super(); / 销毁方法，关闭数据库连接，释放对象占用内存 public void destroy() / TODO Auto-generated method stub super.destroy(); try if (cn != null & (!cn.isClosed() cn.close(); cn = null; catch (Exception e) System.out.println(Destroy Error: + e.getMessage(); public void do

21、Get(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException doPost(request, response); public void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException String userID = request.getParameter(userName); String passw

22、ord = request.getParameter(password); String sql = select * from student_info where stu_id = + userID + ; Statement st = null; try st = cn.createStatement(); catch (SQLException e1) / TODO Auto-generated catch block e1.printStackTrace(); ResultSet rs = null; try rs = st.executeQuery(sql); catch (SQL

23、Exception e) / TODO Auto-generated catch block e.printStackTrace(); try if (rs.next() String dbPassword = rs.getString(stu_pwd).toString(); String dbUserName=rs.getString(stu_name).toString(); if (dbPassword.equals(password) / 输入的密码正确 String cookSelected = request.getParameter(chkSelect); if (cookSe

24、lected != null) / 设置Cookie的保存时间 Cookie name = new Cookie(myname,URLEncoder.encode(userID,utf-8); Cookie pass = new Cookie(mypass,URLEncoder.encode(password,utf-8); String ageString=new String(request.getParameter(selectTime).getBytes(ISO-8859-1),UTF-8); /System.out.println(ageString); if (ageString.

25、equals(一天) name.setMaxAge(24*60*60); pass.setMaxAge(24*60*60); else if (ageString.equals(一周) name.setMaxAge(7*24*60*60); pass.setMaxAge(7*24*60*60); else if(ageString.equals(一月) /假定一月就按30天算，不计详细的哪个月份 name.setMaxAge(30*24*60*60); pass.setMaxAge(30*24*60*60); response.addCookie(name); response.addCookie(pass); HttpSession session=request.getSession(true); session.setAttribute(userName,dbUserName);