一次会话多次请求——京东——手机——华为nove5
目的是多次请求间共享数据——手机——加入购物车——对刚刚加入购物车的手机进行支付
验证码也是多次请求
Cookie基本使用（客户端会话跟踪技术）
一次会话中，每次请求都携带Cookie数据进行访问
//cookie-Servlet-A.java
package com.itheima.web.cookie;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.net.URLEncoder;
@WebServlet("/aServlet")
public class AServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//发送Cookie
//1. 创建Cookie对象
// Cookie cookie = new Cookie("username","zs");
String value = "张三";
//URL编码
value = URLEncoder.encode(value, "UTF-8");
System.out.println("存储数据："+value);
Cookie cookie = new Cookie("username",value);
//设置存活时间 ，1周 7天
cookie.setMaxAge(60*60*24*7);
//2. 发送Cookie，response
response.addCookie(cookie);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}//cookie-Servlet-B.java
package com.itheima.web.cookie;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.Cookie;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.net.URLDecoder;
@WebServlet("/bServlet")
public class BServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//获取Cookie
//1. 获取Cookie数组
Cookie[] cookies = request.getCookies();
//2. 遍历数组
for (Cookie cookie : cookies) {
//3. 获取数据
String name = cookie.getName();
if("username".equals(name)){
String value = cookie.getValue();
//URL解码
value = URLDecoder.decode(value,"UTF-8");
System.out.println(name+":"+value);
break;
}
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
Cookie原理
Cookie的实现是基于HTTP协议的
响应头：set-cookie 服务器看到这个头就知道你要给我传Cookie了
请求头：cookie 服务器看到这个头就知道我该给客户端传Cookie了
Cookie使用细节（Cookie持久化）
//设置存活时间 ，1周 7天
cookie.setMaxAge(60*60*24*7);
String value = "张三";
//URL编码
value = URLEncoder.encode(value, "UTF-8");
System.out.println("存储数据："+value);
Cookie cookie = new Cookie("username",value);
-----------------------------------------------------------
//URL解码
value = URLDecoder.decode(value,"UTF-8");
System.out.println(name+":"+value);
Session基本使用(更安全)
//session-SessionDemo-1.java
package com.itheima.web.session;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
@WebServlet("/demo1")
public class SessionDemo1 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//存储到Session中
//1. 获取Session对象
HttpSession session = request.getSession();
System.out.println(session);
//2. 存储数据
session.setAttribute("username","zs");
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}//session-SessionDemo-2
package com.itheima.web.session;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;
@WebServlet("/demo2")
public class SessionDemo2 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//获取数据，从session中
//1. 获取Session对象
HttpSession session = request.getSession();
System.out.println(session);
// 销毁
session.invalidate();
//2. 获取数据
Object username = session.getAttribute("username");
System.out.println(username);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
Session原理
Session是基于Cookie实现的，Session的地址值是永远不变的
Session使用细节（Session不能长期存储数据）
用于关闭浏览器后再打开仍保持用户登录状态
用于退出用户登录
// 销毁
session.invalidate();小结
购物车信息：Cookie
用户登录信息：Session
账户密码的“记住我”功能：Cookie
验证码（防止暴力注册）：Session
案例
jsp（调用html与css等实现前端界面）——web（对用户输入的数据进行验证和对其他jsp的跳转）——service（将mapper实现的sql方法调用，获取sqlsession连接池，获取usermapper文件中的方法，调用方法，释放资源）——mapper（对数据库简单的增删改查定义一些实现方法）——util（工具类，生成动态验证码，定义静态代码块连接池）——pojo（实体类，用户信息实体类，品牌实体类）
在哪填充记录的cookie呢——在login.jsp中，使用PL表达式
<p>Username:<input id="username" name="username" value="${cookie.username.value}" type="text"></p>
<p>Password:<input id="password" name="password" value="${cookie.password.value}" type="password"></p>
package com.itheima.web;
import com.itheima.pojo.User;
import com.itheima.service.UserService;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
@WebServlet("/loginServlet")
public class LoginServlet extends HttpServlet {
private UserService service = new UserService();
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1. 获取用户名和密码
String username = request.getParameter("username");
String password = request.getParameter("password");
//获取复选框数据
String remember = request.getParameter("remember");
//2. 调用service查询
User user = service.login(username, password);
//3. 判断
if(user != null){
//登录成功，跳转到查询所有的BrandServlet
//判断用户是否勾选记住我
if("1".equals(remember)){// "1" 要写前面，用输入参数去比对，避免输入null导致比对异常
//勾选了，发送Cookie
/**
* 登录后的页面要显示 用户名+欢迎您
* <h1>${user.username},欢迎您</h1>
* 属于一次会话的多个请求之间的数据传递
* 所以要数据共享在Cookie或Session中
*/
//1. 创建Cookie对象
Cookie c_username = new Cookie("username",username);
Cookie c_password = new Cookie("password",password);
// 设置Cookie的存活时间
c_username.setMaxAge( 60 * 60 * 24 * 7);
c_password.setMaxAge( 60 * 60 * 24 * 7);
//2. 发送
response.addCookie(c_username);
response.addCookie(c_password);
}
//将登陆成功后的user对象，存储到session
HttpSession session = request.getSession();
session.setAttribute("user",user);
//改为动态路径
String contextPath = request.getContextPath();
response.sendRedirect(contextPath+"/selectAllServlet");
}else {
// 登录失败,
// 存储错误信息到request
request.setAttribute("login_msg","用户名或密码错误");
// 跳转到login.jsp
request.getRequestDispatcher("/login.jsp").forward(request,response);
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
//register.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>欢迎注册</title>
<link href="css/register.css" rel="stylesheet">
</head>
<body>
<div class="form-div">
<div class="reg-content">
<h1>欢迎注册</h1>
<span>已有帐号？</span> <a href="login.html">登录</a>
</div>
<form id="reg-form" action="/brand-demo/registerServlet" method="post">
<table>
<tr>
<td>用户名</td>
<td class="inputs">
<input name="username" type="text" id="username">
<br>
<span id="username_err" class="err_msg" >${register_msg}</span>
</td>
</tr>
<tr>
<td>密码</td>
<td class="inputs">
<input name="password" type="password" id="password">
<br>
<span id="password_err" class="err_msg" style="display: none">密码格式有误</span>
</td>
</tr>
<tr>
<td>验证码</td>
<td class="inputs">
<input name="checkCode" type="text" id="checkCode">
<img id="checkCodeImg" src="/brand-demo/checkCodeServlet">
<a href="#" id="changeImg" >看不清？</a>
</td>
</tr>
</table>
<div class="buttons">
<input value="注 册" type="submit" id="reg_btn">
</div>
<br class="clear">
</form>
</div>
<script>
document.getElementById("changeImg").onclick = function () {
document.getElementById("checkCodeImg").src = "/brand-demo/checkCodeServlet?"+new Date().getMilliseconds();
}
</script>
</body>
</html>//RegisterServlet.java
package com.itheima.web;
import com.itheima.pojo.User;
import com.itheima.service.UserService;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.*;
import java.io.IOException;
@WebServlet("/registerServlet")
public class RegisterServlet extends HttpServlet {
private UserService service = new UserService();
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1. 获取用户名和密码数据
String username = request.getParameter("username");
String password = request.getParameter("password");
User user = new User();
user.setUsername(username);
user.setPassword(password);
// 获取用户输入的验证码
String checkCode = request.getParameter("checkCode");
// 程序生成的验证码，从Session获取
HttpSession session = request.getSession();
String checkCodeGen = (String) session.getAttribute("checkCodeGen");
// 比对
if(!checkCodeGen.equalsIgnoreCase(checkCode)){
request.setAttribute("register_msg","验证码错误");
request.getRequestDispatcher("/register.jsp").forward(request,response);
// 不允许注册
return;
}
//2. 调用service 注册
boolean flag = service.register(user);
//3. 判断注册成功与否
if(flag){
//注册功能，跳转登陆页面
request.setAttribute("register_msg","注册成功，请登录");
request.getRequestDispatcher("/login.jsp").forward(request,response);
}else {
//注册失败，跳转到注册页面
request.setAttribute("register_msg","用户名已存在");
request.getRequestDispatcher("/register.jsp").forward(request,response);
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}//CheckCodeServlet.java
package com.itheima.web;
import com.itheima.util.CheckCodeUtil;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
@WebServlet("/checkCodeServlet")
public class CheckCodeServlet extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
// 生成验证码
ServletOutputStream os = response.getOutputStream();
String checkCode = CheckCodeUtil.outputVerifyImage(100, 50, os, 4);
// 存入Session
HttpSession session = request.getSession();
session.setAttribute("checkCodeGen",checkCode);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}//工具类 CheckCodeUtil.java
package com.itheima.util;
import javax.imageio.ImageIO;
import java.awt.*;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.*;
import java.util.Arrays;
import java.util.Random;
/**
* 生成验证码工具类
*/
public class CheckCodeUtil {
public static final String VERIFY_CODES = "123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
private static Random random = new Random();
public static void main(String[] args) throws IOException {
OutputStream fos = new FileOutputStream("d://a.jpg");
String checkCode = CheckCodeUtil.outputVerifyImage(100, 50, fos, 4);
System.out.println(checkCode);
}
/**
* 输出随机验证码图片流,并返回验证码值（一般传入输出流，响应response页面端，Web项目用的较多）
*
* @param width 图片宽度
* @param height 图片高度
* @param os 输出流
* @param verifySize 数据长度
* @return 验证码数据
* @throws IOException
*/
public static String outputVerifyImage(int width, int height, OutputStream os, int verifySize) throws IOException {
String verifyCode = generateVerifyCode(verifySize);
outputImage(width, height, os, verifyCode);
return verifyCode;
}
/**
* 使用系统默认字符源生成验证码
*
* @param verifySize 验证码长度
* @return
*/
public static String generateVerifyCode(int verifySize) {
return generateVerifyCode(verifySize, VERIFY_CODES);
}
/**
* 使用指定源生成验证码
*
* @param verifySize 验证码长度
* @param sources 验证码字符源
* @return
*/
public static String generateVerifyCode(int verifySize, String sources) {
// 未设定展示源的字码，赋默认值大写字母+数字
if (sources == null || sources.length() == 0) {
sources = VERIFY_CODES;
}
int codesLen = sources.length();
Random rand = new Random(System.currentTimeMillis());
StringBuilder verifyCode = new StringBuilder(verifySize);
for (int i = 0; i < verifySize; i++) {
verifyCode.append(sources.charAt(rand.nextInt(codesLen - 1)));
}
return verifyCode.toString();
}
/**
* 生成随机验证码文件,并返回验证码值 (生成图片形式，用的较少)
*
* @param w
* @param h
* @param outputFile
* @param verifySize
* @return
* @throws IOException
*/
public static String outputVerifyImage(int w, int h, File outputFile, int verifySize) throws IOException {
String verifyCode = generateVerifyCode(verifySize);
outputImage(w, h, outputFile, verifyCode);
return verifyCode;
}
/**
* 生成指定验证码图像文件
*
* @param w
* @param h
* @param outputFile
* @param code
* @throws IOException
*/
public static void outputImage(int w, int h, File outputFile, String code) throws IOException {
if (outputFile == null) {
return;
}
File dir = outputFile.getParentFile();
//文件不存在
if (!dir.exists()) {
//创建
dir.mkdirs();
}
try {
outputFile.createNewFile();
FileOutputStream fos = new FileOutputStream(outputFile);
outputImage(w, h, fos, code);
fos.close();
} catch (IOException e) {
throw e;
}
}
/**
* 输出指定验证码图片流
*
* @param w
* @param h
* @param os
* @param code
* @throws IOException
*/
public static void outputImage(int w, int h, OutputStream os, String code) throws IOException {
int verifySize = code.length();
BufferedImage image = new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
Random rand = new Random();
Graphics2D g2 = image.createGraphics();
g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
// 创建颜色集合，使用java.awt包下的类
Color[] colors = new Color[5];
Color[] colorSpaces = new Color[]{Color.WHITE, Color.CYAN,
Color.GRAY, Color.LIGHT_GRAY, Color.MAGENTA, Color.ORANGE,
Color.PINK, Color.YELLOW};
float[] fractions = new float[colors.length];
for (int i = 0; i < colors.length; i++) {
colors[i] = colorSpaces[rand.nextInt(colorSpaces.length)];
fractions[i] = rand.nextFloat();
}
Arrays.sort(fractions);
// 设置边框色
g2.setColor(Color.GRAY);
g2.fillRect(0, 0, w, h);
Color c = getRandColor(200, 250);
// 设置背景色
g2.setColor(c);
g2.fillRect(0, 2, w, h - 4);
// 绘制干扰线
Random random = new Random();
// 设置线条的颜色
g2.setColor(getRandColor(160, 200));
for (int i = 0; i < 20; i++) {
int x = random.nextInt(w - 1);
int y = random.nextInt(h - 1);
int xl = random.nextInt(6) + 1;
int yl = random.nextInt(12) + 1;
g2.drawLine(x, y, x + xl + 40, y + yl + 20);
}
// 添加噪点
// 噪声率
float yawpRate = 0.05f;
int area = (int) (yawpRate * w * h);
for (int i = 0; i < area; i++) {
int x = random.nextInt(w);
int y = random.nextInt(h);
// 获取随机颜色
int rgb = getRandomIntColor();
image.setRGB(x, y, rgb);
}
// 添加图片扭曲
shear(g2, w, h, c);
g2.setColor(getRandColor(100, 160));
int fontSize = h - 4;
Font font = new Font("Algerian", Font.ITALIC, fontSize);
g2.setFont(font);
char[] chars = code.toCharArray();
for (int i = 0; i < verifySize; i++) {
AffineTransform affine = new AffineTransform();
affine.setToRotation(Math.PI / 4 * rand.nextDouble() * (rand.nextBoolean() ? 1 : -1), (w / verifySize) * i + fontSize / 2, h / 2);
g2.setTransform(affine);
g2.drawChars(chars, i, 1, ((w - 10) / verifySize) * i + 5, h / 2 + fontSize / 2 - 10);
}
g2.dispose();
ImageIO.write(image, "jpg", os);
}
/**
* 随机颜色
*
* @param fc
* @param bc
* @return
*/
private static Color getRandColor(int fc, int bc) {
if (fc > 255) {
fc = 255;
}
if (bc > 255) {
bc = 255;
}
int r = fc + random.nextInt(bc - fc);
int g = fc + random.nextInt(bc - fc);
int b = fc + random.nextInt(bc - fc);
return new Color(r, g, b);
}
private static int getRandomIntColor() {
int[] rgb = getRandomRgb();
int color = 0;
for (int c : rgb) {
color = color << 8;
color = color | c;
}
return color;
}
private static int[] getRandomRgb() {
int[] rgb = new int[3];
for (int i = 0; i < 3; i++) {
rgb[i] = random.nextInt(255);
}
return rgb;
}
private static void shear(Graphics g, int w1, int h1, Color color) {
shearX(g, w1, h1, color);
shearY(g, w1, h1, color);
}
private static void shearX(Graphics g, int w1, int h1, Color color) {
int period = random.nextInt(2);
boolean borderGap = true;
int frames = 1;
int phase = random.nextInt(2);
for (int i = 0; i < h1; i++) {
double d = (double) (period >> 1)
* Math.sin((double) i / (double) period
+ (6.2831853071795862D * (double) phase)
/ (double) frames);
g.copyArea(0, i, w1, 1, (int) d, 0);
if (borderGap) {
g.setColor(color);
g.drawLine((int) d, i, 0, i);
g.drawLine((int) d + w1, i, w1, i);
}
}
}
private static void shearY(Graphics g, int w1, int h1, Color color) {
int period = random.nextInt(40) + 10; // 50;
boolean borderGap = true;
int frames = 20;
int phase = 7;
for (int i = 0; i < w1; i++) {
double d = (double) (period >> 1)
* Math.sin((double) i / (double) period
+ (6.2831853071795862D * (double) phase)
/ (double) frames);
g.copyArea(i, 0, 1, h1, 0, (int) d);
if (borderGap) {
g.setColor(color);
g.drawLine(i, (int) d, i, 0);
g.drawLine(i, (int) d + h1, i, h1);
}
}
}
}