目录
一、 会话跟踪技术
二、Cookie（客户端）
2.1 Cookie的基本使用
@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");
//2.发送Cookie，response
response.addCookie(cookie);
}@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) {
String name = cookie.getName();
if("username".equals(name)){
//3.获取数据
String value = cookie.getValue();
System.out.println(name+" "+value);
break;
}
}
}2.2 Cookie原理
2.3 Cookie使用细节
@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：7天
cookie.setMaxAge(60*60*24*7);
//2.发送Cookie，response
response.addCookie(cookie);
}@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) {
String name = cookie.getName();
if("username".equals(name)){
//3.获取数据
String value = cookie.getValue();
//URL解码
value = URLDecoder.decode(value, "UTF-8");
System.out.println(name+" "+value);
break;
}
}
}三、Session（服务器端）
3.1 Session的基本使用
在Session中存储数据 ：
ublic class SessionDemo1 extends HttpServlet {
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//存储数据
//1.获取Session对象
HttpSession session = request.getSession();
//2.存储数据
session.setAttribute("username", "zs");
}从Session中获取数据：
@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();
//2.获取数据
Object username = session.getAttribute("username");
System.out.println(username);
}3.2 Session基本原理
3.3 Session使用细节
@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();
//Session销毁
session.invalidate();
//2.获取数据
Object username = session.getAttribute("username");
System.out.println(username);
}四、登录注册案例
4.1 用户登录
Dao层：
Mapper接口（）：
/**
* 根据用户名和密码查询用户对象
* @param username
* @param password
* @return
*/
@Select("select * from tb_user where username = #{username} and password = #{password}")
User select(@Param("username") String username,@Param("password") String password);user实体类：
public class User {
private Integer id;
private String username;
private String password;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getPassword() {
return password;
}
public void setPassword(String password) {
this.password = password;
}
@Override
public String toString() {
return "User{" +
"id=" + id +
", username='" + username + '\'' +
", password='" + password + '\'' +
'}';
}
}UserMapper.xml:
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.mapper.UserMapper">
</mapper>Service层：
/**
* 登录方法
* @param username
* @param password
* @return
*/
public User login(String username,String password){
SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();
//2. 获取SqlSession
SqlSession sqlSession = factory.openSession();
//3. 获取UserMapper
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
//4. 调用方法
User user = mapper.select(username, password);
//释放资源
sqlSession.close();
return user;
}Web层：
Servlet：
@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");
//2.调用Service查询
User user = service.login(username, password);
//3.判断
if (user != null){
//登陆成功，跳转到查询所有的BrandServlet
//将登陆成功后的user对象，存储到Session中
HttpSession session = request.getSession();
session.setAttribute("user", user);
//contextPath实现了动态跳转
String contextPath = request.getContextPath();
response.sendRedirect(contextPath+"/selectAllServlet");
}else{
//登录失败
//存储存储错误信息到request中
request.setAttribute("login_msg", "用户名或密码错误");
//跳转到login.jsp页面
request.getRequestDispatcher("/login.jsp").forward(request,response);
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}JSP页面：
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>login</title>
<link href="css/login.css" rel="stylesheet">
</head>
<body>
<div id="loginDiv" style="height: 350px">
<form action="/brand-demo/loginServlet" method="post" id="form">
<h1 id="loginMsg">LOGIN IN</h1>
<div id="errorMsg">${login_msg} ${register_msg}</div>
<p>Username:<input id="username" name="username" value="${cookie.username.value}" type="text"></p>
<p>Password:<input id="password" name="password" value="${cookie.password.value}" type="password"></p>
<p>Remember:<input id="remember" name="remember" value="1" type="checkbox"></p>
<div id="subDiv">
<input type="submit" class="button" value="login up">
<input type="reset" class="button" value="reset">
<a href="register.jsp">没有账号？</a>
</div>
</form>
</div>
</body>
</html>注意：
- 在Service中查到了用户信息和密码，要将该用户信息存到Session中，保证在本次会话过程中可以在页面用EL表达式在屏幕上动态输出用户信息
- 利用request的getContestPath方法获取当前Web项目的根路径，使用response.sendRedirect字符串拼接可动态获取当前的虚拟目录
- 用户登录的错误信息需要存在request域中，使之在本次请求有效，并将错误信息显示在登录页面
4.2 记住用户
//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){
//登陆成功，跳转到查询所有的BrandServlet
//判断用户是否勾选记住我,"1"写前面防止字符串空指针异常
if ("1".equals(remember)){
//勾选了，发送Cookie
//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Cookie
response.addCookie(c_username);
response.addCookie(c_password);
}
}@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){
//登陆成功，跳转到查询所有的BrandServlet
//判断用户是否勾选记住我,"1"写前面防止字符串空指针异常
if ("1".equals(remember)){
//勾选了，发送Cookie
//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Cookie
response.addCookie(c_username);
response.addCookie(c_password);
}
//将登陆成功后的user对象，存储到Session中
HttpSession session = request.getSession();
session.setAttribute("user", user);
//contextPath实现了动态跳转
String contextPath = request.getContextPath();
response.sendRedirect(contextPath+"/selectAllServlet");
}else{
//登录失败
//存储存储错误信息到request中
request.setAttribute("login_msg", "用户名或密码错误");
//跳转到login.jsp页面
request.getRequestDispatcher("/login.jsp").forward(request,response);
}
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
在login.jsp中
<p>Username:<input id="username" name="username" value="${cookie.username.value}" type="text"></p>
<p>Password:<input id="password" name="password" value="${cookie.password.value}" type="password"></p>
<p>Remember:<input id="remember" name="remember" value="1" type="checkbox"></p>注意：
- 判断用户是否勾选记住我,"1"写前面防止字符串空指针异常
if ("1".equals(remember)) - 在JSP中用EL表达式获取Cookie
4.3 注册功能
注册的基本功能实现：：
Dao层：
Mapper接口：
/**
* 根据用户名查询用户对象
* @param username
* @return
*/
@Select("select * from tb_user where username = #{username}")
User selectByUsername(String username);
/**
* 添加用户
* @param user
*/
@Insert("insert into tb_user values(null,#{username},#{password})")
void add(User user);Service层:
/**
* 注册方法
* @return
*/
public boolean register(User user){
//2. 获取SqlSession
SqlSession sqlSession = factory.openSession();
//3. 获取UserMapper
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
//4. 判断用户名是否存在
User u = mapper.selectByUsername(user.getUsername());
if(u == null){
// 用户名不存在，注册
mapper.add(user);
sqlSession.commit();
}
sqlSession.close();
return u == null;
}Web层：
register.jsp页面：
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>欢迎注册</title>
<link href="css/register.css" rel="stylesheet">
</head>
<body>
<div class="form-div">
<div class="reg-content">
<h1>欢迎注册</h1>
<span>已有帐号？</span> <a href="login.html">登录</a>
</div>
<form id="reg-form" action="/brand-demo/registerServlet" method="post">
<table>
<tr>
<td>用户名</td>
<td class="inputs">
<input name="username" type="text" id="username">
<br>
<span id="username_err" class="err_msg" >${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>
</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>Servlet:
@WebServlet("/registerServlet")
public class RegisterServlet extends HttpServlet {
private UserService service = new UserService();
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.获取对应的用户名和数据
String username = request.getParameter("username");
String password = request.getParameter("password");
User user = new User();
user.setUsername(username);
user.setPassword(password);
//2.调用Service注册
boolean flag = service.register(user);
//3.判断注册成功与否
if(flag){
//注册成功，跳转登录页面
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);
}
}4.4 注册----验证码功能
验证码工具类：
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);
}
}
}
}
验证码Servlet：
@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);
}
}验证验证码：
@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);
}
}验证码jsp页面代码：
<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><script>
document.getElementById("changeImg").onclick = function () {
document.getElementById("checkCodeImg").src = "/brand-demo/checkCodeServlet?"+new Date().getMilliseconds();
}
</script>注意：在绑定单击事件获取src时，为了防止缓存，需要在原虚拟目录上拼接上时间获得新的虚拟目录，才能保证虚拟目录不重复