9.会话跟踪技术(Cookie、Session)
会话跟踪技术(Cookie、Session)
笔记目录：(https://www.cnblogs.com/wenjie2000/p/16378441.html)
-
会话：用户打开浏览器，访问web服务器的资源，会话建立，直到有一方断开连接，会话结束。在一次会话中可以包含多次请求和响应
-
会话跟踪：一种维护浏览器状态的方法，服务器需要识别多次请求是否来自于同一浏览器，以便在同一次会话的多次请求间共享数据
-
HTTP协议是无状态的，每次浏览器向服务器请求时，服务器都会将该请求视为新的请求，因此我们需要会话跟踪技术来实现会话内数据共享
-
实现方式：
- 客户端会话跟踪技术：Cookie
- 服务端会话跟踪技术：Session
Cookie
Cookie基本使用
-
Cookie：客户端会话技术，将数据保存到客户端，以后每次请求都携带Cookie数据进行访问
-
Cookie基本使用
发送Cookie：
-
创建Cookie对象，设置数据
Cookie cookie = new Cookie("key","value"); -
发送Cookie到客户端：使用Response对象
response.addCookie(cookie);
Edge浏览器可以在 edge://settings/siteData 中查看到所有网站发回的Cookie数据
获取Cookie：
-
获取客户端携带的所有Cookie，使用request对象
Cookie[] cookies = request.getCookies(); -
遍历数组,获取每一个Cookie对象：
for(Cookie cookie: cookies){} -
使用Cookie对象方法获取数据
cookie.getName(); cookie.getValue();
-
Cookie原理
-
Cookie的实现是基于HTTP协议的
-
响应头：set-cookie
-
请求头：cookie
-
Cookie使用细节
-
Cookie存活时间
-
默认情况下，Cookie存储在浏览器内存中，当浏览器关闭，内存释放，则Cookie被销毁
-
cookie.setMaxAge(int seconds)：设置Cookie存活时间
- 正数：将Cookie写入浏览器所在电脑的硬盘，持久化存储。到时间自动删除（注意时间单位为妙）
- 负数：默认值，Cookie在当前浏览器内存中，当浏览器关闭，则Cookie被销毁
- 零：删除对应Cookie
//使用举例 Cookie cookie = new Cookie("username", "z"); cookie.setMaxAge(600);//设置保存600秒 response.addCookie(cookie);
-
-
Cookie存储中文
-
Cookie不能直接存储中文
-
如需要存储，则需要进行转码：URL编码
String value ="张三"; //URL编码 value = URLEncoder.encode(value, "UTF-8"); System.out.println("存储数据:"+value);//%E5%BC%AO%E4%B8%89 Cookie cookie = new Cookie("username", value); response.addCookie(cookie);//获取到value（%E5%BC%AO%E4%B8%89）后再对其进行解码 //URL解码 value = URLDecoder.decode(value,enc: "UTF-8"); System.out.println(value);//张三
-
Session
Session基本使用
-
服务端会话跟踪技术：将数据保存到服务端
-
JavaEE提供HttpSession接口，来实现一次会话的多次请求间数据共享功能
-
使用：
-
获取Session对象
HttpSession session = request.getSession(); -
Session对象功能：
void setAttribute(String name, Object o)：存储数据到session域中Object getAttribute(String name)：根据key，获取值void removeAttribute(String name)：根据key，删除该键值对
-
Session原理
-
Session是基于Cookie实现的
session的id会跟着cookie发送到浏览器，下次服务器获取session会先在cookie中查找是否存在id对应的session，如果有就直接用，如果没有再来创建
Session使用细节
-
Session钝化、活化：
- 服务器重启后，Session中的数据是否还在?
钝化：在服务器正常关闭后，Tomcat会自动将Session数据写入硬盘的文件中
活化：再次启动服务器后，从文件中加载数据到Session中
-
Seesion销毁：
-
默认情况下，无操作，30分钟自动销毁
<!--apache-tomcat-8.5.82\conf\web.xml--> <session-config> <session-timeout>30</session-timeout> </session-config> -
调用Session对象的invalidate()方法
HttpSession session = request.getSession(); session.invalidate();
-
小结
- Cookie和Session都是来完成一次会话内多次请求间数据共享的
- 区别：
- 存储位置：Cookie是将数据存储在客户端，Session将数据存储在服务端
- 安全性：Cookie不安全，Session安全
- 数据大小：Cookie最大3KB，Session无大小限制
- 存储时间：Cookie可以长期存储，Session默认30分钟
- 服务器性能：Cookie不占服务器资源，Session占用服务器资源
案例
登录注册案例
视频讲解（https://www.bilibili.com/video/BV1Qf4y1T7Hx?p=129）
如果要看视频，不要跟着一步步做，没有意义。可以看他做完后再自己完成
需求说明：
-
完成用户登录功能，如果用户勾选“记住用户”，则下次访问登录页面自动填充用户名密码
-
完成注册功能，并实现验证码功能
用户登录
记住用户(写Cookie)
-
如果用户勾选“记住用户”，则下次访问登陆页面自动填充用户名密码
-
如何自动填充用户名和密码?
-
将用户名和密码写入Cookie中，并且持久化存储Cookie ，下次访问浏览器会自动携带Cookie
-
在页面获取Cookie数据后，设置到用户名和密码框中：
${cookie.key.value}//key指存储在cookie中的键名称
-
-
何时写Cookie?
- 登录成功
- 用户勾选记住用户复选框
注册
-
注册功能：保存用户信息到数据库
-
验证码功能：（这里可以用现成的工具类com/itwen/util/CheckCodeUtil.java生成验证码图片）
-
展示验证码：展示验证码图片，并可以点击切换
-
验证码就是使用Java代码生成的一张图片
-
验证码作用：防止机器自动注册，攻击服务器
-
-
校验验证码：验证码填写不正确，则注册失败
-
判断程序生成的验证码和用户输入的验证码是否一样，如果不一样，则阻止注册
-
验证码图片访问和提交注册表单是两次请求，所以要将程序生成的验证码存入Session中
-
-
代码
文件结构
login-web
src\main
java\com\itwen
mapper
UserMapper.java
package com.itwen.mapper; import com.itwen.pojo.User; import org.apache.ibatis.annotations.Insert; import org.apache.ibatis.annotations.Param; import org.apache.ibatis.annotations.Select; public interface UserMapper { /** * 根据用户名和密码查找用户对象 * @param username * @param password * @return */ @Select("select * from tb_user where username=#{un} and password=#{pd}") public User selectUser(@Param("un") String username, @Param("pd") String password); /** * 根据用户名查找用户 * @param username * @return */ @Select("select * from tb_user where username=#{username}") public User selectByUsername(String username); /** * 添加用户 * @param user */ @Insert("insert into tb_user values (null,#{username},#{password})") public void add(User user); }pojo
User.java
package com.itwen.pojo; public class User { private long id; private String username; private String password; public User() { } public User(long id, String username, String password) { this.id = id; this.username = username; this.password = password; } public long getId() { return id; } public void setId(long 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 + '\'' + '}'; } }service
UserService.java
package com.itwen.service; import com.itwen.mapper.UserMapper; import com.itwen.pojo.User; import com.itwen.util.SqlSessionFactoryUtils; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; public class UserService { //2.1 获取sqlSessionFactory对象 SqlSessionFactory sqlSessionFactory = SqlSessionFactoryUtils.getSqlSessionFactory(); /** * 登录方法 * @param username * @param password * @return */ public User login(String username, String password) { //2.使用MyBatis查询(MyBatis部分学过) //2.2获取sqlSession对象 SqlSession sqlSession = sqlSessionFactory.openSession(); //2.3获取Mapper UserMapper mapper = sqlSession.getMapper(UserMapper.class); //2.4调用方法查询信息 User user = mapper.selectUser(username, password); //2.5释放资源 sqlSession.close(); return user; } /** * 用户注册 * @param user * @return 是否注册成功 */ public boolean register(User user) { //2.使用MyBatis查询(MyBatis部分学过) //2.2获取sqlSession对象 SqlSession sqlSession = sqlSessionFactory.openSession(); //2.3获取Mapper UserMapper mapper = sqlSession.getMapper(UserMapper.class); //2.4调用方法查询信息 User u = mapper.selectByUsername(user.getUsername()); if (u==null){ //用户不存在 //添加用户 mapper.add(user); sqlSession.commit(); } //2.5释放资源 sqlSession.close(); return u==null; } }util
CheckCodeUtil.java
package com.itwen.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); } } } }SqlSessionFactoryUtils.java
package com.itwen.util; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import java.io.IOException; import java.io.InputStream; public class SqlSessionFactoryUtils { private static SqlSessionFactory sqlSessionFactory; static { try { String resource = "mybatis-config.xml"; InputStream inputStream = Resources.getResourceAsStream(resource); sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); } catch (IOException e) { e.printStackTrace(); } } public static SqlSessionFactory getSqlSessionFactory() { return sqlSessionFactory; } }web
CheckCodeServlet.java
package com.itwen.web; import com.itwen.util.CheckCodeUtil; import javax.servlet.ServletException; import javax.servlet.ServletOutputStream; 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.FileOutputStream; import java.io.IOException; import java.io.OutputStream; @WebServlet("/checkCodeServlet") public class CheckCodeServlet extends HttpServlet { protected void doPost(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); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } }HelloServlet.java
package com.itwen.web; 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 java.io.IOException; @WebServlet("/HelloServlet") public class HelloServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.getRequestDispatcher("/helloUser.jsp").forward(request,response); } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } }LoginServlet.java
package com.itwen.web; import com.itwen.mapper.UserMapper; import com.itwen.pojo.User; import com.itwen.service.UserService; import com.itwen.util.SqlSessionFactoryUtils; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import javax.servlet.ServletException; import javax.servlet.annotation.WebServlet; import javax.servlet.http.*; import java.io.IOException; import java.io.InputStream; import java.io.PrintWriter; @WebServlet("/loginServlet") public class LoginServlet extends HttpServlet { private UserService service=new UserService(); @Override protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //1.接收用户名密码 String username = request.getParameter("username"); String password = request.getParameter("password"); String remember = request.getParameter("remember"); //2.调用service查询 User user = service.login(username, password); //3.判断user是否为空 if(user!=null){ //登录成功 //判断是否要记住账号密码 if("1".equals(remember)){ //勾选了 //创建cookie Cookie c_username = new Cookie("username", username); Cookie c_password = new Cookie("password", password); //cookie保存一周 c_username.setMaxAge(7*24*60*60); c_password.setMaxAge(7*24*60*60); 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); String contextPath = request.getContextPath(); response.sendRedirect(contextPath+"/HelloServlet"); }else { //登录失败 System.out.println("1111111111111111111111"); //存储错误信息到request request.setAttribute("login_msg","用户名或密码错误"); //跳转到登录界面 request.getRequestDispatcher("login.jsp").forward(request,response); } } @Override protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } }RegisterServlet.java
package com.itwen.web; import com.itwen.pojo.User; import com.itwen.service.UserService; 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("/registerServlet") public class RegisterServlet extends HttpServlet { private UserService service = new UserService(); protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { //判断验证码是否正确 String checkCode = request.getParameter("checkCode"); HttpSession session = request.getSession(); String checkCodeGen = (String) session.getAttribute("checkCodeGen"); if (!checkCodeGen.equals(checkCode)){ request.setAttribute("register_msg","验证码错误"); request.getRequestDispatcher("register.jsp").forward(request,response); return;//记得要return，否者程序会继续执行，不能进行forward转发。会报错 } //获取账号密码 String username = request.getParameter("username"); String password = request.getParameter("password"); User user = new User(); user.setUsername(username); user.setPassword(password); //调用service注册 boolean flag = service.register(user); //判断是否注册成功 if (flag==true){ //注册成功 //跳转到登录界面 request.setAttribute("register_msg","注册成功请登录"); request.getRequestDispatcher("login.jsp").forward(request,response); }else { //注册失败 //提示注册失败 request.setAttribute("register_msg","注册失败,该用户已存在"); request.getRequestDispatcher("register.jsp").forward(request,response); } } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); } }resources
com.itwen.mapper
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.itwen.mapper.UserMapper"> </mapper>mybatis-config.xml
<?xml version="1.0" encoding="UTF-8" ?> <!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN" "http://mybatis.org/dtd/mybatis-3-config.dtd"> <configuration> <!--起别名--> <typeAliases> <package name="com.itwen.pojo"/> </typeAliases> <!--设置连接数据库的环境--> <environments default="development"> <environment id="development"> <transactionManager type="JDBC"/> <dataSource type="POOLED"> <property name="driver" value="com.mysql.jdbc.Driver"/> <property name="url" value="jdbc:mysql://localhost:3306/db1"/> <property name="username" value="root"/> <property name="password" value="123456"/> </dataSource> </environment> </environments> <!--引入映射文件--> <mappers> <package name="com.itwen.mapper"/> </mappers> </configuration>webapp
helloUser.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>Title</title> </head> <body> <h1>${user.username},欢迎你</h1> </body> </html>login.jsp
<%@ page contentType="text/html;charset=UTF-8" language="java" %> <!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>登录界面</title> </head> <body> <h1>${login_msg} ${register_msg}</h1> <form action="/login-web/loginServlet" method="post" > 用户名：<br><input name="username" value="${cookie.username.value}"><br> 密码：<br><input type="password" name="password" value="${cookie.password.value}"><br> 记住：<input type="checkbox" name="remember" value="1"><br> <input type="submit" value="登录"> <a href="register.jsp">注册</a> </form> </body> </html>register.jsp
<%-- Created by IntelliJ IDEA. User: ZWJ Date: 2022/12/27 Time: 16:17 To change this template use File | Settings | File Templates. --%> <%@ page contentType="text/html;charset=UTF-8" language="java" %> <html> <head> <title>注册界面</title> </head> <body> <h1>${register_msg}</h1> <form action="/login-web/registerServlet" method="post"> 用户名：<br><input name="username"><br> 密码：<br><input type="password" name="password"><br> 验证码：<br><input name="checkCode"><img id="checkCodeImg" src="/login-web/checkCodeServlet"><br> <input type="submit" value="注册"> </form> <script> /*点击切换验证码图片*/ document.getElementById("checkCodeImg").onclick = function () { // 因为重复请求相同地址时，浏览器会认为已经做过了，不会刷新。所以需要在后面加上一个参数来保证地址有差异 document.getElementById("checkCodeImg").src = "/login-web/checkCodeServlet?" + new Date().getMilliseconds(); } </script> </body> </html>pom.xml
<?xml version="1.0" encoding="UTF-8"?> <project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion> <groupId>org.example</groupId> <artifactId>login-web</artifactId> <version>1.0-SNAPSHOT</version> <packaging>war</packaging> <dependencies> <dependency> <groupId>javax.servlet</groupId> <artifactId>javax.servlet-api</artifactId> <version>3.1.0</version> <scope>provided</scope><!--编译和测试环境有效，运行环境无效。因为tomcat自带了这个jar包，会冲突--> </dependency> <dependency> <groupId>org.mybatis</groupId> <artifactId>mybatis</artifactId> <version>3.5.7</version> </dependency> <dependency> <groupId>mysql</groupId> <artifactId>mysql-connector-java</artifactId> <version>5.1.9</version> </dependency> <dependency> <groupId>javax.servlet.jsp</groupId> <artifactId>jsp-api</artifactId> <version>2.2</version> <scope>provided</scope><!--因为tomcat自带了这个包--> </dependency> <dependency> <groupId>jstl</groupId> <artifactId>jstl</artifactId> <version>1.2</version> </dependency> <dependency> <groupId>taglibs</groupId> <artifactId>standard</artifactId> <version>1.1.2</version> </dependency> </dependencies> <build> <plugins> <plugin> <groupId>org.apache.tomcat.maven</groupId> <artifactId>tomcat7-maven-plugin</artifactId> <version>2.2</version> <!-- <configuration><!–配置（可选项）–> <port>80</port><!–访问端口号（默认8080）–> <path>/</path><!–项目访问路径（默认为项目名）–> </configuration>--> </plugin> </plugins> </build> </project>
