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牧风的在wordpress,台州网站优化公司,用网站做淘客怎么做,如何做好网站内容优化JavaWeb入门5.0 1. JSP1.1 JSP快速入门1.2 JSP原理1.3 JSP脚本1.3.1 JSP缺点 1.4 EL 表达式1.5 JSTL 标签1.5.1 JSTL 快速入门1.5.1 - I JSTL标签if1.5.1 - II JSTL标签forEach 1.6 MVC模式1.7 三层架构1.8 实现案例1.8.1 环境准备1.8.2 查询所有1.8.3 添加数据1.8.4 修改1.8.4…

JavaWeb入门5.0

1. JSP
- 1.1 JSP快速入门
- 1.2 JSP原理
- 1.3 JSP脚本
- - 1.3.1 JSP缺点
- 1.4 EL 表达式
- 1.5 JSTL 标签
- - 1.5.1 JSTL 快速入门
  - - 1.5.1 - I JSTL标签if
    - 1.5.1 - II JSTL标签forEach
- 1.6 MVC模式
- 1.7 三层架构
- 1.8 实现案例
- - 1.8.1 环境准备
  - 1.8.2 查询所有
  - 1.8.3 添加数据
  - 1.8.4 修改
  - - 1.8.4 - I 修改回显数据
    - 1.8.4 - II 修改数据
2. 会话跟踪技术
- 2.1 Cookie
- - 2.1.1 Cookie基本使用
  - 2.1.2 Cookie原理
  - 2.1.3 Cookie使用细节
- 2.2 Session
- - 2.2.1 Session基本使用
  - 2.2.2 Session原理
  - 2.2.3 Session使用细节
- 2.3 小结
- 2.4 案例
- - 2.4.1 用户登录
  - 2.4.2 记住用户
  - - 2.4.2 - I 写cookie
    - 2.4.2 - II 获取cookie
  - 2.4.3 用户注册
  - 2.4.4 验证码
  - - 2.4.4 - I 校验验证码

1. JSP

概念：Java Server Pags，java服务端页面

一种动态的网页接收，其中即可以定义HTML、JS、CSS等静态内容，还可以定义Java代码的动态内容
JSP = HTML + Java

1.1 JSP快速入门

导入JSP坐标

    <dependency><groupId>javax.servlet.jsp</groupId><artifactId>jsp-api</artifactId><version>2.2</version><scope>provided</scope></dependency>

创建JSP文件
编写HTML标签和Java代码

案例：

<html>
<head><title>Title</title>
</head>
<body><h1>JSP,hello</h1><%System.out.println("hello jsp");%>
</body>
</html>

在这里插入图片描述

1.2 JSP原理

JSP本质上就是一个Servlet
JSP在被访问时，由JSP容器(Tomcat)将其转换为Java文件(Servlet)，在由JSP容器(Tomcat)将其编译，最终对外提供服务的其实就是这个字节码文件

1.3 JSP脚本

JSP脚本用于在JSP页面内定义Java代码.
JSP脚本分类:
1、 <%...%>:内容会直接放到_jspService()方法之中
2、<%=...%>:内容会放到out.print()中，作为out.print()的参数
3、<%!..%>:内容会放到_jspService()方法之外，被类直接包含

例子：
注意使用maven插件的tomcat7运行时最好对应的jdk版本为1.8，如果jdk版本太高可能会出现jsp编译不了的情况（500报错之一）
解决方案：

- 1.在设置里面，Build->创建工具->Maven->运行程序下找到JRE条件jdk版本
- 2.自行在创建项目时使用低版本的jdk
- 3.具体分析java语法变换，下例情况去掉System

<%--Created by IntelliJ IDEA.User: 19148Date: 2023/7/31Time: 9:46To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head><title>Title</title>
</head>
<body><h1>JSP,hello</h1><%out.println("hello,jsp");int i = 3;%><%="hello"%><%=i%><%!void show(){}String name = "zhangsan";%>
</body>
</html>

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练习：
在这里插入图片描述
Brand类：

package com.itheima.pojo;/*** 品牌实体类*/public class Brand {// id 主键private Integer id;// 品牌名称private String brandName;// 企业名称private String companyName;// 排序字段private Integer ordered;// 描述信息private String description;// 状态：0：禁用  1：启用private Integer status;public Brand() {}public Brand(Integer id, String brandName, String companyName, String description) {this.id = id;this.brandName = brandName;this.companyName = companyName;this.description = description;}public Brand(Integer id, String brandName, String companyName, Integer ordered, String description, Integer status) {this.id = id;this.brandName = brandName;this.companyName = companyName;this.ordered = ordered;this.description = description;this.status = status;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getBrandName() {return brandName;}public void setBrandName(String brandName) {this.brandName = brandName;}public String getCompanyName() {return companyName;}public void setCompanyName(String companyName) {this.companyName = companyName;}public Integer getOrdered() {return ordered;}public void setOrdered(Integer ordered) {this.ordered = ordered;}public String getDescription() {return description;}public void setDescription(String description) {this.description = description;}public Integer getStatus() {return status;}public void setStatus(Integer status) {this.status = status;}@Overridepublic String toString() {return "Brand{" +"id=" + id +", brandName='" + brandName + '\'' +", companyName='" + companyName + '\'' +", ordered=" + ordered +", description='" + description + '\'' +", status=" + status +'}';}
}

brand.jsp:

<%@ page import="com.itheima.pojo.Brand" %>
<%@ page import="java.util.List" %>
<%@ page import="java.util.ArrayList" %><%--Created by IntelliJ IDEA.User: 19148Date: 2023/8/1Time: 12:19To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %><%//查询数据库List<Brand> brands = new ArrayList<Brand>();brands.add(new Brand(1,"三只松鼠","三只松鼠",100,"三只松鼠，好吃不上火",1));brands.add(new Brand(2,"优衣库","优衣库",200,"优衣库，服适人生",0));brands.add(new Brand(3,"小米","小米科技有限公司",1000,"为发烧而生",1));
%><!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<input type="button" value="新增"><br>
<hr>
<table border="1" cellspacing="0" width="800"><tr><th>序号</th><th>品牌名称</th><th>企业名称</th><th>排序</th><th>品牌介绍</th><th>状态</th><th>操作</th></tr><%for (int i = 0; i < brands.size(); i++) {Brand brand = brands.get(i);%><tr align="center"><td><%=brand.getId()%></td><td><%=brand.getBrandName()%></td><td><%=brand.getCompanyName()%></td><td><%=brand.getOrdered()%></td><td><%=brand.getDescription()%></td><%if(brand.getStatus()==1){//显示启用%><td><%="启用"%></td><%}else {//显示禁用%><td><%="禁用"%></td><%}%><td><a href="#">修改</a> <a href="#">删除</a></td></tr><%}%></table></body>
</html>

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1.3.1 JSP缺点

在这里插入图片描述

由于JSP页面内，既可以定义HTML标签，又可以定义Java代码，造成了以下问题:

书写麻烦:特别是复杂的页面
阅读麻烦
复杂度高:运行需要依赖于各种环境，JRE，JSP容器，JavaEE…
占内存和磁盘:JSP会自动生成.java和.class文件占磁盘，运行的是.class文件占内存
调试困难:出错后，需要找到自动生成的.java文件进行调试
不利于团队协作:前端人员不会Java，后端人员不精HTML
…

演变过程：
在这里插入图片描述

1.4 EL 表达式

Expression Language表达式语言，用于简化JSP页面内的Java代码

主要功能：获取数据

语法：${expression}
${brands}：获取域中存储的key为brands的数据

JavaWeb中的四大域对象:

page:当前页面有效
request:当前请求有效
session:当前会话有效
application:当前应用有效

例子：
ServletDemo1：

@WebServlet("/demo1")
public class ServletDemo1 extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//1.准备数据List<Brand> brands = new ArrayList<Brand>();brands.add(new Brand(1,"三只松鼠","三只松鼠",100,"三只松鼠，好吃不上火",1));brands.add(new Brand(2,"优衣库","优衣库",200,"优衣库，服适人生",0));brands.add(new Brand(3,"小米","小米科技有限公司",1000,"为发烧而生",1));//2.储存到request域中request.setAttribute("brands",brands);//3.转发到el-demo.jsprequest.getRequestDispatcher("/el-demo.jsp").forward(request,response);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

el-demo.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<html>
<head><title>Title</title>
</head>
<body>${brands}</body>
</html>

如果只是显示 ${brands}的话，在头部加上isELIgnored="false"即可
在这里插入图片描述

el表达式获取数据，会依次从这4个域中寻找，直到找到为止

1.5 JSTL 标签

JSP标准标签库(Jsp Standarded Tag Library)，使用标签取代JSP页面上的Java代码

例如：

<c:if test="${flag ==1}">
男
</c:if>
<c:if test="${flag == 2}">
女
</c:if>

在这里插入图片描述

1.5.1 JSTL 快速入门

导入坐标

<dependency><groupId>jstl</groupId><artifactId>jstl<lartifactId><version>1.2</version>
</dependency>
<dependency><groupId>taglibs</groupId><artifactId>standard</artifactId><version>1.1.2</version>
</dependency>

在JSP页面上引入JSTL标签库

<%@ taglib prefix= "c" uri= "http://java.sun.com/jsp/jstl/core" %>

使用
- <C:if>

1.5.1 - I JSTL标签if

例子：
ServletDemo1类修改部分：
在这里插入图片描述
jstl-if.jsp：

<%@ page contentType="text/html;charset=UTF-8" language="java"  isELIgnored="false" %>
<html>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%><head><title>Title</title>
</head>
<body>
<%--c:if 来完成逻辑判断，替换java if else
--%><%--    <c:if test="true">--%>
<%--        <h1>true</h1>--%>
<%--    </c:if>--%>
<%--    <c:if test="false">--%>
<%--        <h1>false</h1>--%>
<%--    </c:if>--%><c:if test="${status ==1}">启用</c:if><c:if test="${status ==0}">禁用</c:if>
</body>
</html>

显示如果空白的话，添加：isELIgnored=“false”
在这里插入图片描述

1.5.1 - II JSTL标签forEach

<c:forEach>：相当于for循环

items：被遍历的容器
var：遍历产生的临时变量
varStatus：遍历状态对象
count：从1开始遍历的数字
status：从0开始遍历的数字

例子：

<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<input type="button" value="新增"><br>
<hr>
<table border="1" cellspacing="0" width="800"><tr><th>序号</th><th>品牌名称</th><th>企业名称</th><th>排序</th><th>品牌介绍</th><th>状态</th><th>操作</th></tr><c:forEach items="${brands}" var="brand" varStatus="status"><tr align="center">
<%--      <td>${brand.id}</td>--%><td>${status.count}</td><td>${brand.brandName}</td><td>${brand.companyName}</td><td>${brand.ordered}</td><td>${brand.description}</td><c:if test="${brand.status==1}"><td>启用</td></c:if><c:if test="${brand.status != 1}"><td>禁用</td></c:if><td><a href="#">修改</a> <a href="#">删除</a></td></tr></c:forEach></table></body>
</html>

在这里插入图片描述

begin：开始数
end：结束数
step：步长

例子：

<c:forEach begin="1" end="10" step="1" var="i">
<%--  ${i}<br>--%><a href="#">${i}</a>
</c:forEach>

在这里插入图片描述

1.6 MVC模式

MVC是一种分层开发的模式，其中:

M: Model，业务模型，处理业务
V: View，视图，界面展示
C: Controller，控制器，处理请求，调用模型和视图

MVC好处：

职责单一，互不影响
有利于分工协作
有利于组件重用

1.7 三层架构

数据访问层：对数据库的CRUD基本操作
业务逻辑层：对业务逻辑进行封装，组合数据访问层层中基本功能，形成复杂的业务逻辑功能
表现层：接收请求，封装数据，调用业务逻辑层，响应数据

MVC和三层架构的区别：

在这里插入图片描述

1.8 实现案例

在这里插入图片描述

1.8.1 环境准备

在这里插入图片描述

核心配置文件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>brand-demo</artifactId><version>1.0-SNAPSHOT</version><packaging>war</packaging><properties><maven.compiler.source>17</maven.compiler.source><maven.compiler.target>17</maven.compiler.target></properties><dependencies>
<!--        mybatis--><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.5</version></dependency><!--        mysql--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.30</version></dependency><!--        servlet--><dependency><groupId>javax.servlet</groupId><artifactId>javax.servlet-api</artifactId><version>3.1.0</version><scope>provided</scope></dependency><!--        jsp--><dependency><groupId>javax.servlet.jsp</groupId><artifactId>jsp-api</artifactId><version>2.2</version><scope>provided</scope></dependency><!--        jstl--><dependency><groupId>jstl</groupId><artifactId>jstl</artifactId><version>1.2</version></dependency><!--        standard标准标签库--><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></plugin></plugins></build>
</project>

创建目录结构包：
数据库的创建：

-- 删除tb_brand表
drop table if exists tb_brand;
-- 创建tb_brand表
create table tb_brand
(-- id 主键id           int primary key auto_increment,-- 品牌名称brand_name   varchar(20),-- 企业名称company_name varchar(20),-- 排序字段ordered      int,-- 描述信息description  varchar(100),-- 状态：0：禁用  1：启用status       int
);
-- 添加数据
insert into tb_brand (brand_name, company_name, ordered, description, status)
values ('三只松鼠', '三只松鼠股份有限公司', 5, '好吃不上火', 0),('华为', '华为技术有限公司', 100, '华为致力于把数字世界带入每个人、每个家庭、每个组织，构建万物互联的智能世界', 1),('小米', '小米科技有限公司', 50, 'are you ok', 1);SELECT * FROM tb_brand;

pojo下的Brand实体类

package com.itheima.pojo;/*** 品牌实体类*/public class Brand {// id 主键private Integer id;// 品牌名称private String brandName;// 企业名称private String companyName;// 排序字段private Integer ordered;// 描述信息private String description;// 状态：0：禁用  1：启用private Integer status;public Brand() {}public Brand(Integer id, String brandName, String companyName, String description) {this.id = id;this.brandName = brandName;this.companyName = companyName;this.description = description;}public Brand(Integer id, String brandName, String companyName, Integer ordered, String description, Integer status) {this.id = id;this.brandName = brandName;this.companyName = companyName;this.ordered = ordered;this.description = description;this.status = status;}public Integer getId() {return id;}public void setId(Integer id) {this.id = id;}public String getBrandName() {return brandName;}public void setBrandName(String brandName) {this.brandName = brandName;}public String getCompanyName() {return companyName;}public void setCompanyName(String companyName) {this.companyName = companyName;}public Integer getOrdered() {return ordered;}public void setOrdered(Integer ordered) {this.ordered = ordered;}public String getDescription() {return description;}public void setDescription(String description) {this.description = description;}public Integer getStatus() {return status;}public void setStatus(Integer status) {this.status = status;}@Overridepublic String toString() {return "Brand{" +"id=" + id +", brandName='" + brandName + '\'' +", companyName='" + companyName + '\'' +", ordered=" + ordered +", description='" + description + '\'' +", status=" + status +'}';}
}

mybatis-config.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configurationPUBLIC "-//mybatis.org//DTD Config 3.0//EN""http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration><!--起别名--><typeAliases><package name="com.itheima.pojo"/></typeAliases><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:///db1?useSSL=false&amp;useServerPrepStmts=true"/><property name="username" value="root"/><property name="password" value="root"/></dataSource></environment></environments><mappers><!--扫描mapper--><package name="com.itheima.mapper"/></mappers>
</configuration>

BrandMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.mapper.BrandMapper"></mapper>

BrandMapper.java

package com.itheima.mapper;public interface BrandMapper {
}

目录展示：
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1.8.2 查询所有

在这里插入图片描述

brand.jsp

<%--Created by IntelliJ IDEA.User: 19148Date: 2023/8/2Time: 9:59To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<input type="button" value="新增"><br>
<hr>
<table border="1" cellspacing="0" width="80%"><tr><th>序号</th><th>品牌名称</th><th>企业名称</th><th>排序</th><th>品牌介绍</th><th>状态</th><th>操作</th></tr><c:forEach items="${brands}" var="brand" varStatus="status"><tr align="center">
<%--      <td>${brand.id}</td>--%><td>${status.count}</td><td>${brand.brandName}</td><td>${brand.companyName}</td><td>${brand.ordered}</td><td>${brand.description}</td><c:if test="${brand.status==1}"><td>启用</td></c:if><c:if test="${brand.status != 1}"><td>禁用</td></c:if><td><a href="#">修改</a> <a href="#">删除</a></td></tr></c:forEach></table></body>
</html>

BrandMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.mapper.BrandMapper"><resultMap id="brandResultMap" type="brand"><result column="brand_name" property="brandName"></result><result column="company_name" property="companyName"></result></resultMap>
</mapper>

BrandMapper.java

package com.itheima.mapper;import com.itheima.pojo.Brand;
import org.apache.ibatis.annotations.ResultMap;
import org.apache.ibatis.annotations.Select;import java.util.List;public interface BrandMapper {//查询所有@Select("select * from tb_brand")@ResultMap("brandResultMap")List<Brand> selectAll();
}

BrandService.java

public class BrandService {SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();//查询所有功能public List<Brand> selectAll(){//调用BrandMapper.selectAll()//2.获取SqlSessionSqlSession sqlSession = factory.openSession();//3.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//4.调用方法List<Brand> brands = mapper.selectAll();sqlSession.close();return brands;}
}

index.html

<!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body><a href="/brand-demo/selectAllServlet">查询所有</a>
</body>
</html>

SqlSessionFactoryUtils 类：

ublic class SqlSessionFactoryUtils {private static SqlSessionFactory sqlSessionFactory;static {//静态代码块会随着类的加载而自动执行，且只执行一次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;}
}

selectAllServlet：

@WebServlet("/selectAllServlet")
public class selectAllServlet extends HttpServlet {private BrandService service = new BrandService();@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//1.调用BrandService完成查询List<Brand> brands = service.selectAll();//2.存入request域中request.setAttribute("brands",brands);//3.转发到brand.jsprequest.getRequestDispatcher("/brand.jsp").forward(request,response);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

在这里插入图片描述

1.8.3 添加数据

在这里插入图片描述

brand.jsp：

<%--Created by IntelliJ IDEA.User: 19148Date: 2023/8/2Time: 9:59To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %><!DOCTYPE html>
<html lang="en">
<head><meta charset="UTF-8"><title>Title</title>
</head>
<body>
<input type="button" value="新增" id="add"><br>
<hr>
<table border="1" cellspacing="0" width="80%"><tr><th>序号</th><th>品牌名称</th><th>企业名称</th><th>排序</th><th>品牌介绍</th><th>状态</th><th>操作</th></tr><c:forEach items="${brands}" var="brand" varStatus="status"><tr align="center">
<%--      <td>${brand.id}</td>--%><td>${status.count}</td><td>${brand.brandName}</td><td>${brand.companyName}</td><td>${brand.ordered}</td><td>${brand.description}</td><c:if test="${brand.status==1}"><td>启用</td></c:if><c:if test="${brand.status != 1}"><td>禁用</td></c:if><td><a href="#">修改</a> <a href="#">删除</a></td></tr></c:forEach></table><script>document.getElementById("add").onclick = function (){location.href="/brand-demo/addBrand.jsp ";}
</script></body>
</html>

BrandMapper.java

public interface BrandMapper {//查询所有@Select("select * from tb_brand")@ResultMap("brandResultMap")List<Brand> selectAll();@Insert("insert into tb_brand values(null,#{brandName},#{companyName},#{ordered},#{description},#{status})")void add(Brand brand);
}

BrandService.java

public class BrandService {SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();//查询所有功能public List<Brand> selectAll(){//调用BrandMapper.selectAll()//2.获取SqlSessionSqlSession sqlSession = factory.openSession();//3.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//4.调用方法List<Brand> brands = mapper.selectAll();sqlSession.close();return brands;}public void add(Brand brand){//2.获取SqlSessionSqlSession sqlSession = factory.openSession();//3.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//4.调用方法mapper.add(brand);//提交事务sqlSession.commit();sqlSession.close();}}

addBrand.jsp

<%--Created by IntelliJ IDEA.User: 19148Date: 2023/8/2Time: 21:22To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %><!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><title>添加品牌</title>
</head>
<body>
<h3>添加品牌</h3>
<form action="/brand-demo/AddServlet" method="post">品牌名称：<input name="brandName"><br>企业名称：<input name="companyName"><br>排序：<input name="ordered"><br>描述信息：<textarea rows="5" cols="20" name="description"></textarea><br>状态：<input type="radio" name="status" value="0">禁用<input type="radio" name="status" value="1">启用<br><input type="submit" value="提交">
</form>
</body>
</html>

AddServlet.java

@WebServlet("/AddServlet")
public class AddServlet extends HttpServlet {private BrandService service = new BrandService();@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//处理post请求乱码问题request.setCharacterEncoding("utf-8");//1.结束表单提交的数据，封装为一个Brand妒忌心String brandName = request.getParameter("brandName");String companyName = request.getParameter("companyName");String ordered = request.getParameter("ordered");String description = request.getParameter("description");String status = request.getParameter("status");//封装为一个Brand对象Brand brand = new Brand();brand.setBrandName(brandName);brand.setCompanyName(companyName);brand.setOrdered(Integer.parseInt(ordered));brand.setDescription(description);brand.setStatus(Integer.parseInt(status));//2.调用service 完成添加操作service.add(brand);//3.转发到查询所有Servletrequest.getRequestDispatcher("/selectAllServlet").forward(request,response);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

在这里插入图片描述

1.8.4 修改

在这里插入图片描述

1.8.4 - I 修改回显数据

在这里插入图片描述

BrandMapper.java

public interface BrandMapper {//查询所有@Select("select * from tb_brand")@ResultMap("brandResultMap")List<Brand> selectAll();@Insert("insert into tb_brand values(null,#{brandName},#{companyName},#{ordered},#{description},#{status})")void add(Brand brand);//根据id查询@Select("select * from tb_brand where id = #{id}")@ResultMap("brandResultMap")Brand selectById(int id);}

update.jsp

<%--Created by IntelliJ IDEA.User: 19148Date: 2023/8/2Time: 21:22To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false"%>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%><!DOCTYPE html>
<html lang="en"><head><meta charset="UTF-8"><title>修改品牌</title>
</head>
<body>
<h3>修改品牌</h3>
<form action="/brand-demo/AddServlet" method="post">品牌名称：<input name="brandName" value="${brand.brandName}"><br>企业名称：<input name="companyName" value="${brand.companyName}"><br>排序：<input name="ordered" value="${brand.ordered}"><br>描述信息：<textarea rows="5" cols="20" name="description"> value="${brand.description}"</textarea><br>状态：<c:if test="${brand.status == 0}"><input type="radio" name="status" value="0" checked>禁用<input type="radio" name="status" value="1">启用<br></c:if><c:if test="${brand.status == 1}"><input type="radio" name="status" value="0">禁用<input type="radio" name="status" value="1"  checked>启用<br></c:if><input type="submit" value="提交">
</form>
</body>
</html>

selectByIdServlet

WebServlet("/selectByIdServlet")
public class selectByIdServlet extends HttpServlet {private BrandService service = new BrandService();@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//1.接收idString id = request.getParameter("id");//2.调用serivce查询Brand brand = service.selectById(Integer.parseInt(id));//3.存储到request中request.setAttribute("brand",brand);//4.转发到update.jsprequest.getRequestDispatcher("/update.jsp").forward(request,response);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

BrandService

public class BrandService {SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();//查询所有功能public List<Brand> selectAll(){//调用BrandMapper.selectAll()//2.获取SqlSessionSqlSession sqlSession = factory.openSession();//3.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//4.调用方法List<Brand> brands = mapper.selectAll();sqlSession.close();return brands;}public void add(Brand brand){//2.获取SqlSessionSqlSession sqlSession = factory.openSession();//3.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//4.调用方法mapper.add(brand);//提交事务sqlSession.commit();sqlSession.close();}//根据id查询public Brand selectById(int id){//调用BrandMapper.selectAll()//2.获取SqlSessionSqlSession sqlSession = factory.openSession();//3.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//4.调用方法Brand brand = mapper.selectById(id);sqlSession.close();return brand;}
}

在这里插入图片描述

1.8.4 - II 修改数据

在这里插入图片描述

BrandMapper.java

public interface BrandMapper {//查询所有@Select("select * from tb_brand")@ResultMap("brandResultMap")List<Brand> selectAll();@Insert("insert into tb_brand values(null,#{brandName},#{companyName},#{ordered},#{description},#{status})")void add(Brand brand);//根据id查询@Select("select * from tb_brand where id = #{id}")@ResultMap("brandResultMap")Brand selectById(int id);//修改@Update("update tb_brand set brand_name = #{brandName},company_name=#{companyName},ordered=#{ordered},description=#{description},status=#{status} where id=#{id}")void update(Brand brand);
}

updateService.java

@WebServlet("/updateServlet")
public class updateServlet extends HttpServlet {private BrandService service = new BrandService();@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//处理post请求乱码问题request.setCharacterEncoding("utf-8");//1.结束表单提交的数据，封装为一个Brand妒忌心String id = request.getParameter("id");String brandName = request.getParameter("brandName");String companyName = request.getParameter("companyName");String ordered = request.getParameter("ordered");String description = request.getParameter("description");String status = request.getParameter("status");//封装为一个Brand对象Brand brand = new Brand();brand.setId(Integer.parseInt(id));brand.setBrandName(brandName);brand.setCompanyName(companyName);brand.setOrdered(Integer.parseInt(ordered));brand.setDescription(description);brand.setStatus(Integer.parseInt(status));//2.调用service 完成添加操作service.update(brand);//3.转发到查询所有Servletrequest.getRequestDispatcher("/selectAllServlet").forward(request,response);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

BrandService.java

public class BrandService {SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();//查询所有功能public List<Brand> selectAll(){//调用BrandMapper.selectAll()//2.获取SqlSessionSqlSession sqlSession = factory.openSession();//3.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//4.调用方法List<Brand> brands = mapper.selectAll();sqlSession.close();return brands;}//添加public void add(Brand brand){//2.获取SqlSessionSqlSession sqlSession = factory.openSession();//3.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//4.调用方法mapper.add(brand);//提交事务sqlSession.commit();sqlSession.close();}//根据id查询public Brand selectById(int id){//调用BrandMapper.selectAll()//2.获取SqlSessionSqlSession sqlSession = factory.openSession();//3.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//4.调用方法Brand brand = mapper.selectById(id);sqlSession.close();return brand;}//添加public void update(Brand brand){//2.获取SqlSessionSqlSession sqlSession = factory.openSession();//3.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//4.调用方法mapper.update(brand);//提交事务sqlSession.commit();sqlSession.close();}}

在这里插入图片描述

2. 会话跟踪技术

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，以便于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

2.1 Cookie

2.1.1 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

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);

例如：

@WebServlet("/aServlet")
public class aServlet extends HttpServlet {@Overrideprotected 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.responseresponse.addCookie(cookie);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

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.getName();

使用Cookie对象方法获取数据

cookie.getName();

cookie.getValue();

例子：

@WebServlet("/bServlet")
public class bServlet extends HttpServlet {@Overrideprotected 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();System.out.println(name+":"+value);break;}}}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

在这里插入图片描述
接收aServlet的cookie

2.1.2 Cookie原理

cookie的实现是基于HTTP协议的：

响应头：set-cookie
请求头：cookie

2.1.3 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
setMaxAge(int seconds):设置Cookie存活时间
- 1、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
- 2、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
- 3、零：删除对应Cookie

例子：

@WebServlet("/aServlet")
public class aServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//发送cookie//1.创建cookie对象Cookie cookie = new Cookie("username", "vanwot");//设置存活时间 7天cookie.setMaxAge((60*60*24*7));//2.发送Cookie.responseresponse.addCookie(cookie);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

在这里插入图片描述

Cookie存储中文：

Cookie不能直接存储中文
如果需要存储，则需要进行转码：URL编码

//编码value = URLDecoder.encode(value,"UTF-8");
//解码value = URLDecoder.decode(value,"UTF-8");

例子：
aServelt：

@WebServlet("/aServlet")
public class aServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//发送cookie//1.创建cookie对象String value= "麻瓜";//URL编码value = URLEncoder.encode(value,"utf-8");System.out.println("储存数据："+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.responseresponse.addCookie(cookie);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

bServlet：

@WebServlet("/bServlet")
public class bServlet extends HttpServlet {@Overrideprotected 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();System.out.println(name+":"+value);//URL解码value = URLDecoder.decode(value,"utf-8");System.out.println(name+":"+value);break;}}}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

在这里插入图片描述

2.2 Session

2.2.1 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

例子：
SessionDemo1：

@WebServlet("/demo1")
public class SessionDemo1 extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//存储到Session中//1.获取Session对象HttpSession session = request.getSession();//2.存储数据session.setAttribute("username","vanwot");}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

SessionDemo2：

@WebServlet("/demo2")
public class SessionDemo2 extends HttpServlet {@Overrideprotected 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);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

在这里插入图片描述

2.2.2 Session原理

Session是基于Cookie实现的
在这里插入图片描述

2.2.3 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
- 配置在web-xml文件中

<session-config><session-timeout>30</session-timeout>
</session-config>

调用Session对象的invalidate()方法

2.3 小结

Cookie和Session都是完成一次会话内多次请求间数据共享的

其区别：

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

2.4 案例

在这里插入图片描述

2.4.1 用户登录

在这里插入图片描述
在brand-demo的webapp下导入原来的：

UserMapper：

public interface UserMapper {/*** 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);/*** 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);
}

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;}@Overridepublic String toString() {return "User{" +"id=" + id +", username='" + username + '\'' +", password='" + password + '\'' +'}';}
}

UserMapper.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.mapper.UserMapper"></mapper>

UserService:

public class UserService {SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();//登录方法public User login(String username,String password){//2.获取SqlSessionSqlSession sqlSession = factory.openSession();//3.获取UserMapperUserMapper mapper = sqlSession.getMapper(UserMapper.class);//4.调用方法User user = mapper.select(username, password);sqlSession.close();return user;}
}

loginServlet：

@WebServlet("/loginServlet")
public class loginServlet extends HttpServlet {private UserService service = new UserService();@Overrideprotected 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){//登录成功，跳转到查询所有的BrandServlet//将登录成功后的user对象，储存到Session中HttpSession session = request.getSession();session.setAttribute("user",user);String contextPath = request.getContextPath();response.sendRedirect(contextPath+"/selectAllServlet");}else {//登录失败//存储错误信息到requestrequest.setAttribute("login_msg","用户名或密码错误");//跳转到login.jsprequest.getRequestDispatcher("/login.jsp").forward(request,response);}}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

用户名和密码错误时：
在这里插入图片描述
正确时：

2.4.2 记住用户

2.4.2 - I 写cookie

在这里插入图片描述

<%--Created by IntelliJ IDEA.User: 19148Date: 2023/8/4Time: 23:39To change this template use File | Settings | File Templates.
--%>
<%@ 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" id="form"><h1 id="loginMsg">LOGIN IN</h1><div id="errorMsg">${login_msg}</div><p>Username:<input id="username" name="username" type="text"></p><p>Password:<input id="password" name="password" 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">&nbsp;&nbsp;&nbsp;<a href="register.html">没有账号？</a></div></form>
</div></body>
</html>

loginService

@WebServlet("/loginServlet")
public class loginServlet extends HttpServlet {private UserService service = new UserService();@Overrideprotected 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 remenber = request.getParameter("remenber");//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(remenber)){//勾选了，发送cookie对象//1.创建cookie对象Cookie c_username = new Cookie("username",username);Cookie c_password = new Cookie("password",password);//设置cookie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);}//将登录成功后的user对象，储存到Session中HttpSession session = request.getSession();session.setAttribute("user",user);String contextPath = request.getContextPath();response.sendRedirect(contextPath+"/selectAllServlet");}else {//登录失败//存储错误信息到requestrequest.setAttribute("login_msg","用户名或密码错误");//跳转到login.jsprequest.getRequestDispatcher("/login.jsp").forward(request,response);}}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

勾选登录成功后：
在这里插入图片描述

2.4.2 - II 获取cookie

在这里插入图片描述

刷新后：

<%--Created by IntelliJ IDEA.User: 19148Date: 2023/8/4Time: 23:39To change this template use File | Settings | File Templates.
--%>
<%@ 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" id="form"><h1 id="loginMsg">LOGIN IN</h1><div id="errorMsg">${login_msg}</div><p>Username:<input id="username" name="username" value="${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">&nbsp;&nbsp;&nbsp;<a href="register.html">没有账号？</a></div></form>
</div></body>
</html>

在这里插入图片描述

2.4.3 用户注册

在这里插入图片描述

<%--Created by IntelliJ IDEA.User: 19148Date: 2023/8/5Time: 10:47To change this template use File | Settings | File Templates.
--%>
<%@ 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 src="imgs/a.jpg"><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>
</body>
</html>

registerService

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();@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//1.获取用户和密码数据String username = request.getParameter("username");String password = request.getParameter("password");User user = new User();user.setUsername(username);user.setPassword(password);//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request.setAttribute("register_msg","用户已经存在");request.getRequestDispatcher("/register.jsp").forward(request,response);}}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

<%--Created by IntelliJ IDEA.User: 19148Date: 2023/8/4Time: 23:39To change this template use File | Settings | File Templates.
--%>
<%@ 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" 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">&nbsp;&nbsp;&nbsp;<a href="register.jsp">没有账号？</a></div></form>
</div></body>
</html>

成功：
在这里插入图片描述

失败：

2.4.4 验证码

在这里插入图片描述

CheckCodeUtil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("E://JSP-demo1/brand-demo/src/main/webapp/imgs/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* @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);}}}
}

在这里插入图片描述
验证码图片会跟随变化：

<%--Created by IntelliJ IDEA.User: 19148Date: 2023/8/5Time: 10:47To change this template use File | Settings | File Templates.
--%>
<%@ 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();//加个参数避免同上面的路径缓存，但是这个参数在多次点击下必须要永远不一样}
</script>
</body>
</html>

checkCodeServlet

@WebServlet("/checkCodeServlet")
public class checkCodeServlet extends HttpServlet {@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {ServletOutputStream os = response.getOutputStream();String checkCode = CheckCodeUtil.outputVerifyImage(100, 50, os, 4);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

在这里插入图片描述

2.4.4 - I 校验验证码

在这里插入图片描述
registerServlet：

@WebServlet("/registerServlet")
public class registerServlet extends HttpServlet {private UserService service = new UserService();@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//1.获取用户和密码数据String username = request.getParameter("username");String password = request.getParameter("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");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);//比对验证码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;}}else{//注册失败request.setAttribute("register_msg","用户已经存在");request.getRequestDispatcher("/register.jsp").forward(request,response);}}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}