案例-基于MVC和三层架构实现商品表的增删改查

文章目录

- - [0. 项目介绍](#0. 项目介绍)
  - [1. 环境准备](#1. 环境准备)
  - [2. 查看所有](#2. 查看所有)
  - - [2.1 编写BrandMapper接口](#2.1 编写BrandMapper接口)
    - [2.2 编写服务类，创建BrandService，用于调用该方法](#2.2 编写服务类，创建BrandService，用于调用该方法)
    - [2.5 编写Servlet](#2.5 编写Servlet)
    - [2.4 编写brand.jsp页面](#2.4 编写brand.jsp页面)
    - [2.5 测试](#2.5 测试)
  - 3.添加
  - - [3.1 编写BrandMapper接口添加方法](#3.1 编写BrandMapper接口添加方法)
    - [3.2 编写服务](#3.2 编写服务)
    - [3.3 改写Brand.jsp页面，添加新增按钮，并跳转到新的jsp页面（addBrand页面）](#3.3 改写Brand.jsp页面，添加新增按钮，并跳转到新的jsp页面（addBrand页面）)
    - [3.4 编写Servlet](#3.4 编写Servlet)
    - [3.5 测试](#3.5 测试)
  - 4.修改/回显
  - - [4.1 回显数据](#4.1 回显数据)
    - [4.2 修改数据](#4.2 修改数据)
  - [5. 删除](#5. 删除)

0. 项目介绍

其他项目-用户登录注册页面：https://blog.csdn.net/meini32/article/details/132305323

项目介绍

需求：完成品牌数据的增删改查操作

技术框架说明

三层架构是将我们的项目分成了三个层面，分别是表现层、业务逻辑层、数据访问层。

整个流程是，浏览器发送请求，表现层的Servlet接收请求并调用业务逻辑层的方法进行业务逻辑处理，而业务逻辑层方法调用数据访问层方法进行数据的操作，依次返回到serlvet，然后servlet将数据交由 JSP 进行展示。

数据访问层：Mybatis、mysql

业务逻辑层：JAVA

表现层：JSP、Servlet

实现步骤

1. 环境准备

环境准备

创建新的项目 brand_demo，引入坐标配置pom文件（）

创建三层架构的包结构

数据库表 tb_brand

实体类 Brand

MyBatis 基础环境配置

Mybatis-config.xml

BrandMapper.xml

BrandMapper接口

Mybatis-config.xml

xml 复制代码

<?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.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="123456"/>
            </dataSource>
        </environment>
    </environments>

    <mappers>
        <!--扫描mapper-->
        <package name="com.itheima.mapper"/>
    </mappers>
</configuration>

pom.xml文件配置

xml 复制代码

<?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>8</maven.compiler.source>
        <maven.compiler.target>8</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>5.1.34</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>
        <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>

工具类 SqlsessionFactoryUtils

java 复制代码

package com.itheima.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{
        InputStream inputStream = null;
        try {
            inputStream = Resources.getResourceAsStream("mybatis-config.xml");
        } catch (IOException e) {
            e.printStackTrace();
        }
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
    }

    public static SqlSessionFactory getSqlSessionFactory(){
        return sqlSessionFactory;
    }
}

属性名称对应不上解决方法

在BrandMapper映射文件里，定义映射关系

xml 复制代码

<?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">


<!--
namespace:名称空间
-->

<mapper namespace="com.itheima.mapper.BrandMapper">

<!--    resultMap 标签定义映射关系-->
    <resultMap id="brandRseultMap" type="brand">
        <result column="brand_name" property="brandName"></result>
        <result column="company_name" property="companyName"></result>
    </resultMap>

</mapper>

在接口方法中指定该映射

java 复制代码

public interface BrandMapper {

    //查看所有
    @ResultMap("brandResultMap")
    @Select("select * from tb_brand;")
    List<Brand> selectAll();
}

2. 查看所有

说明：当我们点击 index.html 页面中的查询所有这个超链接时，就能查询到上图右半部分的数据。

2.1 编写BrandMapper接口

java 复制代码

public interface BrandMapper {

    //查看所有
    @Select("select * from tb_brand;")
    List<Brand> selectAll();
}

2.2 编写服务类，创建BrandService，用于调用该方法

java 复制代码

package com.itheima.service;

import com.itheima.mapper.BrandMapper;
import com.itheima.pojo.Brand;
import com.itheima.util.SqlSessionFactoryUtils;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import java.util.List;

public class BrandService {

    SqlSessionFactory sqlSessionFactory =SqlSessionFactoryUtils.getSqlSessionFactory();

    //查所有
    public List<Brand> selectAll(){
        //调用BrandMapper中的selectAll方法

        //获取SqlSession
        SqlSession sqlSession = sqlSessionFactory.openSession();

        //获取Mapper
        BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);

        //调用方法
        List<Brand> brands = brandMapper.selectAll();

        sqlSession.close();
        return brands;

    }
}

2.5 编写Servlet

java 复制代码

package com.itheima.web;

import com.itheima.pojo.Brand;
import com.itheima.service.BrandService;

import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.util.List;

@WebServlet("/selectAllServlet")
public class SelectAllServlet extends HttpServlet {
    //创建这个服务
    private  BrandService service = new BrandService();
    @Override
    protected 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.jsp
        request.getRequestDispatcher("/brand.jsp").forward(request,response);
    }

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        this.doGet(request, response);
    }
}

2.4 编写brand.jsp页面

xml 复制代码

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ page isELIgnored="false" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<!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>${brand.id}</td>
      <td>${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==0}">
        <td>禁止</td>
      </c:if>

      <td><a href="/brand-demo/selectByIdServlet?id=${brand.id}">修改</a> <a href="#">删
        除</a></td>

    </tr>
  </c:forEach>


</table>

</body>
</html>

2.5 测试

3.添加

3.1 编写BrandMapper接口添加方法

java 复制代码

//添加
    @Insert("insert into tb_brand values(null,#{brandName},#{companyName},#{ordered},#{description},#{status})")
    void add(Brand brand);

3.2 编写服务

java 复制代码

public class BrandService {

    SqlSessionFactory sqlSessionFactory =SqlSessionFactoryUtils.getSqlSessionFactory();
    
    //添加数据

    public void add(Brand brand){
        //调用BrandMapper中的selectAll方法

        //获取SqlSession
        SqlSession sqlSession = sqlSessionFactory.openSession();

        //获取Mapper
        BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);

        //调用方法
        brandMapper.add(brand);
        
        //提交事务
        sqlSession.commit();

        sqlSession.close();
        
    }
}

3.3 改写Brand.jsp页面，添加新增按钮，并跳转到新的jsp页面（addBrand页面）

xml 复制代码

<%--
  Created by IntelliJ IDEA.
  User: 11445
  Date: 2023/8/18
  Time: 20:31
  To 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="" 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>

3.4 编写Servlet

在 web 包下创建 AddServlet 的 servlet ，该 servlet 的逻辑如下:

设置处理post请求乱码的字符集

接收客户端提交的数据

将接收到的数据封装到 Brand 对象中

调用 BrandService 的 add() 方法进行添加的业务逻辑处理

跳转到 selectAllServlet 资源重新查询数据

java 复制代码

package com.itheima.web;

import com.itheima.pojo.Brand;
import com.itheima.service.BrandService;

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("/addServlet")
public class AddServlet extends HttpServlet {

    private BrandService service = new BrandService();

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //处理post请求的乱码问题
        req.setCharacterEncoding("utf-8");


        //1. 接收表单提交的数据，封装为一个Brand对象
        String brandName = req.getParameter("brandName");
        String companyName = req.getParameter("companyName");
        String ordered = req.getParameter("ordered");
        String description = req.getParameter("description");
        String status = req.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
        service.add(brand);

        //3. 转发到查询所有Servlet
        req.getRequestDispatcher("/selectAllServlet").forward(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doGet(req,resp);
    }
}

3.5 测试

4.修改/回显

在该修改页面我们可以看到将编辑按钮所在行的数据回显到表单，然后需要修改那个数据在表单中进行修改，然后点击提交的按钮将数据提交到后端，后端再将数据存储到数据库中。

4.1 回显数据

java 复制代码

//编写BrandMapper接口 添加方法
//回显，根据id查询
    @Select("select * from tb_brand where id = #{id}}")
    @ResultMap("brandResultMap")
    Brand selectById(int id);

java 复制代码

//编写服务
import java.util.List;

public class BrandService {

    SqlSessionFactory sqlSessionFactory =SqlSessionFactoryUtils.getSqlSessionFactory();
    
    public Brand selectById(int id){
        //调用BrandMapper中的selectById方法

        //获取SqlSession
        SqlSession sqlSession = sqlSessionFactory.openSession();

        //获取Mapper
        BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);

        //调用方法
        Brand brand = brandMapper.selectById(id);


        sqlSession.close();
        
        return brand;
    }
}

java 复制代码

编写servlet方法
package com.itheima.web;

import com.itheima.pojo.Brand;
import com.itheima.service.BrandService;

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;
import java.util.List;

@WebServlet("/selectByIdServlet")
public class SelectByIdServlet extends HttpServlet {
    //创建这个服务
    private BrandService service = new BrandService();

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //接受id
        String id = req.getParameter("id");

        //1. 调用BrandService完成查询
       Brand brand = service.selectById(Integer.parseInt(id));

        //2. 存入request域中
        req.setAttribute("brand",brand);

        //3. 转发到brand.jsp
        req.getRequestDispatcher("/update.jsp").forward(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}

xml 复制代码

//编写update xml
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
<%@ page isELIgnored="false" %>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>

<!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="/updateServlet" method="post">

  <%--隐藏域，提交id--%>
  <input type="hidden" name="id" value="${brand.id}">

  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="${brand.ordered}"><br>
  描述信息：<textarea rows="5" cols="20" name="description">${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>

修改Brand.jsp的修改连接地址

效果

4.2 修改数据

//修改

@Update("update tb_brand set brand_name = #{brandName},company_name = #{companyName},ordered =\n" +

"#{ordered},description = #{description},status = #{status} where id = #{id}")

void update(Brand brand);

java 复制代码

//    修改
    public void update(Brand brand){
        //调用BrandMapper中的selectById方法

        //获取SqlSession
        SqlSession sqlSession = sqlSessionFactory.openSession();

        //获取Mapper
        BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);

        //调用方法
        brandMapper.update(brand);

        //提交
        sqlSession.commit();

        sqlSession.close();
    }

java 复制代码

@WebServlet("/updateServlet")
public class UpdateServlet extends HttpServlet {
    //创建这个服务
    private BrandService service = new BrandService();
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        //处理post请求的乱码问题
        req.setCharacterEncoding("utf-8");


        //1. 接收表单提交的数据，封装为一个Brand对象
        String id = req.getParameter("id");
        String brandName = req.getParameter("brandName");
        String companyName = req.getParameter("companyName");
        String ordered = req.getParameter("ordered");
        String description = req.getParameter("description");
        String status = req.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
        service.update(brand);

        //3. 转发到查询所有Servlet
        req.getRequestDispatcher("/selectAllServlet").forward(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doGet(req,resp);
    }
}

5. 删除

java 复制代码

   //删除
    @Delete("delete from tb_brand where id = #{id}")
    void deleteById(int id);

java 复制代码

  public void deleteById(int id){
        SqlSession sqlSession = sqlSessionFactory.openSession();
        BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);
        brandMapper.deleteById(id);
        sqlSession.commit();
        sqlSession.close();
    }

java 复制代码

@WebServlet("/deleteByIdServlet")
public class DeleteByIdServlet extends HttpServlet {
    BrandService service = new BrandService();
    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String id = req.getParameter("id");
        service.deleteById(Integer.parseInt(id));
        req.getRequestDispatcher("/selectAllServlet").forward(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        this.doPost(req, resp);
    }
}

案例-基于MVC和三层架构实现商品表的增删改查

文章目录

0. 项目介绍

1. 环境准备

2. 查看所有

2.1 编写BrandMapper接口

2.2 编写服务类，创建BrandService，用于调用该方法

2.5 编写Servlet

2.4 编写brand.jsp页面

2.5 测试

3.添加

3.1 编写BrandMapper接口 添加方法

3.2 编写服务

3.3 改写Brand.jsp页面，添加新增按钮，并跳转到新的jsp页面（addBrand页面）

3.4 编写Servlet

3.5 测试

4.修改/回显

4.1 回显数据

4.2 修改数据

5. 删除

3.1 编写BrandMapper接口添加方法