案例-基于MVC和三層架構實現商品表的增刪改查

文章目錄

- - 0. 項目介紹
  - 1. 環境準備
  - 2. 查看所有
  - - 2.1 編寫BrandMapper接口
    - 2.2 編寫服務類，創建BrandService，用于調用該方法
    - 2.5 編寫Servlet
    - 2.4 編寫brand.jsp頁面
    - 2.5 測試
  - 3.添加
  - - 3.1 編寫BrandMapper接口添加方法
    - 3.2 編寫服務
    - 3.3 改寫Brand.jsp頁面，添加新增按鈕，并跳轉到新的jsp頁面（addBrand頁面）
    - 3.4 編寫Servlet
    - 3.5 測試

0. 項目介紹

其他項目-用戶登錄注冊頁面：https://blog.csdn.net/meini32/article/details/132305323

項目介紹
需求：完成品牌數據的增刪改查操作
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技術框架說明

三層架構是將我們的項目分成了三個層面，分別是表現層、業務邏輯層、數據訪問層。
整個流程是，瀏覽器發送請求，表現層的Servlet接收請求并調用業務邏輯層的方法進行業務邏輯處理，而業務邏輯層方法調用數據訪問層方法進行數據的操作，依次返回到serlvet，然后servlet將數據交由 JSP 進行展示。

數據訪問層：Mybatis、mysql
業務邏輯層：JAVA
表現層：JSP、Servlet

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實現步驟

1. 環境準備

環境準備

創建新的項目 brand_demo，引入坐標配置pom文件（）

創建三層架構的包結構

數據庫表 tb_brand

實體類 Brand

MyBatis 基礎環境配置

Mybatis-config.xml

BrandMapper.xml

BrandMapper接口

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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><!--起別名--><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><!--掃描mapper--><package name="com.itheima.mapper"/></mappers>
</configuration>

pom.xml文件配置

<?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>

工具類 SqlsessionFactoryUtils

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;}
}

屬性名稱對應不上解決方法
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在BrandMapper映射文件里，定義映射關系

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"><!--
namespace:名稱空間
--><mapper namespace="com.itheima.mapper.BrandMapper"><!--    resultMap 標簽定義映射關系--><resultMap id="brandRseultMap" type="brand"><result column="brand_name" property="brandName"></result><result column="company_name" property="companyName"></result></resultMap></mapper>

在接口方法中指定該映射

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

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2. 查看所有

說明：當我們點擊 index.html 頁面中的查詢所有這個超鏈接時，就能查詢到上圖右半部分的數據。
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2.1 編寫BrandMapper接口

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

2.2 編寫服務類，創建BrandService，用于調用該方法

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(){//調用BrandMapper中的selectAll方法//獲取SqlSessionSqlSession sqlSession = sqlSessionFactory.openSession();//獲取MapperBrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);//調用方法List<Brand> brands = brandMapper.selectAll();sqlSession.close();return brands;}
}

2.5 編寫Servlet

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 {//創建這個服務private  BrandService service = new BrandService();@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//1. 調用BrandService完成查詢List<Brand> brands = service.selectAll();//2. 存入request域中request.setAttribute("brands",brands);//3. 轉發到brand.jsprequest.getRequestDispatcher("/brand.jsp").forward(request,response);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request, response);}
}

2.4 編寫brand.jsp頁面

<%@ 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>序號</th><th>品牌名稱</th><th>企業名稱</th><th>排序</th><th>品牌介紹</th><th>狀態</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>啟用</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="#">刪除</a></td></tr></c:forEach></table></body>
</html>

2.5 測試

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3.添加

3.1 編寫BrandMapper接口添加方法

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

3.2 編寫服務

public class BrandService {SqlSessionFactory sqlSessionFactory =SqlSessionFactoryUtils.getSqlSessionFactory();//添加數據public void add(Brand brand){//調用BrandMapper中的selectAll方法//獲取SqlSessionSqlSession sqlSession = sqlSessionFactory.openSession();//獲取MapperBrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);//調用方法brandMapper.add(brand);//提交事務sqlSession.commit();sqlSession.close();}
}

3.3 改寫Brand.jsp頁面，添加新增按鈕，并跳轉到新的jsp頁面（addBrand頁面）

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<%--Created by IntelliJ IDEA.User: 11445Date: 2023/8/18Time: 20:31To 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">品牌名稱：<input name="brandName"><br>企業名稱：<input name="companyName"><br>排序：<input name="ordered"><br>描述信息：<textarea rows="5" cols="20" name="description"></textarea><br>狀態：<input type="radio" name="status" value="0">禁用<input type="radio" name="status" value="1">啟用<br><input type="submit" value="提交">
</form>
</body>
</html>

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3.4 編寫Servlet

在 web 包下創建 AddServlet 的 servlet ，該 servlet 的邏輯如下:

設置處理post請求亂碼的字符集
接收客戶端提交的數據
將接收到的數據封裝到 Brand 對象中
調用 BrandService 的 add() 方法進行添加的業務邏輯處理
跳轉到 selectAllServlet 資源重新查詢數據

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();@Overrideprotected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {//處理post請求的亂碼問題req.setCharacterEncoding("utf-8");//1. 接收表單提交的數據，封裝為一個Brand對象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");//封裝為一個Brand對象Brand brand = new Brand();brand.setBrandName(brandName);brand.setCompanyName(companyName);brand.setOrdered(Integer.parseInt(ordered));brand.setDescription(description);brand.setStatus(Integer.parseInt(status));//2. 調用service 完成添加service.add(brand);//3. 轉發到查詢所有Servletreq.getRequestDispatcher("/selectAllServlet").forward(req,resp);}@Overrideprotected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {this.doGet(req,resp);}
}