JavaWeb小项目（二）- 完成品牌数据的增删改查（JSP/MVC/三层架构综合应用）

文章目录

JavaWeb小项目（二）- 完成品牌数据的增删改查（JSP/MVC/三层架构综合应用）
- 环境搭建
- 查询所有
- 添加数据
- 修改数据
- - 回显数据
  - 修改数据
- 删除数据（额外添加的功能）

涉及技术栈：Java，MyBatis，Servlet，JSP
需要自行导入的包链接：提取码：6666

环境搭建

创建新的模块 brand_demo，并在 pom.xml 文件引入坐标

<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>5.1.46</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>

在 com.itheima 包下创建三层架构的包结构，并将创建（若现成的则导入）数据库表 tb_brand

在 com.itheima.pojo 包下创建实体类 Brand

/*** 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 +'}';}
}

准备 MyBatis 基础环境
在 com.itheima.mapper 创建 BrandMapper

public interface BrandMapper {}

在 resources 文件夹下添加 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://localhost:3306/db1?serverTimezone=Asia/Shanghai&amp;useUnicode=true&amp;characterEncoding=utf-8&amp;zeroDateTimeBehavior=convertToNull&amp;useSSL=false&amp;allowPublicKeyRetrieval=true"/><property name="username" value="root"/><property name="password" value="XXXX"/></dataSource></environment></environments><mappers><!--扫描mapper--><package name="com.itheima.mapper"/></mappers>
</configuration>

在 resources 文件夹下创建 com.itheima.mapper 包，并在该包下创建 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"><!-- 实现数据库驼峰命名法映射 --><resultMap id="brandResultMap" type="brand"><result column="brand_name" property="brandName"></result><result column="company_name" property="companyName"></result></resultMap>
</mapper>

查询所有

实现 Dao 层，通过 select * from tb_brand 实现查询表中的所有内容

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

在实现 Service 层之前将 SqlSessionFactory 类导入到 com.itheima.util 包下

public 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;}
}

实现 Service 层，创建 BrandService 类，实现查询所有的逻辑功能 （基本步骤：建立sql会话，通过sql会话获取mapper对象，最后调用存储在一个变量后返回，注意查询完之后一定要关闭会话）；

/*** 查询所有* @return*/
public List<Brand> selectAll(){//调用BrandMapper.selectAll()SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();//1.获取SqlSessionSqlSession sqlSession = factory.openSession();//2.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//3.调用方法List<Brand> brands = mapper.selectAll();sqlSession.close();return brands;
}

实现 web 层之写好 index.html 页面

<!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>

实现 web 层之实现 SelectAllServlet 类实现页面交互

@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);}
}

实现 web 层之在 webapp 包下实现 brand.jsp 页面

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ 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="${brands}" var="brand"><tr align="center"><td>${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>禁用</td></c:if><td><a href="#">修改</a> <a href="#">删除</a></td></tr></c:forEach></table></body>
</html>

实验效果

添加数据

实现 Dao 层，通过 insert into tb_brand values(null,brand_name,company_name,ordered,description,status) 实现添加数据

public interface BrandMapper {/*** 添加数据* @param brand*/@Insert("insert into tb_brand values(null,#{brandName},#{companyName},#{ordered},#{description},#{status})")void add(Brand brand);
}

实现 Service 层，在 BrandService 类，实现查询所有的逻辑功能 （基本步骤：建立sql会话，通过sql会话获取mapper对象，最后调用并commit，注意查询完之后一定要关闭会话）；

/*** 添加数据* @param brand*/
public void add(Brand brand){//调用BrandMapper.selectAll()SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();//1.获取SqlSessionSqlSession sqlSession = factory.openSession();//2.获取brandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//3.调用方法mapper.add(brand);sqlSession.commit();sqlSession.close();
}

实现 web 层之在 brand.jsp 的头部添加添加 “按钮”
```
<input type="button" value="新增" id="add"><br>
```

实现 web 层之在 brand.jsp 的下面实现添加按钮的 js 脚本

<script>document.getElementById("add").onclick = function (){location.href = "/brand-demo/addBrand.jsp";}
</script>

实现 web 层之写好 addBrand.jsp 页面

<%@ 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>

实现 web 层之实现 AddServlet 类实现页面交互

@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请求的编码处理问题request.setCharacterEncoding("utf-8");//1.接收表单提交的数据，封装为一个Brand对象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");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Servletrequest.getRequestDispatcher("selectAllServlet").forward(request,response);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request,response);}
}

实验结果

修改数据

回显数据

实现 Dao 层，通过 select * from tb_brand where id=#{id} 实现添加数据

public interface BrandMapper {/*** 根据id查询* @param id* @return*/@Select("select * from tb_brand where id=#{id}")@ResultMap("brandResultMap")Brand selectById(int id);
}

实现 Service 层，创建 BrandService 类，实现根据id查询逻辑功能 （基本步骤：建立sql会话，通过sql会话获取mapper对象，最后调用存储在一个变量后返回，注意查询完之后一定要关闭会话）；

/*** 根据id查询* @param id* @return*/
public Brand selectById(int id){//调用BrandMapper.selectById(id)SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();//1.获取SqlSessionSqlSession sqlSession = factory.openSession();//2.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//3.调用方法Brand brand = mapper.selectById(id);sqlSession.close();return brand;
}

修改数据

实现 Dao 层，通过 update tb_brand set brand_name=#{brandName},company_name=#{companyName},ordered=#{ordered},description=#{description},status=#{status} where id=#{id} 实现修改数据

@Update("update tb_brand set brand_name=#{brandName},company_name=#{companyName},ordered=#{ordered},description=#{description},status=#{status} where id=#{id}")
@ResultMap("brandResultMap")
void update(Brand brand);

实现 Service 层，创建 BrandService 类，调用修改数据功能 （基本步骤：建立sql会话，通过sql会话获取mapper对象，注意查询完之后一定要关闭会话）；

/*** 修改数据* @param brand*/
public void update(Brand brand){//调用BrandMapper.update(brand)SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();//1. 获取SqlSessionSqlSession sqlSession = factory.openSession();//2.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//3.调用方法mapper.update(brand);sqlSession.commit();sqlSession.close();
}

实现 web 层之在 brand.jsp 页面把修改链接添加链接地址

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

实现 web 层之在 selectById.jsp 页面回显数据，注意回显的数据回传回id，需要把id隐藏起来，这是不需要展现给用户来看的；

<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ 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/updateServlet" method="post"><input name="id" type="hidden" value="${brand.id}"><br>品牌名称：<input name="brandName" value="${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><input type="submit" value="提交">
</form>
</body>
</html>

实现 web 层之实现 UpdateServlet 类实现页面交互

@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请求的编码处理问题request.setCharacterEncoding("utf-8");//1.接收表单提交的数据，封装为一个Brand对象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");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，完成修改service.update(brand);//3.转发到SelectAllServletrequest.getRequestDispatcher("selectAllServlet").forward(request,response);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request,response);}
}

删除数据（额外添加的功能）

实现 Dao 层，通过 delete from tb_brand where id=#{id} 实现删除数据

/*** 根据id删除数据* @param id*/
@Delete("delete from tb_brand where id=#{id}")
@ResultMap("brandResultMap")
void deleteById(int id);

实现 Service 层，创建 BrandService 类，调用删除数据功能 （基本步骤：建立sql会话，通过sql会话获取mapper对象，注意查询完之后一定要关闭会话）；

/*** 根据id删除数据* @param id*/
public void delete(int id){//调用BrandMapper.delete(id)SqlSessionFactory factory = SqlSessionFactoryUtils.getSqlSessionFactory();//1.获取SqlSessionSqlSession sqlSession = factory.openSession();//2.获取BrandMapperBrandMapper mapper = sqlSession.getMapper(BrandMapper.class);//3.调用方法mapper.deleteById(id);sqlSession.commit();sqlSession.close();
}

实现 web 层之在 brand.jsp 页面把删除链接添加链接地址

<a href="/brand-demo/deleteByIdServlet?id=${brand.id}">删除</a>

实现 web 层之实现 DeleteByIdServlet 类实现页面交互

@WebServlet("/deleteByIdServlet")
public class DeleteByIdServlet extends HttpServlet {private BrandService service = new BrandService();@Overrideprotected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {//1.接收需要删除数据的idString id = request.getParameter("id");//2.调用Serviceservice.delete(Integer.parseInt(id));//3.转发至SelectAllServletrequest.getRequestDispatcher("selectAllServlet").forward(request,response);}@Overrideprotected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {this.doGet(request,response);}
}