基于三层架构实现简单的web界面的增删改查
案例：完成品牌数据的增删改操作
准备环境
１.创建新的模块ｂｒａｎｄ－ｄｅｍｏ，引入坐标
<dependencies>
<!--mybatis-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.5</version>
</dependency>
<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>
<!--tomcat 插件-->
<plugin>
<groupId>org.apache.tomcat.maven</groupId>
<artifactId>tomcat7-maven-plugin</artifactId>
<version>2.2</version>
</plugin>
</plugins>
</build>
<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<maven.compiler.source>9</maven.compiler.source>
<maven.compiler.target>9</maven.compiler.target>
</properties>
</project>２.创建三层架构的包结构、
３.创建表
-- 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;４.ｂｒａｎｄ实体类
添加到ｐｏｊｏ包中
package com.aiit.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;
}
@Override
public String toString() {
return "Brand{" +
"id=" + id +
", brandName='" + brandName + ''' +
", companyName='" + companyName + ''' +
", ordered=" + ordered +
", description='" + description + ''' +
", status=" + status +
'}';
}
}
５.Ｍｙｂｉｔｓ基础环境
Ｍｙｂｉｔｓ－ｃｏｎｆｉｇ．ｘｍｌ
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<!--起别名-->
<typeAliases>
<package name="com.aiit.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:///db_1?useSSL=false"/>
<property name="username" value="root"/>
<property name="password" value="20020630"/>
</dataSource>
</environment>
</environments>
<mappers>
<!--扫描mapper-->
<package name="com.aiit.mapper"/>
</mappers>
</configuration>ＢｒａｎｄｆＭａｐｐｅｒ．ｘｍｌ
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<!--映射文件-->
<mapper namespace="com.aiit.mapper.BrandMapper">
</mapper>ＢｒａｎｄＭａｐｐｅｒ接口
package com.aiit.mapper;
public interface BrandMapper {
}
具体实现：
一、查询所有
1.创建一个index.html文件
<body>
<a href="http://localhost:8080/1/selectAllServlet">查询所有</a>
</body>2.完成数据访问层的设计
写一个BrandMapper接口
//查询所有
@Select("select * from tb_brand")
@ResultMap("brandResultMap")
List<Brand> selectAll();在BrandMapper.xml中添加
<?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.aiit.mapper.BrandMapper">
<resultMap id="brandResultMap" type="com.aiit.pojo.Brand">
<result column="brand_name" property="brandName"></result>
<result column="company_name" property="companyName"></result>
</resultMap>
</mapper>在util包下创建一个工具类SqlSessionFactoryUtils
用来减少代码的冗余
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;
}
}
3.完成业务逻辑层的设计
在Service包下创建BrandService
public class BrandService {
//调用BrandMapper中的selectAll()
SqlSessionFactory factory= SqlSessionFactoryUtils.getSqlSessionFactory();
public List<Brand> selectAll(){
//获取sqlSession
SqlSession sqlSession = factory.openSession();
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
//调用方法
List<Brand> brands = mapper.selectAll();
sqlSession.close();
return brands;
}
}
4.表现层的设计
在web包下创建selectAllServlet
@WebServlet("/selectAllServlet")
public class selectAllServlet extends HttpServlet {
BrandService brandService = new BrandService();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.调用BrandService完成查询
List<Brand> brands = brandService.selectAll();
//2,存入request域中
request.setAttribute("brands",brands);
//3.转发
request.getRequestDispatcher("/brand.jsp").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}创建一个brand.jsp文件在webapp包下
<%@ page contentType="text/html;charset=UTF-8" language="java" isELIgnored="false"%>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
<title>Title</title>
</head>
<body>
</tr>
<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="${brands}" var="brand" varStatus="status">
<tr align="center">
<td>${status.index}</td>
<td>${brand.brandName}</td>
<td>${brand.companyName}</td>
<td>${brand.ordered}</td>
<td>${brand.description}</td>
<td>${brand.status}</td>
<td><a href="#">修改</a> <a href="#">删除</a></td>
</tr>
</c:forEach>
</table>
</body>
</html>
运行结果：
二、添加
1.准备一个添加页面
addBrand.jsp
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2022/7/9
Time: 15:32
To change this template use File | Settings | File Templates.
--%>
<%@ 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>添加品牌</title>
</head>
<body>
<h3>添加品牌</h3>
<form action="http://localhost:8080/1/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>2.在BrandMapper接口中定义一个添加方法
//添加
@Insert("insert into tb_brand values(null,#{brandName},#{companyName},#{ordered},#{description},#{status})")
void add(Brand brand);3.在BrandService中调用BrandMapper中的add()
//添加
public void add(Brand brand){
SqlSession sqlSession = factory.openSession();
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
mapper.add(brand);
//提交事务
sqlSession.commit();
sqlSession.close();
}4.新建一个Servlet命名为selectAllServlet
@WebServlet("/selectAllServlet")
public class selectAllServlet extends HttpServlet {
BrandService brandService = new BrandService();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.调用BrandService完成查询
List<Brand> brands = brandService.selectAll();
//2,存入request域中
request.setAttribute("brands",brands);
//3.转发
request.getRequestDispatcher("/brand.jsp").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
5.在brand中
当点击新增按钮时跳转到addBrand.jsp页面
使用js实现
设置按钮的id
写JS
运行结果：
点击新增
填入信息后点击提交
三、修改
3.1数据回显
1.在BrandMapper接口中定义一个通过id查询的方法
//根据id查询
@Select("select * from tb_brand where id=#{id}")
@ResultMap("brandResultMap")
Brand selectById(int id);2.在BrandService中调用BrandMapper中的selectById()
//根据id查询
public Brand selectById(int id){
SqlSession sqlSession = factory.openSession();
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
//调用方法
Brand brand = mapper.selectById(id);
sqlSession.close();
return brand;
}3.获取点击的id
在brand.jsp中修改，修改按钮的herf 增加一个id=${brand.id}
4.新建一个Servlet命名为selectByIdServlet()
@WebServlet("/selectByIdServlet")
public class selectByIdServlet extends HttpServlet {
private BrandService service=new BrandService();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//1.接受id
String id = request.getParameter("id");
//2.调用service查询
Brand brand = service.selectById(Integer.parseInt(id));
//3.存储到requst中
request.setAttribute("brand",brand);
//4.转发到update.jsp中
request.getRequestDispatcher("/update.jsp").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
5.准备一个页面为update.jsp
<%--
Created by IntelliJ IDEA.
User: Administrator
Date: 2022/7/9
Time: 15:32
To 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="http://localhost:8080/1/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="${brand.ordered}"><br>
描述信息：<textarea rows="5" cols="20" name="description" >${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>效果展示：
点击修改
跳转到update.jsp页面
3.2修改
1.修改update.jsp表单的提交路径
2.在BrandMapper接口中写一个update的sql
//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);3.在BrandService中调用BrandMapper中的update()
//修改
public void update(Brand brand){
SqlSession sqlSession = factory.openSession();
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
mapper.update(brand);
//提交事务
sqlSession.commit();
sqlSession.close();
}4.新建一个Servlet命名为updateServlet()
@WebServlet("/updateServlet")
public class updateServlet extends HttpServlet {
private BrandService service=new BrandService();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置乱码问题
request.setCharacterEncoding("UTF-8");
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));
//调用service完成修改
service.update(brand);
//转发到查询所有的servlet
request.getRequestDispatcher("/selectAllServlet").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request,response);
}
}效果展示：
点击修改按钮
修改排序为1
提交
四、删除
1，修改brand.jsp
修改删除的href，加上获取id
2.在mapper中写sql
//删除
@Delete("delete from tb_brand where id=#{id}")
void delete(int id);3. 在BrandService中调用BrandMapper中的delete()
//删除
public void delete(int id){
SqlSession sqlSession = factory.openSession();
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
mapper.delete(id);
sqlSession.commit();
sqlSession.close();
}4.新建一个Servlet命名为deleteServlet()
@WebServlet("/deleteServlet")
public class deleteServlet extends HttpServlet {
private BrandService service=new BrandService();
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//设置乱码问题
request.setCharacterEncoding("UTF-8");
String id = request.getParameter("id");
//封装对象
//调用service完成修改
service.delete(Integer.parseInt(id));
//转发到查询所有的servlet
request.getRequestDispatcher("/selectAllServlet").forward(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request,response);
}
}
效果展示:
点击删除后
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