目录
1.环境准备
环境准备工作,我们分以下步骤实现:
-
创建新的模块 brand_demo,引入坐标
-
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
-
Mybatis-config.xml
-
BrandMapper.xml
-
BrandMapper接口
-
2.创建工程
创建新的模块 brand_demo,引入坐标。我们只要分析出要用到哪儿些技术,那么需要哪儿些坐标也就明确了
-
需要操作数据库。mysql的驱动包
-
要使用mybatis框架。mybaits的依赖包
-
web项目需要用到servlet和jsp。servlet和jsp的依赖包
-
需要使用 jstl 进行数据展示。jstl的依赖包
pom.xml
内容如下:
<?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">
<parent>
<artifactId>test</artifactId>
<groupId>org.example</groupId>
<version>1.0-SNAPSHOT</version>
</parent>
<modelVersion>4.0.0</modelVersion>
<artifactId>brand-demo</artifactId>
<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,JSP标准标签库-->
<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>
3.创建包
创建不同的包结构,用来存储不同的类。包结构如下
4.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);
5.创建实体类
在 pojo
包下创建名为 Brand
的类。
package com.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 +
'}';
}
}
6.准备mybatis环境
定义核心配置文件 Mybatis-config.xml
,并将该文件放置在 resources
下
<?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.pojo"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
//数据库地址
<property name="url" value="jdbc:mysql://localhost:13306/db1"/>
<property name="username" value="root"/>
<property name="password" value="1234"/>
</dataSource>
</environment>
</environments>
<mappers>
<!--扫描mapper-->
<package name="com.mapper"/>
</mappers>
</configuration>
在 resources
下创建放置映射配置文件的目录结构 com/mapper
(注意:这个包名创建时只能使用"/",不能使用".",xml和原文件包的结构应该一样)
,并在该目录下创建映射配置文件 BrandMapper.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">
<mapper namespace="com.mapper.BrandMapper">
<resultMap id="brandResultMap" type="brand">
<result column="brand_name" property="brandName"></result>
<result column="company_name" property="companyName"></result>
</resultMap>
<insert id="add">
insert into tb_brand values(null,#{brandName},#{companyName},#{ordered},#{description},#{status});
</insert>
<update id="update">
update tb_brand set brand_name=#{brandName},company_name=#{companyName},ordered=#{ordered},
description=#{description},status=#{status} where id=#{id};
</update>
<delete id="delete">
delete from tb_brand where id=#{id};
</delete>
<select id="selectAll" resultMap="brandResultMap">
select * from tb_brand;
</select>
<select id="selectByIdBrand" resultMap="brandResultMap">
select * from tb_brand where id=#{id};
</select>
</mapper>
7.查询所有
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。
对于上述的功能,点击 查询所有
超链接是需要先请后端的 servlet
,由 servlet
跳转到对应的页面进行数据的动态展示。而整个流程如下图:
7.1编写BrandMapper
在 mapper
包下创建创建 BrandMapper
接口,在接口中定义 selectAll()
方法
List<Brand> selectAll();
7.2编写工具类
在 com
包下创建 utils
包,并在该包下创建名为 SqlSessionFactoryUtils
工具类
package com.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 {
//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;
}
}
7.3编写BrandService
在 service
包下创建 BrandService
类
package com.service;
import com.mapper.BrandMapper;
import com.pojo.Brand;
import com.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();
// 查询所有
public List<Brand> selectAll(){
SqlSession sqlSession = sqlSessionFactory.openSession();
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
List<Brand> brands = mapper.selectAll();
sqlSession.close();
return brands;
}
// 添加数据
public void add(Brand brand)
{
SqlSession sqlSession = sqlSessionFactory.openSession();
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
mapper.add(brand);
// 增删改需要提交事务才能正常进行,查询不需要
sqlSession.commit();
sqlSession.close();
}
//按照id查询
public Brand selectById(int id){
SqlSession sqlSession = sqlSessionFactory.openSession();
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
Brand brand = mapper.selectByIdBrand(id);
sqlSession.close();
return brand;
}
//修改
public void Update(Brand brand){
SqlSession sqlSession = sqlSessionFactory.openSession();
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
mapper.update(brand);
sqlSession.commit();
sqlSession.close();
}
//删除
public void Delete(Brand brand){
SqlSession sqlSession = sqlSessionFactory.openSession();
BrandMapper mapper = sqlSession.getMapper(BrandMapper.class);
mapper.delete(brand);
sqlSession.commit();
sqlSession.close();
}
}
7.4编写Servlet
在 web
包下创建名为 SelectAllServlet
的 servlet
,该 servlet
的逻辑如下:
-
调用
BrandService
的selectAll()
方法进行业务逻辑处理,并接收返回的结果 -
将上一步返回的结果存储到
request
域对象中 -
跳转到
brand.jsp
页面进行数据的展示
具体的代码如下
package com.web;
import com.pojo.Brand;
import com.service.BrandService;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
import java.util.List;
@WebServlet(name = "SelectAllServlet", value = "/SelectAllServlet")
public class SelectAllServlet extends HttpServlet {
private BrandService brandService = new BrandService();
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
BrandService brandService = new BrandService();
List<Brand> brands = brandService.selectAll();
request.setAttribute("brands",brands);
request.getRequestDispatcher("/brand.jsp").forward(request,response);
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
this.doGet(request, response);
}
}
7.5编写brand.jsp页面
在brand.jsp
页面在表格中使用 JSTL
和 EL表达式
从request域对象中获取名为 brands
的集合数据并展示出来。页面内容如下:
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%@ page isELIgnored="false" %>
<html>
<head>
<title>显示页面</title>
</head>
<body>
<input type="button" value="新增" id="add"><br>
<table border="1px">
<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="${brands}" var="brand">
<tr align="center"bgcolor="#ffc0cb">
<td>${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!=1}">
<td>禁止</td>
</c:if>
<td><a href="/brand-demo/selectByIdServlet?id=${brand.id}">修改</a> <a href="/brand-demo/DeleteServlet?id=${brand.id}">删除</a></td>
</tr>
</c:forEach>
</table>
<script>
document.getElementById("add").onclick=function (){
location.href="/brand-demo/AddBrand.jsp";
}
</script>
</body>
</html>
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