package com.itheima;
import com.itheima.entiy.Brand;
import com.itheima.mapper.BrandMapper;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import java.io.IOException;
import java.io.InputStream;
import java.util.List;
//快速入门
public class MytabisApplication {
public static void main(String[] args) throws IOException {
//1.加载核心配置文件，获取SqlSessionFactory 对象
String resource = "mybatis-config.xml"; //定义了配置文件的路径
InputStream inputStream = Resources.getResourceAsStream(resource);//然后通过Resources这个对象提供的静态方法去接收核心配置文件的路径，返回了一个字节输入流，赋给了inputStream
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);//然后SqlSessionFactoryBuilder这个对象的方法去接收inputStream这个流，会返回一个SqlSessionFactory类型的对象，赋给sqlSessionFactory
//到现在，这个"工厂"就建好了,然后就要去获取SqlSession的对象，进行处理
//2.获取SqlSession对象，用它来执行sql语句
SqlSession sqlSession = sqlSessionFactory.openSession();//sqlSessionFactory这个对象的openSession()方法会返回一个SqlSession对象
//3.执行sql语句
//List<User> users = sqlSession.selectList("test.selectAll");//传入名称空间+sql的标识。这个方法会返回一个list类型的对象
//3.1获取UserMapper接口的代理对象
BrandMapper brandMapper = sqlSession.getMapper(BrandMapper.class);//传入UserMapper这个接口名，返回UserMapper接口的代理对象
//全部查询
List<Brand> brands = brandMapper.selectAll();
System.out.println(brands);
//插入
Brand brand = new Brand();
brand.setId(5);
brand.setStatus(1);
brand.setCompanyName("dwa");
brand.setBrandName("daw");
brand.setDescription("dawdawd");
brand.setOrdered(100);
brandMapper.add(brand);
//删除
//修改
//4.释放资源
sqlSession.close();
}
}
package com.itheima.entiy;
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 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 +
'}';
}
}
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"https://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.itheima.mapper.BrandMapper">
<select id="selectAll" resultType="com.itheima.entiy.Brand">
select * from tb_brand;
</select>
<insert id="add">
insert into tb_brand (brand_name,company_name,ordered,description,status)
values (#{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>
</mapper>
打印数据库怎么有的是空的怎么回事？看了半天没看出哪有问题
