用了大概一天半的时间又重新学了一边mybatis框架，下面是感悟和代码并且有目录截图等
感悟
- 感觉第二笔效果还是比第一遍抢多了
- 学习到了一个新工具，mybatisx(黑色的小鸟吖)
- 此处省略很多哈哈哈
步入正题哈哈哈，刚刚看了下笔记居然没有修改 
这里我把增删改查分开写了哈,等会我会注明代码分别放到什么文件里面，这样方便你们测试运行学习等
代码目录截图
项目是MybatisDemo03这个项目，01，02是别的东西
配置文件
需要手动配置下property标签里面的东西，账号密码，数据库东西我会放在下面
<?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> <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://127.0.0.1:3306/mybatis"/> <property name="username" value="***"/> <property name="password" value="**"/> </dataSource> </environment> </environments> <mappers> <mapper resource="com/xiaonan/mapper/BrandMapper.xml"/> </mappers> </configuration>
实体类
复制进去，切记换包名，idea好像可以直接就换好了
package com.xiaonan.pojo; /** * 品牌 * * alt + 鼠标左键：整列编辑 * * 在实体类中，基本数据类型建议使用其对应的包装类型 */ 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 + '}'; } }
空的mapper配置文件
<?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.xiaonan.mapper.BrandMapper">
</mapper>空的mapper接口文件
package com.xiaonan.mapper;
public interface BrandMapper {
}
空的test测试类
package com.xiaonan.test;
public class MybatisTest {
}以上文件准备好，开始代码部分
查询是最多的一个
查询
mapper接口文档
//直接遍历集合
List<Brand> selectAll();mapper接口配置文档
<!--
数据库的字段和实体类的属性名称不一样时
*起别名:对不一样的列明起别名
*缺点每次都要定义一次别名
*定义sql片段
*resultMap
1.定义<resultMap>标签
2.在select标签中,使用resultMap属性替换resulttype属性
-->
<resultMap id="brandsesultMap" type="com.xiaonan.pojo.Brand">
<!--
id:唯一标识
type:映射的类型,支持别名
column:数据库表中字段的名字
property:实体类中的名字,这里也就是别名
result:完成字段的映射
-->
<result column="brand_name" property="brandName"/>
<result column="company_name" property="companyName"/>
</resultMap>
<select id="selectAll" resultMap="brandsesultMap">
select * from tb_brand;
</select>
<!-- sql片段-->
<!--
<sql id="brand_column">
id,brand_name as brandName, company_name as companyName, ordered, description, status
</sql>
<select id="selectAll" resultType="com.xiaonan.pojo.Brand">
select
<include refid="brand_column"/>
from tb_brand;
</select>
-->
<!--起别名 -->
<!--
<select id="selectAll" resultType="com.xiaonan.pojo.Brand">
select id,brand_name as brandName, company_name as companyName, ordered, description, status from tb_brand;
</select>
-->
<!-- 数据库字段和实体类属性名称不一样
<select id="selectAll" resultType="com.xiaonan.pojo.Brand">
select * from tb_brand;
</select>
-->测试类test
@Test
public void selectAll() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession=sqlSessionFactory.openSession();
BrandMapper brandMapper=sqlSession.getMapper(BrandMapper.class);
List<Brand> list=brandMapper.selectAll();
System.out.println(list);
sqlSession.close();
}根据id查询
mapper接口
Brand selecyByid(int id);mapper配置文档
<select id="selecyByid" resultMap="brandsesultMap">
select * from tb_brand where id=#{id};
</select>测试类
@Test
public void selectById() throws IOException {
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession=sqlSessionFactory.openSession();
BrandMapper brandMapper=sqlSession.getMapper(BrandMapper.class);
Brand brand=brandMapper.selecyByid(1);
System.out.println(brand);
sqlSession.close();
}条件查询
散装查询，对象查询，map集合查询
mapper接口文件
//List<Brand> selectByCondition(@Param("status") int status,@Param("companyName") String companyName,@Param("brandName") String brandName);
//List<Brand> selectByCondition(Brand brand);
List<Brand> selectByCondition(Map map);mapper配置文件
<!-- 条件查询 -->
<!--
<select id="selectByCondition" resultMap="brandsesultMap">
select *
from tb_brand
where status=#{status}
and company_name like #{companyName}
and brand_name like #{brandName}
</select>
-->
<!-- 动态sql -->
<!--
*if:条件判断
*test:逻辑表达式
*问题:
*恒等式:过度作用
*where标签
-->
<!--
<select id="selectByCondition" resultMap="brandsesultMap">
select *
from tb_brand
where 1=1
<if test="status !=null">
and status=#{status}
</if>
<if test="companyName !='' and companyName !=null">
and company_name like #{companyName}
</if>
<if test="brandName !=null and brandName!='' ">
and brand_name like #{brandName}
</if>
</select>
-->
<select id="selectByCondition" resultMap="brandsesultMap">
select *
from tb_brand
<where>
<if test="status !=null">
and status=#{status}
</if>
<if test="companyName !='' and companyName !=null">
and company_name like #{companyName}
</if>
<if test="brandName !=null and brandName!='' ">
and brand_name like #{brandName}
</if>
</where>
</select>测试类
@Test
public void selectByCondition() throws IOException {
//散装
int status =1;
String companyName="华为";
String brnadName="华为";
companyName="%"+companyName+"%";
brnadName="%"+brnadName+"%";
//对象
//Brand brand=new Brand();
//brand.setStatus(1);
//brand.setCompanyName("%华为%");
//brand.setBrandName("%华为%");
//map集合
Map map=new HashMap();
map.put("status",status);
map.put("companyName",companyName);
map.put("brandName",brnadName);
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession=sqlSessionFactory.openSession();
BrandMapper brandMapper=sqlSession.getMapper(BrandMapper.class);
//List<Brand> list=brandMapper.selectByCondition(status,companyName,brnadName);
//List<Brand> list=brandMapper.selectByCondition(1,"%华为%","%华为");
//对象
//List<Brand> list=brandMapper.selectByCondition(brand);
//集合
List<Brand> list=brandMapper.selectByCondition(map);
System.out.println(list);
sqlSession.close();
}添加
mapper接口文件
void add(Brand brand);mapper配置文件
<insert id="add" useGeneratedKeys="true" keyProperty="id">
insert into tb_brand (brand_name,company_name,ordered,description,status)
values (#{brandName},#{companyName},#{ordered},#{description},#{status});
</insert>测试类
@Test
public void add() throws IOException {
//对象
Brand brand=new Brand();
brand.setStatus(1);
brand.setCompanyName("测试");
brand.setBrandName("测试");
brand.setDescription("测试1111");
brand.setOrdered(100);
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession=sqlSessionFactory.openSession(true);
BrandMapper brandMapper=sqlSession.getMapper(BrandMapper.class);
brandMapper.add(brand);
System.out.println("id===="+brand.getId());
sqlSession.commit();
sqlSession.close();
}删除
批量删除(介绍还是用配置文件)
mapper接口文件
void deleteByIds(@Param("ids")int [] ides);mapper配置文件
<!--
mybatis会将数组参数，封装为一个map集合
*默认，array=数组
*使用@Param注解改变map集合默认key的名称
-->
<delete id="deleteByIds">
delete from tb_brand where id
in(
<foreach collection="ids" item="id" separator=",">
#{id}
</foreach>
);
</delete>测试类
@Test
public void deleteByIds() throws IOException {
int [] ids={4,5};
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession=sqlSessionFactory.openSession(true);
BrandMapper brandMapper=sqlSession.getMapper(BrandMapper.class);
brandMapper.deleteByIds(ids);
sqlSession.commit();
sqlSession.close();
}重点！！！！！
在mybatis中不仅可以配置文件开发但是还可以注解开发，这里我介绍介绍不过不提倡注解开发，因为sql长了有点力不从心的感觉
注解开发
删除，根据id删除
mapper接口文件，这次用不到mapper配置文件了
@Delete("delete from tb_brand where id=#{id}")
void deleteByid(int id);测试类
//注解开发
@Test
public void deleteById() throws IOException {
int id=6;
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
SqlSession sqlSession=sqlSessionFactory.openSession(true);
BrandMapper brandMapper=sqlSession.getMapper(BrandMapper.class);
brandMapper.deleteByid(id);
sqlSession.commit();
sqlSession.close();
}注解开发，就上面俩文件，mapper接口文件还要一个测试类接口，没有mapper配置文件
增，删如果运行ok，但是数据库表中没有变化，那是没有提交数据，需要这样操作，在测试类里面这样修改下即可
//两种方法
//1:直接在这里就填写参数为true
//SqlSession sqlSession=sqlSessionFactory.openSession(true);
//2:这里不填写参数的话 那就在sql执行之后
// SqlSession sqlSession=sqlSessionFactory.openSession();
//sqlSession.commit();数据库，直接复制到工具里面运行即可
-- 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;这是全部的东西，处理改，我忘记写了哈哈哈哈，不过大同小异，感觉不错的麻烦点个赞哈哈哈 
文章全部是本人原创，请勿转发，谢谢配合，版权所有-南香香-你会喜欢我吗
真认真，好样的