一、MyBatis开发步骤

MyBatis开发七步走，开看看是哪七步

1. 创建实体类
2. 实体别名
3. 建表
4. 创建DAO接口
5. 编写Mapper文件
6. 注册Mapper文件
7. 调用API

开始之前，先把环境搭建好，首先 pom 文件中引入相关依赖

<dependencies><!--Spring 工厂核心--><dependency><groupId>org.springframework</groupId><artifactId>spring-context</artifactId><version>5.1.10.RELEASE</version></dependency><!--效率插件 lombok--><dependency><groupId>org.projectlombok</groupId><artifactId>lombok</artifactId><version>1.18.12</version></dependency><!--连接mysql驱动包--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>5.1.48</version></dependency><!--mybatis框架包--><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.4.6</version></dependency>
</dependencies>

在 resources 目录下创建 mybatis 的配置文件 mybatis-config.xml，根据自己的情况进行配置即可

<?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><environments default="mysql"><environment id="mysql"><transactionManager type="JDBC"/><dataSource type="POOLED"><property name="driver" value="com.mysql.jdbc.Driver"/><property name="url" value="jdbc:mysql://localhost:3306/zhou?useSSL=false"/><property name="username" value="root"/><property name="password" value="root"/></dataSource></environment></environments><mappers><mapper resource="org/mybatis/example/BlogMapper.xml"/></mappers>
</configuration>

包结构如下：

在这里插入图片描述

1.1、创建实体类

创建 User 实体类

@Data
@AllArgsConstructor
@NoArgsConstructor
public class User implements Serializable {private Integer id;private String name;private String pwd1;
}

1.2、实体别名

在 mybatis-config.xml 中的 configuration 配置中配置别名

<typeAliases><!--方便mapper文件编写，不用写全限定名了，使用别名即可--><typeAlias alias="user" type="com.liu.mybatis.User"/>
</typeAliases>

1.3、建表

在 mysql 数据库中创建与实体类 User 映射的表

-- 创建数据库，名为zhou
mysql> create database zhou;
Query OK, 1 row affected (0.00 sec)
-- 使用zhou数据库
mysql> use zhou
Database changed
-- 创建t_users表
mysql> create table t_users(-> id int primary key auto_increment,-> name varchar(12),-> pwd1 varchar(12));
Query OK, 0 rows affected (0.05 sec)
-- 查看所有表
mysql> show tables;
+----------------+
| Tables_in_zhou |
+----------------+
| t_users        |
+----------------+
1 row in set (0.00 sec)
-- 查看表结构
mysql> desc t_users;
+-------+-------------+------+-----+---------+----------------+
| Field | Type        | Null | Key | Default | Extra          |
+-------+-------------+------+-----+---------+----------------+
| id    | int(11)     | NO   | PRI | NULL    | auto_increment |
| name  | varchar(12) | YES  |     | NULL    |                |
| pwd1  | varchar(12) | YES  |     | NULL    |                |
+-------+-------------+------+-----+---------+----------------+
3 rows in set (0.00 sec)

好的，确认无误

1.4、创建DAO接口

package com.liu.mybatis;public interface UserDAO {void save(User user);
}

1.5、编写Mapper文件

<?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.liu.mybatis.UserDAO"><insert id="save" parameterType="user">insert into t_users (name, pwd1)values (#{name}, #{pwd1});</insert></mapper>

1.6、注册Mapper文件

在 mybatis 配置文件中注册 mapper 文件

<mappers><mapper resource="UserMapper.xml"/>
</mappers>

二、测试

public class TestMybatis {public static void main(String[] args) throws IOException {InputStream inputStream = Resources.getResourceAsStream("mybatis-config.xml");SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);SqlSession sqlSession = sqlSessionFactory.openSession();UserDAO mapper = sqlSession.getMapper(UserDAO.class);User user = new User();user.setName("周棋洛");user.setPwd1("123123917");mapper.save(user);// 提交事务sqlSession.commit();}
}

查询数据库：

mysql> select * from t_users;
+----+-----------+-----------+
| id | name      | pwd1      |
+----+-----------+-----------+
|  1 | 周棋洛    | 123123917 |
+----+-----------+-----------+
1 row in set (0.00 sec)