1.创建数据表（库名为：mayikt）
CREATE TABLE `mayikt_user` (
`id` int NOT NULL AUTO_INCREMENT,
`username` varchar(20) DEFAULT NULL,
`userpwd` varchar(20) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=9 DEFAULT CHARSET=utf8mb32.创建maven项目
没下载安装或者不会创建的小伙伴可以看这里：maven的下载安装与配置环境变量！！！（全网最详细）_明天更新的博客-CSDN博客
创建完成后配置pom.xml文件：
<dependencies>
<!-- /org.mybatis/mybatis -->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.13</version>
</dependency>
<!-- com.mysql/mysql-connector-j -->
<dependency>
<groupId>com.mysql</groupId>
<artifactId>mysql-connector-j</artifactId>
<version>8.1.0</version>
</dependency>
</dependencies>3.在main文件夹下的resources文件夹下创建mybatis-config.xml（该配置文件名称是可以改） 存放就是我们数据库相关连接信息
<?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.cj.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://127.0.0.1:3306/mayikt?serverTimezone=GMT%2B8"/>
<property name="username" value="root"/>
<property name="password" value=""/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="mapper/userMapper.xml"/>
</mappers>
</configuration>4.定义mapper ----编写我们mybatis 相关 sql语句 每个表 对应一个mapper
<?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="userMapper">
<select id="getByUsers" resultType="com.entity.UserEntity">
select * from mayikt_user
</select>
</mapper>5.定义java对象--需要注意下 类中的 成员属性与数据库表中字段 映射 默认 类中的 成员属性数据库表中字段名称对应的
/*
* Copyright (c) 2020, 2023, All rights reserved.
*
*/
package com.entity;
/**
* <p>Project: mybatis-dome - UserEntity</p>
* <p>Powered by scl On 2023-09-08 10:18:39</p>
* <p>描述：<p>
*
* @author 孙臣龙 [1846080280@qq.com]
* @version 1.0
* @since 17
*/
public class UserEntity {
private Integer id;
private String username;
private String userpwd;
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public String getUserpwd() {
return userpwd;
}
public void setUserpwd(String userpwd) {
this.userpwd = userpwd;
}
@Override
public String toString() {
return "UserEntity{" +
"id=" + id +
", username='" + username + '\'' +
", userpwd='" + userpwd + '\'' +
'}';
}
}6.测试，使用 mybatis api开始执行该 sql语句即可 得到结果
/*
* Copyright (c) 2020, 2023, All rights reserved.
*
*/
package com.test;
import com.entity.UserEntity;
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;
/**
* <p>Project: mybatis-dome - Test01</p>
* <p>Powered by scl On 2023-09-08 10:29:37</p>
* <p>描述：<p>
*
* @author 孙臣龙 [1846080280@qq.com]
* @version 1.0
* @since 17
*/
public class Test01 {
public static void main(String[] args) throws IOException {
// 1.读取加载mybatis-config.xml
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
// 2.获取到获取到
SqlSession sqlSession = sqlSessionFactory.openSession();
// 3.根据 mapper id=getByUsers 执行该s ql 语句 通过 sql语句得到我们的对象 orm
List<UserEntity> userEntitys = sqlSession.selectList("getByUsers", UserEntity.class);
System.out.println(userEntitys);
sqlSession.close();
}
}
