1.创建工程

2.引入相关的依赖 pom.xml

    org.mybatismybatis3.4.6junitjunit4.12testmysqlmysql-connector-java8.0.18runtimelog4jlog4j1.2.17

3.准备数据库

这里使用的是数据库是mybatis

use mybatis;
create table users(uid int primary key auto_increment,uname varchar(20) not null,uage int not null
);
insert into users(uid,uname,uage) values(null,'张三',20),(null,'李四',18);

4.创建mybatis的核心配置文件所使用的db.properties文件

jdbc.driver=com.mysql.cj.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/mybatis?serverTimezone=UTC&characterEncoding=utf8&useUnicode=true&useSSL=false
jdbc.username=root
jdbc.password=root

5.创建项目结构

5.1 创建com.example.pojo包存放实体类User

实体类User的内容如下

package com.example.pojo;/*** ClassName: User* Package: com.example.pojo* Description:** @Create 2023/3/16 7:52* @Version 1.0*/
public class User {private int uid;private String uname;private int uage;public int getUid() {return uid;}public void setUid(int uid) {this.uid = uid;}public String getUname() {return uname;}public void setUname(String uname) {this.uname = uname;}public int getUage() {return uage;}public void setUage(int uage) {this.uage = uage;}@Overridepublic String toString() {return "User{" +"uid=" + uid +", uname='" + uname + '\'' +", uage=" + uage +'}';}
}

5.2 创建com.example.mapper包存mapper接口

UserMapper接口如下

package com.example.mapper;/*** ClassName: UserMapper* Package: com.example.mapper* Description:** @Create 2023/3/16 7:55* @Version 1.0*/
public interface UserMapper {
}

6.创建Mybatis核心配置文件mybatis-config.xml

mybatis-config.xml内容如下

7.创建Mybatis映射文件UserMapper.xml

7.1创建目录结构

7.2 UserMapper.xml内容如下

8.创建log4j.xml的配置文件

内容如下：

9.创建测试文件TestMybatis.java

9.第一个测试案例

根据User的id查找User

9.1 com.example.mapper.UserMapper.java接口文件中添加方法

public interface UserMapper {/*** 根据用户id查找用户*/public User findUserById(int id);
}

9.2 UserMapper.xml映射文件添加sql语句

select * from users where uid = #{id}

9.3 com.example.test.TestMybatis.java中添加测试方法

package com.example.test;import com.example.mapper.UserMapper;
import com.example.pojo.User;
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 org.junit.Test;import java.io.IOException;
import java.io.InputStream;/*** ClassName: TestMyBatis* Package: com.example.test* Description:** @Create 2023/3/16 8:07* @Version 1.0*/
public class TestMyBatis {@Testpublic void testFindUserById() throws IOException {//1.获取核心配置类InputStream is = Resources.getResourceAsStream("mybatis-config.xml");//2.创建SqlSessionFacotrySqlSessionFactory sqlSessionFacotry = new SqlSessionFactoryBuilder().build(is);//3.获取SqLSession对象SqlSession session = sqlSessionFacotry.openSession();//4.执行sql语句UserMapper mapper = session.getMapper(UserMapper.class);User user = mapper.findUserById(1);System.out.println("user = " + user);//5。释放资源session.close();}
}

10.运行结果如下