1. pom文件添加依赖

    <dependencies><!--MyBatis核心包--><dependency><groupId>org.mybatis</groupId><artifactId>mybatis</artifactId><version>3.5.3</version></dependency><!--mysql驱动包--><dependency><groupId>mysql</groupId><artifactId>mysql-connector-java</artifactId><version>8.0.21</version></dependency><!--junit测试包--><dependency><groupId>junit</groupId><artifactId>junit</artifactId><version>4.12</version></dependency><!--日志包，方便看sql语句--><dependency><groupId>org.slf4j</groupId><artifactId>slf4j-log4j12</artifactId><version>1.6.1</version></dependency></dependencies>

2. 创建核心配置文件SqlMapConfig.xml

<property name="url" value="jdbc:mysql://localhost:3306/mytestdb"/>

报错：

org.apache.ibatis.exceptions.PersistenceException

注意： 在用8.0版本的jdbc链接数据库jar包时，对于url的设置要加上时区，要用分号分割，在xml文件中，分号；要用&表示，代码示例:jdbc:mysql://localhost:3306/XXXXX?useSSL=false&serverTimezone=GMT
引用自：https://blog.csdn.net/qq_25634457/article/details/82786903评论区

<?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="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://localhost:3306/mytestdb?useSSL=false&amp;serverTimezone=GMT"/><property name="username" value="root"/><property name="password" value="root"/></dataSource></environment></environments><mappers><mapper resource="com/zzz/pojo/DeptMapper.xml"/></mappers>
</configuration>

3. 创建实体类

package com.zzz.pojo;public class Dept {//属性名跟mysql表中的列名完全相同private Integer deptno;private String dname;private String loc;public Integer getDeptno() {return deptno;}public String getDname() {return dname;}public String getLoc() {return loc;}public void setDeptno(Integer deptno) {this.deptno = deptno;}public void setDname(String dname) {this.dname = dname;}public void setLoc(String loc) {this.loc = loc;}public Dept() {}public Dept(Integer deptno, String dname, String loc) {this.deptno = deptno;this.dname = dname;this.loc = loc;}}

4. 创建映射配置文件DeptMapper.xml

<?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.zzz.mapper.DeptMapper"><select id="selectAllDept" resultType="com.zzz.pojo.Dept">select * from dept;</select></mapper>

注：正常该文件应该放在resources文件夹下，这里为了方便和实体类放在了同一个文件夹下，要在pom文件中添加如下依赖：

<!--maven默认编译resources下的文件，添加build，里面有的路径下的xml文件都要编译--><build><resources><resource><directory>src/main/java</directory><includes><include>**/*.xml</include></includes><filtering>true</filtering></resource><resource><directory>src/main/resources</directory><includes><include>**/*.xml</include><include>**/*.properties</include></includes></resource></resources></build>

5. junit测试

package com.zzz.test;import com.zzz.pojo.Dept;
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;
import java.sql.SQLOutput;
import java.util.List;public class MyBatisTest {@Testpublic void test1() throws IOException {// 加载配置文件InputStream resource = Resources.getResourceAsStream("SqlMapConfig.xml");SqlSessionFactoryBuilder  builder = new SqlSessionFactoryBuilder();SqlSessionFactory factory = builder.build(resource);SqlSession session = factory.openSession();List<Dept> list = session.selectList("selectAllDept");for(Dept dept:list){System.out.println(dept.getDeptno() + ";" + dept.getDname() + ";" + dept.getLoc());}session.close();}
}

数据库表：

测试结果输出：

10;accounting;new york
20;research;dallas
30;oprations;boston
40;sales;chicago