一、搭建环境及工具准备

1.java 开发环境：JDK1.8 及以上

2.java 开发工具：eclipse

3.数据库服务器：MySQL

4数据库管理工具：navcat

二、搭建详细步骤

1.创建工程并添加Jar包（mybatis jar包下载地址：https://github.com/mybatis/mybatis-3/release，数据库jar包 MySQL :: Download Connector/J）

2.添加MyBatis核心配置文件

新建一个和src类型的resource文件用于存放MyBatis核心配置文件

?需修改成自己的数据库信息 url、username、password

<?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://localhost:3306/mybatis" />
			<property name="username" value="root" />
			<property name="password" value="123456" />
		</dataSource>
	</environment>
</environments> 
<mappers>
   <mapper resource="UserMapper.xml" />
</mappers>
</configuration>

3.创建实体类

这里数据库表的属性需要与实体类的属性一致！！！

package user;

public class User {
private int age;
private String name;
private String passwordString;
public int getAge() {
	return age;
}
public void setAge(int age) {
	this.age = age;
}
public String getName() {
	return name;
}
public void setName(String name) {
	this.name = name;
}
public String getPasswordString() {
	return passwordString;
}
public void setPasswordString(String passwordString) {
	this.passwordString = passwordString;
}
}

4创建SQL映射文件

id属性：表示该SQL语句的唯一标识符

resultType属性：填写全类名，表示SQL语句返回值类型，此处通过SQL语句查询数据，将数据直接映射到User实体类上

<?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="/">
        <!-- SQL映射写在这里 -->
        <select id="findAllUser" resultType="domain.User">
		select * from user
</select>

</mapper>

5.创建Junit，代码测试，输出结果

?创建TestUser类

package test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

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.*;
import domain.User;
public class UserTest {
@Test
public void findUser() throws IOException {
	//1.加载mybatis核心配置文件
	InputStream inputStream = Resources.getResourceAsStream("mybatis_config.xml");
	//2.获取SqlSessionFactory对象
	SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
	//3.得到执行sql的对象SqlSession 
	SqlSession sqlSession = sqlSessionFactory.openSession();
	//4.执行sql语句
	List<User> list = sqlSession.selectList("findAllUser");
	//5.处理结果
	for (User user: list) {
	System.out.println("用户名："+user.getName()+"，密码："+user.getPassword()+"年纪："+user.getAge());
	}
	//6.关闭数据库会话
	sqlSession.close();
}
	

}