🍁环境

• JDK1.8
• Mysql5.7
• maven 3.6.3
• IDEA

🍁第一个MyBatis程序

步骤：
搭建环境–>导入Mybatis–>编写代码–>测试。

🔥搭建环境

• 搭建数据库
• 新建项目
• 新建一个普通maven项目
• 导入maven依赖

🔥搭建数据库

1.创建一个数据库名为mybatis的tb_user表

2.向表中添加数据

🔥导入maven依赖

pom:

• maven依赖代码置于 pom.xml 文件中：

<dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.6</version>
        </dependency>

• 导入MySQL驱动的依赖

<dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.47</version>
        </dependency>

-单元测试依赖

<dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

🔥编写mybatis-config.xml的核心配置文件

mybatis-config.xml:

<?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 core file-->
<configuration>

    <environments default="development">
        <environment id="development">
            <transactionManager type="JDBC"/>
            <dataSource type="POOLED">
                <property name="driver" value="com.mysql.jdbc.Driver"/>
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useSSL=false&amp;useUnicode=true&amp;characterEncoding=UTF-8"/>
                <property name="username" value="root"/>
                <property name="password" value="root"/>
            </dataSource>
        </environment>
    </environments>
    <!--加载sql映射文件-->
    <mappers>
        <mapper resource="com.jkj.UserMapper.xml"/>
    </mappers>
</configuration>

🔥 编写Mapper.xml的配置文件

userMapper.xml:

<?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="test">
    <select id="selectAll" resultType="com.jkj.pojo.User">
    select * from tb_user;
  </select>
</mapper>

🔥 编写User实体类代码：

package com.jkj.pojo;

public class User {
    private Integer id;
    private String username;
    private String password;
    private String gender;
    private String addr;

    public User() {
    }

    public User(Integer id, String username, String password, String gender, String addr) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.gender = gender;
        this.addr = addr;
    }

    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 getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public String getAddr() {
        return addr;
    }

    public void setAddr(String addr) {
        this.addr = addr;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", gender='" + gender + '\'' +
                ", addr='" + addr + '\'' +
                '}';
    }
}

🔥编写mybatisTest测试类

MyBatisUtils：

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

public class MybatisTest {
    public static void main(String[] args) throws IOException {
        //1.加载MyBatis的核心配置文件获取sqlSessionFactory
        String resource = "mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        //2.获取sqlSession,执行sql
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //3.执行sql
        List<User> users = sqlSession.selectList("test.selectAll");
        System.out.println(users);
        //4.释放资源
        sqlSession.close();
    }
}

🔥运行截图：