1. 环境搭建

1.1 数据初始化

//创建库
CREATE DATABASE tj_mybatis_learning;
//创建表
CREATE TABLE tbl_department (
  id varchar(32) NOT NULL,
  deptName varchar(32) NOT NULL,
  phone varchar(18) DEFAULT NULL,
  PRIMARY KEY (id)
) ENGINE=InnoDB DEFAULT CHARSET=utf8mb4;
//初始化数据
INSERT INTO tbl_department(id, deptName, phone) VALUES ('18ec781fbefd727923b0d35740b177ab', '开发部', '110');
INSERT INTO tbl_department(id, deptName, phone) VALUES ('53e3803ebbf4f97968e0253e5ad4cc83', '测试产品部', '111');
INSERT INTO tbl_department(id, deptName, phone) VALUES ('ee0e342201004c1721e69a99ac0dc0df', '运维部', '112');

1.2 Maven工程创建

pom.xml依赖

    <dependencies>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.5</version>
        </dependency>

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

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.16.18</version>
            <scope>provided</scope>
        </dependency>

        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>
    </dependencies>
	
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                </configuration>
            </plugin>
        </plugins>
    </build>

日志文件log4j.properties

log4j.rootCategory=debug, CONSOLE

# Set the enterprise logger category to FATAL and its only appender to CONSOLE.
log4j.logger.org.apache.axis.enterprise=FATAL, CONSOLE

# CONSOLE is set to be a ConsoleAppender using a PatternLayout.
log4j.appender.CONSOLE=org.apache.log4j.ConsoleAppender
log4j.appender.CONSOLE.Encoding=UTF-8
log4j.appender.CONSOLE.layout=org.apache.log4j.PatternLayout
log4j.appender.CONSOLE.layout.ConversionPattern=%d{ISO8601} %-6r [%15.15t] %-5p %30.30c %x - %m \n

mybatis全局的配置文件 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>
    <settings>
        <setting name="logImpl" value="LOG4J"/>
    </settings>
    <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/tj_mybatis_learning?characterEncoding=utf-8"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="mapper/department.xml"/>
    </mappers>
</configuration>

部门mapper.xml的编写

<?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="departmentMapper">

    <select id="findAll" resultType="com.tongjun.mybatis.entity.Department">
        select * from tbl_department
    </select>
</mapper>

实体类编写

package com.tongjun.mybatis.entity;

import lombok.Data;

import java.io.Serializable;

/**
 * @author tj
 * @date 2022/8/25 10:26
 * @Version 1.0
 */
@Data
public class Department implements Serializable {

    private String id;

    private String deptName;

    private String phone;

}

测试程序编写

package com.tongjun.mybatis.app;

import com.tongjun.mybatis.entity.Department;
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.InputStream;
import java.util.List;

/**
 * @author tj
 * @date 2022/8/25 10:28
 * @Version 1.0
 */
public class ApplicationTest {
    public static void main(String[] args) throws Exception{
        //拿到mybatis配置文件的流
        InputStream resourceAsStream = Resources.getResourceAsStream("mybatis-config.xml");
        //创建sqlSession工厂
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        //通过工厂拿到sqlSession对象
        SqlSession sqlSession = sqlSessionFactory.openSession();
        //通过sqlSession调用mapper
        List<Department> list = sqlSession.selectList("departmentMapper.findAll");
        list.forEach(System.out::println);
    }
}

执行程序，查看结果，控制台输出

Department(id=18ec781fbefd727923b0d35740b177ab, deptName=开发部, phone=110)
Department(id=53e3803ebbf4f97968e0253e5ad4cc83, deptName=测试产品部, phone=111)
Department(id=ee0e342201004c1721e69a99ac0dc0df, deptName=运维部, phone=112)

如果可以输出结果，说明基础代码已经成功了