mybatis源码-工程搭建

项目结构：

引入依赖：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.laoxu</groupId>
    <artifactId>mybatis-executor</artifactId>
    <version>1.0</version>
    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.18</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.7-SNAPSHOT</version>
        </dependency>
        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.6</version>
        </dependency>
    </dependencies>


</project>

创建person表：

创建person数据库交互类：

package com.laoxu.mybatis.modal;


import java.io.Serializable;


public class Person implements Serializable {


    private String id;
    private String name;
    private String sex;
    private String age;
    private String createTime;

    public String getId() {
        return id;
    }

    public void setId(String id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public String getAge() {
        return age;
    }

    public void setAge(String age) {
        this.age = age;
    }

    public String getCreateTime() {
        return createTime;
    }

    public void setCreateTime(String createTime) {
        this.createTime = createTime;
    }
}

创建映射：

package com.laoxu.mybatis.mapper;

import com.laoxu.mybatis.modal.Person;

public interface PersonMapper {

    Person getPersonById(String id);

}

创建person映射xml：

PersonMapper.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="com.laoxu.mybatis.mapper.PersonMapper">
    <resultMap id="BaseResultMap" type="com.laoxu.mybatis.modal.Person">
        <id column="id" jdbcType="VARCHAR" property="id" />
        <result column="name" jdbcType="VARCHAR" property="name" />
        <result column="sex" jdbcType="INTEGER" property="sex" />
        <result column="age" jdbcType="INTEGER" property="age" />
        <result column="create_time" jdbcType="TIMESTAMP" property="createTime" />
    </resultMap>
    <sql id="Base_Column_List">
        id, `name`, sex, age, create_time
    </sql>
    <select id="getPersonById" resultMap="BaseResultMap">
        select * from person where id = #{id}
    </select>



</mapper>

创建mybatis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>
    <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://ip:3306/mybatis?serverTimezone=UTC"/>
                <property name="username" value="username"/>
                <property name="password" value="password"/>
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="mapper/PersonMapper.xml"/>
    </mappers>
</configuration>

environments：指定环境，默认development

dataSource：数据源配置

mappers：指定映射器

测试：

插入几条数据：

package com.laoxu.mybatis.executor;

import com.laoxu.mybatis.modal.Person;
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 com.alibaba.fastjson.JSONObject;

import java.io.IOException;
import java.io.InputStream;

public class start {

    public static void main(String[] args) throws IOException {


        String resource = "mapper/mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        try (SqlSession session = sqlSessionFactory.openSession()) {
            Person person = (Person) session.selectOne("com.laoxu.mybatis.mapper.PersonMapper.getPersonById", "20210420172645864088a2a1ba11eb886d525400146075");
            System.out.println(JSONObject.toJSONString(person));

        }

    }


}

运行后可以查询到一条数据：