MyBatis学习（一）基本配置与使用

1、前期准备

文件具体架构图

1、配置conf.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">

                <!-- 配置数据库信息 -->

                <property name="driver" value="com.mysql.cj.jdbc.Driver"/>

                <property name="url" value="jdbc:mysql://localhost:3306/xiao?serverTimezone=GMT%2B8"/>

                <property name="username" value="root"/>

                <property name="password" value="123456"/>

            </dataSource>

        </environment>

    </environments>

    <mappers>

        <!--   加载映射文件     -->

        <mapper resource="com/feng/entity/personMapper.xml"/>

    </mappers>

</configuration>

2、创建对应的表和实体类

package com.feng.entity;

public class Person {

    private int id;

    private String name;

    private int age;

    public Person(int id, String name, int age) {

        this.id = id;

        this.name = name;

        this.age = age;

    }

    public Person() {

    }

    public int getId() {

        return id;

    }

    public void setId(int id) {

        this.id = id;

    }

    public String getName() {

        return name;

    }

    public void setName(String name) {

        this.name = name;

    }

    public int getAge() {

        return age;

    }

    public void setAge(int age) {

        this.age = age;

    }

    @Override

    public String toString() {

        return "Person{" +

                "id=" + id +

                ", name='" + name + '\'' +

                ", age=" + age +

                '}';

    }

}

对应mysql中的表如图所示：

3、配置对应的映射文件xxxMapper.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.feng.entity.personMapper">

    <select id="queryPersonById" resultType="com.feng.entity.Person" parameterType="int">

         select * from person where id = #{id}

    </select>

</mapper>

4、创建对应的测试类

package com.feng.entity;

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.Reader;

public class TestMyBatis {

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

        // 1、加载MyBatis配置文件、为了访问数据库

        Reader reader = Resources.getResourceAsReader("com/feng/conf.xml");

        // 2、sqlSessionFactory -- connection

        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);

        SqlSession sqlSession = sqlSessionFactory.openSession();

        // 3、执行查询、需要所在映射文件的namespace + id 值

        String statement = "com.feng.entity.personMapper.queryPersonById";

        Person person = sqlSession.selectOne(statement, 1);

        System.out.println(person);

        // 4、关闭连接

        sqlSession.close();

    }

}

巴特西

MyBatis学习（一）基本配置与使用

MyBatis学习（一）基本配置与使用

1、前期准备

1、配置conf.xml

2、创建对应的表和实体类

3、配置对应的映射文件xxxMapper.xml

4、创建对应的测试类

2、运行结果

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