MyBatis起步搭建

1 步骤

数据库环境
创建Maven项目
导入依赖
编写MyBatis配置文件
编写MyBatis工具类
编写实体类
编写Mapper
测试

2 数据库环境

MySQL 8.0版本

create database mybatis;

use mybatis;

create table `user`(

	`id` int(20) primary key,

    `name` varchar(30) default null,

    `pwd` varchar(30) default null

) engine=InnoDB default charset=utf8;

insert into user(id,name,pwd) values

(1,'张一','111111'),

(2,'张二','222222'),

(3,'张三','333333')

select * from user;

3 创建项目并导入依赖

创建普通的maven项目

导入依赖

<!-- 导入坐标 -->

<dependencies>

    <!-- mysql -->

    <dependency>

        <groupId>mysql</groupId>

        <artifactId>mysql-connector-java</artifactId>

        <version>8.0.11</version>

    </dependency>

    <!-- mybatis -->

    <dependency>

        <groupId>org.mybatis</groupId>

        <artifactId>mybatis</artifactId>

        <version>3.5.5</version>

    </dependency>

    <!-- junit -->

    <dependency>

        <groupId>junit</groupId>

        <artifactId>junit</artifactId>

        <version>4.13.1</version>

    </dependency>

</dependencies>

配置resources，防止资源导出失败

<build>

    <resources>

        <resource>

            <directory>src/main/resources</directory>

            <includes>

                <include>**/*.properties</include>

                <include>**/*.xml</include>

            </includes>

            <filtering>true</filtering>

        </resource>

        <resource>

            <directory>src/main/java</directory>

            <includes>

                <include>**/*.properties</include>

                <include>**/*.xml</include>

            </includes>

            <filtering>true</filtering>

        </resource>

    </resources>

</build>

4 编写MyBatis配置文件

mybatis-config.xml

<?xml version="1.0" encoding="UTF8"?>

<!DOCTYPE configuration

        PUBLIC "-//mybatis.org//DTD Config 3.0//EN"

        "http://mybatis.org/dtd/mybatis-3-config.dtd">

<!-- 核心配置文件 -->

<configuration>

    <!-- 配置环境-->

    <environments default="mysql">

        <environment id="mysql">

            <transactionManager type="JDBC">

            </transactionManager>

            <dataSource type="POOLED">

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

                <property name="url" value="jdbc:mysql://127.0.0.1:3306/mybatis?serverTimezone=UTC"/>

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

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

            </dataSource>

        </environment>

    </environments>

    <!-- 映射配置文件 -->

    <mappers>

        <mapper resource="com/tanyiqu/mapper/UserMapper.xml"/>

    </mappers>

</configuration>

5 编写MyBatis工具类

创建util包并创建MybatisUtil类

MybatisUtil.java

package com.tanyiqu.util;

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;

/**

 * mybatis工具类

 */

public class MybatisUtil {

    private static SqlSessionFactory sqlSessionFactory;

    static {

        try {

            // 获取SqlSessionFactory对象

            String resource = "mybatis-config.xml";

            InputStream inputStream = Resources.getResourceAsStream(resource);

            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        } catch (IOException e) {

            e.printStackTrace();

        }

    }

    public static SqlSession getSqlSession() {

        return sqlSessionFactory.openSession();

    }

}

6 编写实体类

创建pojo包并创建User类

User.java

package com.tanyiqu.pojo;

public class User {

    private int id;

    private String name;

    private String pwd;

    @Override

    public String toString() {

        return "User{" +

                "id=" + id +

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

                ", pwd='" + pwd + '\'' +

                '}';

    }

    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 String getPwd() {

        return pwd;

    }

    public void setPwd(String pwd) {

        this.pwd = pwd;

    }

}

7 编写Mapper

创建mapper包并创建UserMapper接口

UserMapper.java

package com.tanyiqu.mapper;

import com.tanyiqu.pojo.User;

import java.util.List;

public interface UserMapper {

    List<User> getUsers();

}

创建UserMapper配置文件，在UserMapper.java同级目录下创建UserMapper.xml文件

UserMapper.xml

<?xml version="1.0"  encoding="UTF8"?>

<!DOCTYPE mapper

        PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"

        "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<mapper namespace="com.tanyiqu.mapper.UserMapper">

    <select id="getUsers" resultType="com.tanyiqu.pojo.User">

        select * from user

    </select>

</mapper>

8 测试

在test文件夹里面创建测试类

MyTest.java

public class UserMapperTest {

    @Test

    public void getUsers() {

        SqlSession sqlSession = MybatisUtil.getSqlSession();

        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);

        List<User> users = userMapper.getUsers();

        for (User user : users) {

            System.out.println(user);

        }

        sqlSession.close();

    }

}

执行成功！

巴特西