一数据库

CREATE TABLE `user` (
  `id` int(11) DEFAULT NULL,
  `name` varchar(255) DEFAULT NULL,
  `pwd` varchar(255) DEFAULT NULL
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

二 pom文件

<?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>org.cakin</groupId>
    <artifactId>mybatisDemo</artifactId>
    <packaging>pom</packaging>
    <version>1.0-SNAPSHOT</version>
    <modules>
        <module>mybatis-01</module>
    </modules>
    <!--导入依赖-->
    <dependencies>
        <!--mysql驱动包-->
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.46</version>
        </dependency>
        <!--mybatis-->
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.5.2</version>
        </dependency>
        <!--junit-->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>
    </dependencies>
    <!--在build中配置resources，来防止我们资源导出失败的问题-->
    <build>
        <resources>
            <resource>
                <directory>src/main/resources</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
            <!--下面这个一定要加，否则扫描不到 UserMapper.xml 这个文件，会报错-->
            <resource>
                <directory>src/main/java</directory>
                <includes>
                    <include>**/*.properties</include>
                    <include>**/*.xml</include>
                </includes>
                <filtering>true</filtering>
            </resource>
        </resources>
    </build>
</project>

三创建工具类，用来获得sqlSession

package com.cakin.utils;


import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;


import java.io.InputStream;


/**
* @ClassName: Mybatisutil
* @Description: Mybatis工具类
* @Date: 2020/6/12
* @Author: cakin
*/
// sqlSessionFactory-->sqlSession
public class MybatisUtil {
    private static SqlSessionFactory sqlSessionFactory;


    static {
        try {
            // 使用Mybatis第一步：获取sqlSessionFactory对象
            String resource = "mybatis-config.xml";
            InputStream inputStream = Resources.getResourceAsStream(resource);
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }


    // 从sqlSessionFactory获取sqlSession
    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();
    }
}

四 Mybatis核心配置文件配置

<?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.jdbc.Driver"/>
                <!--下面这个写法要牢记-->
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis?useUnicode=true&amp;characterEncoding=utf8&amp;useSSL=true"/>
                <property name="username" value="root"/>
                <property name="password" value="123456"/>
            </dataSource>
        </environment>
    </environments>
    <!--每一个mapper都要在mybatis核心配置文件中配置-->
    <mappers>
        <mapper resource="com/cakin/mapper/UserMapper.xml"></mapper>
    </mappers>
</configuration>

五实体类

package com.cakin.pojo;


/**
* @ClassName: User
* @Description: User实体类
* @Date: 2020/6/12
* @Author: cakin
*/
public class User {
    private int id;
    private String name;
    private String pwd;;


    public User() {
    }


    public User(int id, String name, String pwd) {
        this.id = id;
        this.name = name;
        this.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;
    }


    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", name='" + name + '\'' +
                ", pwd='" + pwd + '\'' +
                '}';
    }
}

六 mapper类

package com.cakin.mapper;


import com.cakin.pojo.User;


import java.util.List;


public interface UserMapper {
    List<User> getUserList();
}

七 mapper的XML配置

<?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">
<!--namespace=绑定一个对应的mappper接口-->
<mapper namespace="com.cakin.mapper.UserMapper">
    <select id="getUserList" resultType="com.cakin.pojo.User">
        select * from user
    </select>
</mapper>

八测试

package com.cakin.mapper;


import com.cakin.pojo.User;
import com.cakin.utils.MybatisUtil;
import org.apache.ibatis.session.SqlSession;
import org.junit.Test;


import java.util.List;


/**
* @ClassName: UserDaoTest
* @Description: 测试类
* @Date: 2020/6/12
* @Author: cakin
*/
public class UserDaoTest {
    @Test
    public void test(){
        // 第一步，获得sqlSession
        SqlSession sqlSession = MybatisUtil.getSqlSession();
        // 执行SQL
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        List<User> userList = userMapper.getUserList();
        for (User user : userList) {
            System.out.println(user);
        }
        // 关闭session
        sqlSession.close();
    }
}

九测试结果

User{id=1, name='cakin', pwd='12345'}
User{id=2, name='cakin24', pwd='123456'}

十官方文档参考

https://mybatis.org/mybatis-3/zh/getting-started.html

来源：oschina

链接：https://my.oschina.net/u/4260642/blog/4309940

标签

MyBatis

MyBatis官方入门实例十步走

一 数据库

二 pom文件

三 创建工具类，用来获得sqlSession

四 Mybatis核心配置文件配置

五 实体类

六 mapper类

七 mapper的XML配置

八 测试

九 测试结果

十 官方文档参考

一数据库

三创建工具类，用来获得sqlSession

五实体类

八测试

九测试结果

十官方文档参考