一、环境搭建

1、导入MyBatis的坐标和其他相关坐标

<?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.example</groupId>
    <artifactId>MyBatis</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>5.1.32</version>
        </dependency>
        <dependency>
            <groupId>org.mybatis</groupId>
            <artifactId>mybatis</artifactId>
            <version>3.4.5</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
            <scope>test</scope>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.12</version>
        </dependency>
        <dependency>
            <groupId>com.github.pagehelper</groupId>
            <artifactId>pagehelper</artifactId>
            <version>3.7.5</version>
        </dependency>
        <dependency>
            <groupId>com.github.jsqlparser</groupId>
            <artifactId>jsqlparser</artifactId>
            <version>1.0</version>
        </dependency>

    </dependencies>

</project>

2、创建数据表

3、编写实体类

public class User {
    private int id;
    private String username;
    private String password;
    private Date birthday;
    //以及相应的get、set、toString方法
}

4、编写Mapper映射文件（xml开发需要编写）

<?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="dao.UserMapper">
<mapper namespace="userMapper">    
	<select id="findAll" resultType="domain.User">        
		select * from User    
	</select>
</mapper>

5、编写配置文件（可选择将配置文件内容直接写入核心文件）

jdbc.driver=com.mysql.jdbc.Driver
jdbc.url=jdbc:mysql://localhost:3306/test
jdbc.username=root
jdbc.password=998516

6、编写MyBatis核心文件

<?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>

    <!--    通过properties标签加载外部properties文件-->
    <properties resource="jdbc.properties"></properties>
    
    <!--    注意：typeAliases标签的位置需要处于properties标签、settings标签后面，其它标签的前面！！！！-->
    <!--    自定义别名-->
    <typeAliases>
        <!--       mybatis已经把基本数据类型的别名封装好了-->
        <typeAlias type="domain.User" alias="user"></typeAlias>
        <typeAlias type="domain.Order" alias="order"></typeAlias>
        <typeAlias type="domain.Role" alias="role"></typeAlias>
    </typeAliases>
    
    <!--    注册类型处理器-->
    <typeHandlers>
        <typeHandler handler="handler.DateTypeHandler"></typeHandler>
    </typeHandlers>
    
    <!--    配置分页插件-->
    <plugins>
        <plugin interceptor="com.github.pagehelper.PageHelper">
            <property name="dialect" value="mysql"></property>
        </plugin>
    </plugins>

    <!--数据源环境-->
    <environments default="developement"> <!--default用于选择默认environment -->
        <environment id="developement">
            <transactionManager type="JDBC"></transactionManager>
            <dataSource type="POOLED">
                <property name="driver" value="${jdbc.driver}"/>
                <property name="url" value="${jdbc.url}"/>
                <property name="username" value="${jdbc.username}"/>
                <property name="password" value="${jdbc.password}"/>
            </dataSource>
        </environment>
    </environments>


    <!--    加载映射文件  （xml开发） -->
    <mappers>
        <mapper resource="mapper/UserMapper.xml"></mapper>
        <mapper resource="mapper/OrderMapper.xml"></mapper>
    </mappers>


     <!--    加载映射关系  （注解开发）-->
    <mappers>
        <!--        指定接口所在的包-->
        <package name="dao"/>
    </mappers>
    

</configuration>

二、使用

1、定义接口（xml开发）

1、定义接口（注解开发）?

     //保存
    @Insert("insert into user values (#{id},#{username},#{password},#{birthday})")
    public void save(User user);
    // 删除
    @Delete("delete from user where id=#{id}")
    public void delete(int id);
    // 修改
    @Update("update user set username=#{username} , password=#{password}  where id=#{id}")
    public void update(User user);
    //查询所有
    @Select("select * from user")
    public List<User> findAll() throws IOException;
    //根据id查询
    @Select("select * from user where id=#{id}")
    public User findById(int id);

2、service层调用?

 InputStream resourceAsStream = Resources.getResourceAsStream("sqlMapConfig.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(resourceAsStream);
        SqlSession sqlSession = sqlSessionFactory.openSession(true);
        UserMapper mapper = sqlSession.getMapper(UserMapper.class);

        List<User> userList = mapper.findAllOrder();
        for (User user : userList) {
            System.out.println(user);
        }

        sqlSession.close();