1、导入相关的jar包：mysql.jar、mybatis3.jar

2、src下,编写mysql.properties文件

driver=com.mysql.jdbc.Driver
url=jdbc:mysql://localhost:3306/cs_db
username=root
password=123

3、src下编写mybatis-config.xml总配置文件

XML申明:
<!DOCTYPE configuration
PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">ML样例:

<?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>

                <!-- 驱动配置文件 -->
                <properties resource="mysql.properties"/>

                <!-- 别名映射 -->
                <typeAliases>   
                    <!-- 自动扫描包下的Bean -->
                    <package name="me.mxzf.domain"/>
                    <typeAlias type="me.mxzf.domain.Student" alias="Student"/>
                </typeAliases>

                <!-- 环境 -->
                <environments default="development">
                    <environment id="development">
                        <transactionManager type="JDBC" />
                        <dataSource type="POOLED">
                            <property name="driver" value="${driver}" />
                            <property name="url" value="${url}" />
                            <property name="username" value="${username}" />
                            <property name="password" value="${password}" />
                        </dataSource>
                    </environment>
                </environments>
                <!-- Bean映射Sql文件 -->
                <mappers>
                    <mapper resource="me/mxzf/mapping/StudentMapper.xml" />
                </mappers>
            </configuration>

4、编写对应的类的sql映射文件

XML申明:
<!DOCTYPE mapper
                PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
                "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

        XML样例:

        <?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="me.mxzf.mapping.StudentMapper">
            <select id="selectStudent" resultType="Student">
                select * from student where sid = #{sid}
            </select>
        </mapper>

6、通过namespace+id的方式去访问对应的sql语句

//从XML中构建SqlSessionFactory

        //如果配置文件在src目录下，resource = "mybatis-config.xml";
        //否则resource = 具体的包路径 + 文件名

        String resource = "org/mybatis/example/mybatis-config.xml";
        InputStream inputStream = Resources.getResourceAsStream(resource);
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        //在总配置文件中mappers里注册所有的sql映射文件
        <mapper resource="me/mxzf/mapping/StudentMapper.xml"/>
        ...

        //从SqlSessionFactory中获取SqlSession
        SqlSession session = sessionFactory.openSession();
        try {
                //me.mxzf.mapping.StudentMapper 命名空间
                //insertStudent 在此命名空间下有个id为insertStudent的mapper

            session.insert("me.mxzf.mapping.StudentMapper.insertStudent",
                student);
            session.commit();
        } catch (Exception e) {
            session.rollback();
        } finally {
            session.close();
        }

        在总配置文件中配置Bean别名(properties?,settings?,typeAliases?,typeHandlers?,objectFactory?,objectWrapperFactory?,plugins?,environments?,databaseIdProvider?,mappers?)
        <typeAliases>   
            <!-- 自动扫描包下的Bean -->
            <package name="me.mxzf.domain"/>
            <typeAlias type="me.mxzf.domain.Student" alias="Student"/>
        </typeAliases>

7、通过接口和java注解的方式

//接口
    public interface StudentDAO {
            @Select("select * from student where sid=#{sid}")
         public Student selectStudentById(int sid);
     }

Mybatis注解学习 – xxxMapper is not known to the MapperRegistry

Mybatis注解一定要注册自己写的接口类，不然就会老报开头提到的这个错误

1、factory.getConfiguration().addMapper(UserInfoMapper.class);//动态注册

2、 //静态注册

3、演示CRUD操作

1、UserMapper接口文件

        public interface UserMapper {  
             @Insert("insert into users(name, age) values(#{name}, #{age})")  
             public int add(Users user);  

                @Delete("delete from users where id = #{id}")  
                public int deleteById(int id);  

                @Update("update users set name = #{name}, age = #{age} where id = #{id}")  
                public int update(Users user);  

                @Select("select * from users where id = #{id}")  
                public Users getUserById(int id);  

                @Select("select * from users")  
                public List<Users> getAllUsers();  
        }

        2、在总配置文件mappers中注册UserMapper这个接口

        <mapper class="com.bird.mybatis.bean.UserMapper"/>

        3、使用这个类

        SqlSession openSession = factory.openSession();  
        UserMapper mapper = openSession.getMapper(UserMapper.class);
            //动态注入到接口中  
            mapper.add(new Users(-1,"娃娃",99));
            //提交修改  
            openSession.commit();  
            openSession.close();