架包和日志的配置文件不一一列举了
一.核心配置文件
<?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>

<properties resource="datainfo.properties"></properties>

<!-- 
typeAliases用来给类起别名的，简化全类名的编写 
typeAliases中可以有多个typeAlias元素，每一个就是针对一个类定义的别名
type：要设定别名的类的全类名     alias：别名
mybatis内置的别名
Integer    Long    Double   List   Map   Set
int   long 

package元素中name属性扫描实体属性所在的包，别名默认为实体类的的名
-->
<typeAliases>
<!-- <typeAlias type="mybaentity.User" alias="User"/> -->
<!-- <package name=""/>是扫描哪个包下面的所有接口 -->
<package name="mybaentity"/>
</typeAliases>


<!-- default与id的名称相同，根据id的名称找到数据库 -->
<environments default="mybati">
    <environment id="mybati">
        <!--
         处理事物的类型 
         事务管理：
         jdbc：以传统的jdbc方式来提交回滚事物，设置了事物，自动提交就会关闭
         MANAGED:以第三方框架的形式来管理事物(spring,Tomcat)
        -->
        <transactionManager type="jdbc"></transactionManager>
        <!--
         数据库连接池类型
         数据库连接池：
         POOLED：使用连接池
         UNPOOLED:不使用连接池
         JNDI：
         -->
        <dataSource type="POOLED">
            <!-- 链接数据库的流程 -->
            <property name="driver" value="${DRIVER}" />
            <property name="url" value="${DBURL}" />
            <property name="username" value="${USERNAME}" />
            <property name="password" value="${USERPWD}" />
        </dataSource>
    </environment>
</environments>

<mappers>
    <!-- 映射找到对应的mapper的核心管理文件，注意只能用斜杠 -->
    <!-- <mapper resource="mybaentity/mapper/User.xml"></mapper> -->
    <!-- 映射到整个包来加载  用扫描包xml必须与对应接口同名同包-->
    <package name="mybaentity.mapper"/>
</mappers>

</configuration>

二 sql配置文件
<?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="mybaentity.mapper.UserMapper">

<select id="getSelectId" parameterType="int" resultType="User">
select * from user where userid = #{userid}
</select>
<select id="selectAll" resultType="User">
select * from user
</select>

</mapper>

三.链接数据库的文件
DRIVER=com.mysql.jdbc.Driver
DBURL=jdbc:mysql://localhost:3306/demo06?useUnicode=true&characterEncoding=utf8

DBNAME=ORCL

USERNAME=root
USERPWD=940906

四.如何利用Mybatis进行数据交互
//利用mybatis的API根数据库进行交互
//加载核心配置文件，参数值是核心配置文件相对于src的路径
Reader reader = Resources.getResourceAsReader("SqlMapConfig.xml");
//构建连接池
SqlSessionFactory sFactory = new SqlSessionFactoryBuilder().build(reader);
//获取链接对象
SqlSession session = sFactory.openSession();
//调用mapper中的接口 mapper也就是原来的DAO
UserMapper uMapper = session.getMapper(UserMapper.class);
//调用方法
User user = uMapper.getSelectId(1);
System.out.println();
List<User> list = uMapper.selectAll();
for (User user2 : list) {
System.out.println(user2.getPhone());
}
System.out.println(user.getPossword());

五.一对一


<mapper namespace="mybaentity.mapper.OneToOneMapper">

<select id="getUertByName" parameterType="String" resultMap="byname">
select * from user u,city c where u.cityid = c.cityid and username =
#{username}
</select>
<resultMap type="User" id="byname">
    <result property="userid" column="userid" />
    <result property="username" column="username" />
    <result property="possword" column="possword" />
    <result property="email" column="email" />
    <result property="phone" column="phone" />
    <association property="city" column="cityid" javaType="City"
        resultMap="cityResult" />
</resultMap>
<resultMap type="City" id="cityResult">
    <result property="cityid" column="cityid" />
    <result property="cityname" column="cityname" />
</resultMap>
    
    
    
    
    
    
<!-- <select id="getUertByName" parameterType="String" resultMap="byname">
    select * from user where username = #{username}
</select>

<resultMap type="User" id="byname">
    
        property:嵌套查询返回的结果赋值给当前类的哪个属性
        column:数据库中外检列的名字
        javaType:嵌套查询返回的结果集类型
        select:要嵌套的查询select元素的id值
    
    <association property="city" column="cityid" javaType="City" select="cityselect"/>
</resultMap>

<select id="cityselect" parameterType="int" resultType="City">
    select * from city where cityid = #{cityid}
</select> -->

</mapper>

六.增删改查

<mapper namespace="mybaentity.mapper.UserManagerMapper">

<select id="getUser" parameterType="map" resultType="User">
select * from user where username = #{k_username} and possword = #{k_possword}
</select>

<!-- 添加 -->
<insert id="insertUser">
insert into user(username,possword,email,phone) values(#{username},#{possword},#{email},#{phone})
</insert>
<!-- 删除一个 -->
<delete id="deleteUser">
delete from user where userid = #{userid}
</delete>
<!-- 删除多个 -->
<delete id="deleteUserAll">
    delete from user where userid in
    <!-- 
    遍历数组或者集合
    collection：元素的参数类型   
    item：条件 (当前遍历的元素)   
    open：得到（   (得到的元素以什么字符开始) 
    close得到） (得到的元素以什么字符结束)
    separator：用，号分割(用什么来分割)
     -->

    <foreach collection="array" item="userid" open="(" close=")" separator=",">
        #{userid}
    </foreach>
</delete>   
<!-- 修改 -->
<update id="updateUser">
update user set username = #{username},possword = #{possword},email = #{email} where userid = #{userid} 
</update>

</mapper>

七.一对多

<mapper namespace="mybaentity.mapper.OneMoreMapper">
<select id="getProvinceByName" parameterType="int" resultMap="pro_mapper">
select * from Province p,city c where p.pr_id=c.pr_id and p.pr_id =
#{p.pr_id}
</select>
<resultMap type="Province" id="pro_mapper">

    <!-- 一对多：property：返回集合赋值给当前类的哪个属性
          ofType:集合当中每个元素的类型 -->
    
    <result column="pr_id" property="pr_id" />
    <result column="pr_name" property="pr_name" />
    <collection property="cities" ofType="City">
    <result column="cityid" property="cityid"/>
    <result column="cityname" property="cityname"/>
    </collection>
</resultMap>

</mapper>

八.动态SQL

<mapper namespace="mybaentity.mapper.DynamicSelectMapper">

<select id="get" parameterType="User" resultType="user">
select * from user
<where>
<if test="city.cityid !=null and city.cityid !=0">
and cityid = #{city.cityid}
</if>
<if test="email!=null and email !=''">
and email = #{email}
</if>
<if test="phone!=null and phone !=''">
and phone = #{phone}
</if>
</where>
</select>
</mapper>

图片.png