2.HelloWorld

1.创建一张测试表

2.创建对应的javaBean

3.创建MyBatista配置文件，sql映射文件
①导包

②创建xml配置文件（注意config目录文件夹是source类型的）

1.全局配置文件 mybatis.config.xml

<?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" />
                <property name="url" value="jdbc:mysql://localhost:3306/mybatis" />
                <property name="username" value="root" />
                <property name="password" value="abc123" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="EmployeeMapper.xml" />
    </mappers>
</configuration>

2.SQL映射文件

<?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="com.atguigu.mybatis.EmployeeMapper">
    <!--
    namespace:名称空间
    id:唯一标识
    resultType:返回值类型
    #{id}:从传递过来的参数中取出id值
     -->
    <select id="selectEmp" resultType="com.atguigu.mybatis.bean.Employee">
        select * from tbl_employee where id = #{id}
    </select>
</mapper>

3.log4j.xml

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE log4j:configuration SYSTEM "log4j.dtd">

<log4j:configuration xmlns:log4j="http://jakarta.apache.org/log4j/">

 <appender name="STDOUT" class="org.apache.log4j.ConsoleAppender">
   <param name="Encoding" value="UTF-8" />
   <layout class="org.apache.log4j.PatternLayout">
    <param name="ConversionPattern" value="%-5p %d{MM-dd HH:mm:ss,SSS} %m  (%F:%L) \n" />
   </layout>
 </appender>
 <logger name="java.sql">
   <level value="debug" />
 </logger>
 <logger name="org.apache.ibatis">
   <level value="info" />
 </logger>
 <root>
   <level value="debug" />
   <appender-ref ref="STDOUT" />
 </root>
</log4j:configuration>

4.测试
①根据全局配置文件，利用SqlSessionFactoryBuilder()创建SqlSessionFactory

②使用SqlSessionFactory获取SqlSession对象。一个SqlSession对象代表和数据库的一次会话

③使用SqlSession根据方法id进行操作
④关闭SqlSession对象