mybatis_2

 <?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">
   <!-- 全局配置文件 -->
 <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?characterEncoding=utf8"/>
         <property name="username" value="root"/>
         <property name="password" value="root"/>
       </dataSource>
     </environment>
   </environments>

   <!-- 加载映射文件 -->
   <mappers>
     <mapper resource="EmployeeMapper1.xml"/>
     <mapper resource="EmployeeMapper2.xml"/>
   </mappers>
 </configuration>

package demo2;

import entity.Employee;

public interface EmployeeMapper {
public Employee getById(int id);
}

 <?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">

 <!-- demo2 -->
 <mapper namespace="com.demo2.EmployeeMapper">
     <!--
             mybatis 支持命名空间设置为 dao 接口 进行绑定   框架会自动对接口进行代理  不需要手动实例化
                     sql 唯一id与接口中的方法进行绑定  这里的接口只需要设定好方法的参数而不需要实例化
      -->
       <select id="getById" resultType="org.entity.Employee">
         select * from employee where id = #{id}
       </select>
 </mapper>

 package demo2;

 import java.io.IOException;
 import java.io.InputStream;

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

 public class Demo2 {

     public static void main(String[] args) throws IOException {
         // 1、获取sessionFactory
         String resource = "mybatis-config.xml";
         InputStream inputStream = Resources.getResourceAsStream(resource);
         SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder()
                 .build(inputStream);
         // 2、获取 session
         SqlSession session = sqlSessionFactory.openSession();
         // 3、获取接口的是实现类对象 自动代理
         EmployeeMapper mapper = session.getMapper(EmployeeMapper.class);

         Employee employee = mapper.getById(1);
         System.out.println(employee.toString());
         session.close();
     }
 }