MyBatis入门（二）接口式编程

在  MyBatis入门（一） 的基础之上编写接口

将接口和Mapper文件进行绑定，会为接口创建一个代理对象，代理对象去执行增删改查

（1）编写接口

 public interface EmpDao {
 
     public Emp getEmp(Integer id);
 }

（2）修改Mapper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.eu.dao.EmpDao">
   <select id="getEmp" resultType="com.eu.pojo.Emp">
     select id,last_name lastName,gender,email from Emp where id = #{id}
   </select>
 </mapper>

（3）编写测试

 　　@Test
     public  void testMapper02() throws IOException {
         //1.获取SqlSessionFactory对象
         String resource = "conf/mybatis-config.xml";
         InputStream inputStream = Resources.getResourceAsStream(resource);
         SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
         //2.获取SqlSession对象
         SqlSession session = sqlSessionFactory.openSession();
         try {
             //3.获取接口的实现类对象
             EmpDao empDao = session.getMapper(EmpDao.class);
             Emp emp = empDao.getEmp(1);
             System.out.println(emp);
         } finally {
           session.close();
         }
     }

（4）运行结果

DEBUG 04-14 23:01:47,690 ==>  Preparing: select id,last_name lastName,gender,email from Emp where id = ?   (BaseJdbcLogger.java:145)
DEBUG 04-14 23:01:47,801 ==> Parameters: 1(Integer)  (BaseJdbcLogger.java:145)
DEBUG 04-14 23:01:47,842 <==      Total: 1  (BaseJdbcLogger.java:145)
Emp [id=1, lastName=张三, geder=null, email=we.com]