使用接口结合xml文件

1)创建dao包，在包下创建接口，该接口要和映射文件匹配

1 package com.zhiyou.clg.dao;
2 import java.util.List;
3 import org.apache.ibatis.annotations.Param;
4 import com.zhiyou.clg.bean.User;
5 public interface UserDao {
6     List<User> selectUser2(int id);
7 }

2)映射文件中的namespace一定要和接口所在的包以及接口的名字一样

3)标签中的id一定和接口中方法的名字对照

1 <?xml version="1.0" encoding="UTF-8" ?>
2 <!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
3 "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
4 <mapper namespace="com.zhiyou.clg.dao.UserDao">
5     <select id="selectUser2" parameterType="int"
6         resultType="com.zhiyou.clg.bean.User">
7         select * from user where id=#{id}
8     </select>
9 </mapper>

4)测试：.

1 @Test
2     void testselectUser2() {
3         UserDao userDao = session.getMapper(UserDao.class);
4         List<User> list = userDao.selectUser2(1);
5         System.out.println(list);
6     }