<?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="mapper.UserMapper">
        <select id="selectAll" resultType="model.User">
            select * from user
        </select>

        <select id="selectById" resultType="model.User">
            select  * from user where id=#{id}
        </select>
</mapper>

package mapper;

import model.User;
import java.util.List;

public interface UserMapper {
    List<User> selectAll();  //默認(rèn)public關(guān)鍵字修飾，selectAll對應(yīng)xml的id屬性

}

<?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">
      <!--連接配置->
        <property name="driver" value="${driver}"/>
        <property name="url" value="${url}"/>
        <property name="username" value="${username}"/>
        <property name="password" value="${password}"/>
      </dataSource>
    </environment>
  </environments>
  <mappers>
 	<!--mappper映射路徑-->
    <mapper resource="UserMapper.xml"/>
  </mappers>
</configuration>

package mybatis;
import mapper.UserMapper;
import model.User;

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 org.junit.Test;

import java.io.IOException;
import java.io.InputStream;
import java.util.List;

public class MybatisTest {

    @Test
    public void method() throws IOException {     //單元測試不能要static
        //mybatis框架都在xml配置文件中加載配置文件
        //從 XML 文件中構(gòu)建 SqlSessionFactory 的實(shí)例
        String resource = "mybatis-config.xml";
        InputStream inputStream = null;

        inputStream = Resources.getResourceAsStream(resource);

        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);

        //從 SqlSessionFactory 中獲取 SqlSession
        SqlSession session = sqlSessionFactory.openSession();


        //執(zhí)行sql
        //List<User> users=session.selectList("test.selectAll");
        //System.out.println(users);

        //mapper代理執(zhí)行sql
        UserMapper userMapper=session.getMapper(UserMapper.class);
        List<User> users= userMapper.selectAll();  //UserMapper接口的實(shí)現(xiàn)方法
        System.out.println(users);

        //釋放資源
        session.close();

    }
}

<select id="selectAll" resultType="model.User">
	select * from user
</select>

<select id="selectById" resultType="model.User">
    select  * from user where id=#{id}
</select>

<select id="selectmore" resultType="model.User">
    select * from user where id =#{id} and username=#{username}
</select>

List<User> selectAll();  //默認(rèn)public關(guān)鍵字修飾
List<User> selectById(int id);
List<User> selectMore(int id,String name);