import java.io.IOException;
import java.io.Reader;import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;/*** 访问数据库类*/
public class DBAccess {public SqlSession getSqlSession() throws IOException {//通过配置文件获取数据库连接信息Reader reader = Resources.getResourceAsReader("com/daoan/config/Configuration.xml");//通过配置信息构建SqlSessionFactoySqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);//通过SqlSessionFactoy打开一个数据库会话SqlSession sqlSession = sqlSessionFactory.openSession();return sqlSession;}
}

/*** 和Message表相关的数据库操作*/
public class MessageDao { /***  根据查询条件，查询消息列表*/public List<Message> queryMessageList(String command,String description) {DBAccess dbAccess = new DBAccess();List <Message> messageList = new ArrayList<Message>();SqlSession sqlSession = null;try {sqlSession = dbAccess.getSqlSession();//通过sqlSession执行SQL语句messageList = sqlSession.selectList("Message.queryMessageList");} catch (IOException e) {// TODO Auto-generated catch blocke.printStackTrace();} finally {if(sqlSession !=null){sqlSession.close();sqlSession = null;}}return messageList;}public static void main(String[] args) {MessageDao messageDao = new MessageDao();messageDao.queryMessageList("", "");}
}

<?xml version="1.0" encoding="UTF-8"?><!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd"><mapper namespace="Message"><resultMap type="com.daoan.bean.Message" id="MessageResult"><id column="Id" jdbcType="INTEGER" property="id"/><result column="Command" jdbcType="VARCHAR" property="command"/><result column="Description" jdbcType="VARCHAR" property="description"/><result column="Context" jdbcType="VARCHAR" property="context"/></resultMap><select id="queryMessageList" resultMap="MessageResult">select Id,Command,Description,Context from message where 1=1</select>
</mapper>