public static void testBasicQuery(int id) {
    SqlSession session = MybatisUtils.getSqlSession();
    try {
      /*
       * 此处的david.mybatis.demo.IVisitorOperation.basicQuery必须和下图中配置里面的namespace对应
       */
      Visitor visitor = (Visitor) session.selectOne("david.mybatis.demo.IVisitorOperation.basicQuery", id);
      MybatisUtils.closeSession(session);
      System.out.println(visitor);
    } catch (Exception e) {
      // TODO: handle exception
    }
  }

<!-- 此处namespace对应的就是你所传的String参数 -->
<mapper namespace="david.mybatis.demo.IVisitorOperation">
<!-- 此处的resultType就是对应刚刚你在typeAlias节点里面规定的别名 -->
  <select id="basicQuery" parameterType="int" resultType="Visitor">
    select * from visitor where id=#{id} and
    Status>0 order by Id
  </select>
</mapper>

package david.mybatis.demo;

import java.util.List;

import david.mybatis.model.PagenateArgs;
import david.mybatis.model.Visitor;

public interface IVisitorOperation {  
  /*
   * 基础查询
   */
  public Visitor basicQuery(int id);
}

  public static void testBasicQueryByInterfaceWay(int id) {
    SqlSession session = MybatisUtils.getSqlSession();
    try {
      IVisitorOperation vOperation = session.getMapper(IVisitorOperation.class);
      Visitor visitor = vOperation.basicQuery(id);
      MybatisUtils.closeSession(session);
      System.out.println(visitor);
    } catch (Exception e) {
      // TODO: handle exception
    }
  }

  /*
   * 基础查询
   */
  public Visitor basicQuery(int id);

  /*
   * 添加访问者
   */
  public int add(Visitor visitor);
  
  /*
   * 删除访问者
   */
  public int delete(int id);
  
  /*
   * 更新访问者
   */
  public int update(Visitor visitor);
  
  /*
   * 查询访问者
   */
  public Visitor query(int id);
  
  /*
   * 查询访问者List
   */
  public List<Visitor> getList();

<?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="david.mybatis.demo.IVisitorOperation">
  <!-- 
    useGeneratedKeys="true"代表是否使用自增长序列, 
    keyProperty="Id"指定自增长列是哪一列, 
    parameterType="Visitor"指定IVisitorOperation接口类中定义中所传的相应类型
    resultType 表示返回的类型，例如query中的visitor
    resultMap 自定义的返回类型，是返回复杂类型是的最佳首选，也是mybatis里最强大的武器
   -->
  <insert id="add" parameterType="Visitor" useGeneratedKeys="true"
    keyProperty="Id">
    insert into Visitor (Name, Email, Status, CreateTime)
    values (#{name}, #{email}, #{status}, #{createTime})
  </insert>
  <delete id="delete" parameterType="int">
    delete from Visitor where
    status>0 and id = #{id}
  </delete>
  <update id="update" parameterType="Visitor">
    update Visitor set Name =
    #{name}, Email=#{email}, Status=#{status} where id=#{id} and Status>0;
  </update>
  <select id="query" parameterType="int" resultType="Visitor">
    select Id,
    Name, Email, Status, CreateTime from visitor where id=#{id} and
    Status>0 order by Id
  </select>
  <select id="basicQuery" parameterType="int" resultType="Visitor">
    select * from visitor where id=#{id} and
    Status>0 order by Id
  </select>
  <select id="getList" resultMap="visitorRs">
    <include refid="getListSql" />
  </select>
  <resultMap type="Visitor" id="visitorRs">
    <id column="Id" property="id" />
    <result column="Name" property="name" />
    <result column="Email" property="email" />
    <result column="Status" property="status" />
    <result column="CreateTime" property="createTime" />
  </resultMap>
  <sql id="getListSql">
    select * from Visitor where
    status>0
  </sql>
</mapper>

<settings>
  <setting name="mapUnderscoreToCamelCase" value="false" />
</settings>

<mapper namespace="david.mybatis.demo.IVisitorOperation">
  <sql id="getListSql">
    select id as visitor_id, name, email, status, createtime from Visitor where
    status>0
  </sql>
  <select id="getList" resultMap="visitorRs">
    <include refid="getListSql" />
  </select>
  <!-- 
    这里指的注意的地方是property属性，里面的字段一定要和你在实体里面定义的属性一样，此处区分大小写
    否则会出现默认setter为属性赋值的时候找不到相应属性的异常，大家可以试下
    column属性对应于查询语句返回结果集的名字，如果有为相应字段起过别名例如吧id变为了visitor_id
    那么相应的column名字也要对应上
  -->
  <resultMap type="Visitor" id="visitorRs">
    <id column="visitor_id" property="id" />
    <result column="Name" property="name" />
    <result column="Email" property="email" />
    <result column="Status" property="status" />
    <result column="CreateTime" property="createTime" />
  </resultMap>
</mapper>

package david.mybatis.demo;

import java.util.Arrays;
import java.util.List;
import org.apache.ibatis.session.SqlSession;
import david.mybatis.model.BasicQueryArgs;
import david.mybatis.model.CRUD_Enum;
import david.mybatis.model.Channel;
import david.mybatis.model.PagenateArgs;
import david.mybatis.model.Visitor;
import david.mybatis.model.Website;

public class DemoRun {

  public static void testBasicQuery(int id) {
    SqlSession session = MybatisUtils.getSqlSession();
    try {
      /*
       * 此处的david.mybatis.demo.IVisitorOperation.basicQuery必须和下图中配置里面的namespace对应
       */
      Visitor visitor = (Visitor) session.selectOne("david.mybatis.demo.IVisitorOperation.basicQuery", id);
      MybatisUtils.closeSession(session);
      System.out.println(visitor);
    } catch (Exception e) {
      // TODO: handle exception
      e.printStackTrace();
    }
  }
  
  public static void testBasicQueryByInterfaceWay(int id) {
    SqlSession session = MybatisUtils.getSqlSession();
    try {
      IVisitorOperation vOperation = session.getMapper(IVisitorOperation.class);
      Visitor visitor = vOperation.basicQuery(id);
      MybatisUtils.closeSession(session);
      System.out.println(visitor);
    } catch (Exception e) {
      // TODO: handle exception
      e.printStackTrace();
    }
  }

  /*
   * 批量添加访问者记录
   */
  public static void addVisitors() {
    SqlSession session = MybatisUtils.getSqlSession();
    List<Visitor> visitors = Arrays.asList(new Visitor[] { new Visitor("mongodb", "mongodb@gmail.com"),
        new Visitor("redis", "redis@gmail.com"), new Visitor("memcached", "memcached@gmail.com"),
        new Visitor("CouchDB", "CouchDB@gmail.com"), new Visitor("HBase", "HBase@gmail.com"),
        new Visitor("Bigtable", "Bigtable@gmail.com"), new Visitor("Hive", "Hive@gmail.com"),
        new Visitor("MapReduce", "MapReduce@gmail.com"), });

    for (Visitor visitor : visitors) {
      addVisitor(visitor, session);
    }
    MybatisUtils.closeSession(session);
    MybatisUtils.showMessages(CRUD_Enum.List, visitors.size());
  }

  /*
   * 添加访问者信息
   */
  @SuppressWarnings("unused")
  private static void addVisitor(Visitor visitor, SqlSession session) {
    if (session == null)
      session = MybatisUtils.getSqlSession();
    IVisitorOperation vOperation = session.getMapper(IVisitorOperation.class);
    int recordCount = vOperation.add(visitor);
    session.commit();
    if (session == null)
      MybatisUtils.closeSession(session);
    MybatisUtils.showMessages(CRUD_Enum.Add, recordCount);
  }

  /*
   * 重载添加访问者
   */
  public static void addVisitor(Visitor visitor) {
    addVisitor(visitor, null);
  }

  /*
   * 删除访问者信息
   */
  public static void deleteVisitor(int id) {
    SqlSession session = MybatisUtils.getSqlSession();
    IVisitorOperation vOperation = session.getMapper(IVisitorOperation.class);
    int recordCount = vOperation.delete(id);
    session.commit();
    MybatisUtils.closeSession(session);
    MybatisUtils.showMessages(CRUD_Enum.Delete, recordCount);
  }

  /*
   * 更新访问者信息
   */
  public static void updateVisitor(int id) {
    SqlSession session = MybatisUtils.getSqlSession();
    IVisitorOperation vOperation = session.getMapper(IVisitorOperation.class);
    Visitor visitor = vOperation.query(id);
    System.out.println("原始对象：" + visitor);
    String name = visitor.getName();
    if (name.contains("updated")) {
      visitor.setName(name.substring(0, name.indexOf("updated")));
    } else {
      visitor.setName(name + "updated");
    }
    int recordCount = vOperation.update(visitor);
    session.commit();
    MybatisUtils.closeSession(session);
    MybatisUtils.showMessages(CRUD_Enum.Update, recordCount);
    System.out.println("更新后对象：" + visitor);
  }

  /*
   * 查询访问者信息
   */
  public static void queryVisitor(int id) {
    SqlSession session = MybatisUtils.getSqlSession();
    IVisitorOperation vOperation = session.getMapper(IVisitorOperation.class);
    Visitor visitor = vOperation.query(id);
    MybatisUtils.closeSession(session);
    MybatisUtils.showMessages(CRUD_Enum.Query, 1);
    System.out.println(visitor);
  }

  /*
   * 查询访问者列表
   */
  public static void queryVisitorList() {
    SqlSession session = MybatisUtils.getSqlSession();
    IVisitorOperation vOperation = session.getMapper(IVisitorOperation.class);
    List<Visitor> visitors = vOperation.getList();
    for (Visitor visitor : visitors) {
      System.out.println(visitor);
    }
    MybatisUtils.closeSession(session);
    MybatisUtils.showMessages(CRUD_Enum.List, visitors.size());
  }  
}