sqlMapConfig.xml的配置

<?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>

    <!-- 載入屬性檔案 -->
    <properties resource="db.properties">
        <!-- 可以配置屬性名和屬性值,這裡的屬性首先被讀取,然後會讀取屬性檔案
            ，同名屬性會覆蓋,最後讀取parameterType傳遞的屬性
        -->
 

    </properties>

    <!-- 別名 -->
    <typeAliases>
        <!-- 單個別名 -->
        <!--<typeAlias type="jack.po.User" alias="user"/>  -->
        <!--
             批量別名定義 
            指定包名，mybatis會自動掃描包中的po類，自動定義別名
            別名是類名(首字母大寫或者小寫都可)
        -->
        <package
 
 name="jack.po"/>
        <package name="jack.pojo"/>
    </typeAliases>

     <environments default="development">
         <environment id="development">
         <!-- 由mybatis控制事務 -->
             <transactionManager type="JDBC"/>
        <!-- 由mybatis控制連線池 -->
 

                 <dataSource type="POOLED">
                     <property name="driver" value="${jdbc.driver}"/>
                     <property name="url" value="${jdbc.url}"/>
                     <property name="username" value="${jdbc.username}"/>
                     <property name="password" value="${jdbc.password}"/>
                 </dataSource>
         </environment>
     </environments>

     <mappers>
        <!-- <mapper resource="sqlmap/User.xml"/> -->
        <!--<mapper resource="mapper/UserMapper.xml"/> -->
        <!-- 通過mapper介面載入對映檔案
            需要將mapper介面的名字和mapper.xml的檔案保持一致
            且在一個目錄
            前提上：使用的mapper代理的方式
         -->
        <!--  <mapper class="jack.user.mapper.UserMapper"/> -->
         <!-- 批量載入mapper,自動掃描包下的mapper -->

         <package name="jack.employee.mapper"/>
     </mappers>

</configuration>

使用mapper代理有以下要求：

1.對映檔案的namespace是介面的全路徑
2.方法名和配置檔案的statement的id對應
3.返回值型別和resulttype對應
4.引數型別和parameterType對應

先來寫EmployeeMapper.xml配置檔案

<!DOCTYPE mapper
 PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
 "http://mybatis.org/dtd/mybatis-3-mapper.dtd">
 <!-- namespance是介面的全路徑 -->
 <mapper namespace="jack.employee.mapper.EmployeeMapper">

    <!-- id和介面的方法名稱一致
        parameterType和輸入引數一致
        resultType和返回值一致
     -->
    <select id="getEmployeeById" parameterType="int" resultType="employee">
        select * from t_employee where id=#{id}
    </select>
    <insert id="insertToEmployee" parameterType="jack.pojo.Employee">
        insert into t_employee(name,birthday,sex,address) values(#{name},#{birthday},#{sex},#{address})
    </insert>
    <select id="getEmployeeByName" parameterType="String" resultType="employee">
        select * from t_employee where name like '%${value}%'
    </select>
    <select id="getEmloyee" parameterType="employee" resultType="employee">
        select e.name name_,e.birthday bir_ from t_employee e where e.name like '%${name}%' and e.sex=#{sex}
    </select>
    <select id="getEmloyee2" parameterType="employee" resultMap="employeeResMap">
        select e.name name_,e.birthday bir_ from t_employee e where e.name like '%${name}%' and e.sex=#{sex}
    </select>
    <resultMap type="employee" id="employeeResMap">
        <result column="name_" property="name"/>
        <result column="bir_" property="birthday"/>
    </resultMap>
 </mapper>

下面是EmployeeMapper介面程式碼:

package jack.employee.mapper;

import java.util.List;

import jack.pojo.Employee;

public interface EmployeeMapper {

    /**
     * 按照員工id查詢員工
     * */
    public Employee getEmployeeById(Integer id);

    /**
     * 插入一條員工記錄
     * */
    public void insertToEmployee(Employee employee);

    /**
     * 按照名稱模糊查詢
     * */
    public List<Employee> getEmployeeByName(String name);

    /**
     * 高階搜尋
     * */
    public List<Employee> getEmloyee(Employee employee);

    public List<Employee> getEmloyee2(Employee employee);
}

mybatis會自動幫我們生成實現類，代理物件,可以自己列印mapper物件看一下
測試程式碼如下:

package jack.employee.mapper;

import java.io.InputStream;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;

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.Before;
import org.junit.Test;

import jack.pojo.Employee;

public class EmployeeMapperTest {

    private SqlSessionFactory factory;

    @Before
    public void setUp() throws Exception {
        InputStream stream = Resources.getResourceAsStream("sqlMapConfig.xml");
        factory = new SqlSessionFactoryBuilder().build(stream);
    }


    @Test
    public void testGetEmployeeById() {
        /*mapper**/
        SqlSession session = factory.openSession();
        EmployeeMapper mapper = session.getMapper(EmployeeMapper.class);
        Employee e = mapper.getEmployeeById(1);
        System.out.println(e);
    }
}