這裏是最基本的搭建：http://www.cnblogs.com/xuyiqing/p/8600888.html

接下來做到了簡單的增刪改查：http://www.cnblogs.com/xuyiqing/p/8601506.html

但是發現代碼重復過多等問題

接下來整合並實現DAO開發：

一：原始DAO開發：

package dao;

import pojo.User;

public interface UserDao {
    public User selectUserById(Integer id);
}

package dao;

import java.util.List;
import
 
 org.apache.ibatis.session.SqlSession;
import org.apache.ibatis.session.SqlSessionFactory;

import pojo.User;

public class UserDaoImpl implements UserDao {

    //註入
    private SqlSessionFactory sqlSessionFactory;
    public UserDaoImpl(SqlSessionFactory sqlSessionFactory) {
        this.sqlSessionFactory = sqlSessionFactory;
    }
    
    
 
//通過用戶ID查詢一個用戶
    public User selectUserById(Integer id){
        SqlSession sqlSession = sqlSessionFactory.openSession();
        return sqlSession.selectOne("test.findUserById", id);
    }
    //通過用戶名稱模糊查詢
    public List<User> selectUserByUsername(Integer id){
        SqlSession sqlSession = sqlSessionFactory.openSession();
        
 
return sqlSession.selectList("test.findUserById", id);
    }
}

測試類：

package junit;

import java.io.InputStream;

import org.apache.ibatis.io.Resources;
import org.apache.ibatis.session.SqlSessionFactory;
import org.apache.ibatis.session.SqlSessionFactoryBuilder;
import org.junit.Before;
import org.junit.Test;

import dao.UserDao;
import dao.UserDaoImpl;
import pojo.User;

public class DaoTest {
    public SqlSessionFactory sqlSessionFactory;
    @Before
    public void before() throws Exception {
        String resource = "sqlMapConfig.xml";
        InputStream in = Resources.getResourceAsStream(resource);
        sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
    }
    @Test
    public void testDao() throws Exception {
        UserDao userDao = new UserDaoImpl(sqlSessionFactory);
        User user = userDao.selectUserById(10);
        System.out.println(user);
    }
}

但是還是發現代碼重復、浪費資源等問題：

於是想到Mapper動態代理開發：

package mapper;

import pojo.User;

public interface UserMapper {

    
    //遵循四個原則
    //接口 方法名  == User.xml 中 id 名
    //返回值類型  與  Mapper.xml文件中返回值類型要一致
    //方法的入參類型 與Mapper.xml中入參的類型要一致
    //命名空間 綁定此接口
    
    //這裏如果返回的是一個對象，則調用selectOne方法
    //如果是List，則調用selectlist方法
    public User findUserById(Integer id);
    
}

UserMapper.xml

<?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">
<!-- 寫Sql語句   -->
<mapper namespace="mapper.UserMapper">
    <!-- 通過ID查詢一個用戶 -->
    <select id="findUserById" parameterType="Integer" resultType="pojo.User">
        select * from user where id = #{v}
    </select>
    
    <!-- //根據用戶名稱模糊查詢用戶列表
    #{}    select * from user where id = ？    占位符  ? ==  ‘五‘
    ${}    select * from user where username like ‘%五%‘  字符串拼接  
    
     -->
    <select id="findUserByUsername" parameterType="String" resultType="pojo.User">
        select * from user where username like "%"#{haha}"%"
    </select>
    
    <!-- 添加用戶 -->
    <insert id="insertUser" parameterType="pojo.User">
        <selectKey keyProperty="id" resultType="Integer" order="AFTER">
            select LAST_INSERT_ID()
        </selectKey>
        insert into user (username,birthday,address,sex) 
        values (#{username},#{birthday},#{address},#{sex})
    </insert>
    
    <!-- 更新 -->
    <update id="updateUserById" parameterType="pojo.User">
        update user 
        set username = #{username},sex = #{sex},birthday = #{birthday},address = #{address}
        where id = #{id}
    </update>
    
    <!-- 刪除 -->
    <delete id="deleteUserById" parameterType="Integer">
        delete from user 
        where id = #{vvvvv}
    </delete>


</mapper>

主配置文件sqlMapConfig.xml：

<?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">
                <property name="driver" value="com.mysql.jdbc.Driver" />
                <property name="url"
                    value="jdbc:mysql://localhost:3306/mybatis?characterEncoding=utf-8" />
                <property name="username" value="root" />
                <property name="password" value="xuyiqing" />
            </dataSource>
        </environment>
    </environments>
    <mappers>
        <mapper resource="mapper/UserMapper.xml"/> 
    </mappers>
</configuration>

測試類：

package junit;
import java.io.InputStream;

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 mapper.UserMapper;
import pojo.User;

public class MybatisMapperTest {

    
    @Test
    public void testMapper() throws Exception {
        String resource = "sqlMapConfig.xml";
        InputStream in = Resources.getResourceAsStream(resource);
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(in);
        SqlSession sqlSession = sqlSessionFactory.openSession();
        
        //SqlSession自動為接口生成一個實現類 
        UserMapper userMapper = sqlSession.getMapper(UserMapper.class);
        User user = userMapper.findUserById(10);
        System.out.println(user);
    }
}

通常情況下，建議使用Mapper動態代理開發

Mybatis框架三：DAO層開發、Mapper動態代理開發