MyBatis 原始Dao开发方式

原始Dao开发方法需要程序员编写Dao接口和Dao实现类。

映射文件

<?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="test">
<!-- 根据id获取用户信息 -->
    <select id="findUserById" parameterType="int" resultType="cn.itcast.mybatis.po.User">
        select * from user where id = #{id}
    </select>
<!-- 添加用户 -->
    <insert id="insertUser" parameterType="cn.itcast.mybatis.po.User">
    <selectKey keyProperty="id" order="AFTER" resultType="java.lang.Integer">
        select LAST_INSERT_ID()
    </selectKey>
      insert into user(username,birthday,sex,address)
      values(#{username},#{birthday},#{sex},#{address})
    </insert>
</mapper>

 

DAO接口

Public interface UserDao {
    public User getUserById(int id) throws Exception;
    public void insertUser(User user) throws Exception;
}

Public class UserDaoImpl implements UserDao {

    //注入SqlSessionFactory
    public UserDaoImpl(SqlSessionFactory sqlSessionFactory){
        this.setSqlSessionFactory(sqlSessionFactory);
    }

    private SqlSessionFactory sqlSessionFactory;
    @Override
    public User getUserById(int id) throws Exception {
        SqlSession session = sqlSessionFactory.openSession();
        User user = null;
        try {
            //通过sqlsession调用selectOne方法获取一条结果集
            //参数1：指定定义的statement的id,参数2：指定向statement中传递的参数
            user = session.selectOne("test.findUserById", 1);
            System.out.println(user);

        } finally{
            session.close();
        }
        return user;
    }

    @Override
    Public void insertUser(User user) throws Exception {
        SqlSession sqlSession = sqlSessionFactory.openSession();
        try {
            sqlSession.insert("insertUser", user);
            sqlSession.commit();
        } finally{
            session.close();
        }

    }
}