mybatis深入浅出之原始Dao开发

àì夳堔傛蜴生んèń 2022-03-24 16:20 299阅读 0赞

结合上一篇文章《mybatis深入浅出之增删改查》：[https://blog.csdn.net/weixin\_41477980/article/details/86593696][https_blog.csdn.net_weixin_41477980_article_details_86593696]和《SqlSession、SqlSessionFactory、SqlSessionFactoryBuilder使用时的注意事项》：[https://blog.csdn.net/weixin\_41477980/article/details/86594550][https_blog.csdn.net_weixin_41477980_article_details_86594550]继续深入浅出的学习mybatis。

原始Dao开发方法需要编写Dao接口和Dao实现类。

### **1.编写user.xml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"*>

<select id=*"queryUserById"* parameterType=*"int"*

resultType=*"cn.mybatis.pojo.User"*>

select \* from user where id = \#\{id\}

</select>

<select id=*"queryUserByUsername"* parameterType=*"string"*

resultType=*"cn.mybatis.pojo.User"*>

select \* from user where username like '%$\{value\}%'

</select>

<insert id=*"saveUser"* parameterType=*"cn.mybatis.pojo.User"*>

insert into user(username,birthday,sex,address)

values(\#\{username\},\#\{birthday\},\#\{sex\},\#\{address\})

</insert>

</mapper>

### 2.DAO接口开发 ###

**public** **interface** UserDao \{

// 根据id查询用户

User queryUserById(**int** id);

// 根据用户名模糊查询用户

List<User> queryUserByUsername(String username);

//保存用户

**void** saveUser(User user);

### 3.Dao实现类开发 ###

**public** **class** UserDaoImpl **implements** UserDao \{

**private** SqlSessionFactory sqlSessionFactory;

**public** UserDaoImpl(SqlSessionFactory sqlSessionFactory) \{

**super**();

**this**.sqlSessionFactory = sqlSessionFactory;

@Override

**public** User queryUserById(**int** id) \{

// 创建SqlSession

SqlSession sqlSession = **this**.sqlSessionFactory.openSession();

// 执行查询逻辑

User user = sqlSession.selectOne("queryUserById", id);

// 释放资源

sqlSession.close();

**return** user;

@Override

**public** List<User> queryUserByUsername(String username) \{

// 创建SqlSession

SqlSession sqlSession = **this**.sqlSessionFactory.openSession();

// 执行查询逻辑

List<User> list = sqlSession.selectList("queryUserByUsername", username);

// 释放资源

sqlSession.close();

**return** list;

@Override

**public** **void** saveUser(User user) \{

// 创建SqlSession

SqlSession sqlSession = **this**.sqlSessionFactory.openSession();

// 执行保存逻辑

sqlSession.insert("saveUser", user);

// 提交事务

sqlSession.commit();

// 释放资源

sqlSession.close();

\}\}

### 4.JUnit的测试类开发，对UserDao进行测试 ###

**public** **class** UserDaoTest \{

**private** SqlSessionFactory sqlSessionFactory;

@Before

**public** **void** init() **throws** Exception \{

// 创建SqlSessionFactoryBuilder

SqlSessionFactoryBuilder sqlSessionFactoryBuilder = **new** SqlSessionFactoryBuilder();

// 加载SqlMapConfig.xml配置文件

InputStream inputStream = Resources.*getResourceAsStream*("SqlMapConfig.xml");

// 创建SqlsessionFactory

**this**.sqlSessionFactory = sqlSessionFactoryBuilder.build(inputStream);

@Test

**public** **void** testQueryUserById() \{

// 创建DAO

UserDao userDao = **new** UserDaoImpl(**this**.sqlSessionFactory);

// 执行查询

User user = userDao.queryUserById(1);

System.***out***.println(user);

@Test

**public** **void** testQueryUserByUsername() \{

// 创建DAO

UserDao userDao = **new** UserDaoImpl(**this**.sqlSessionFactory);

// 执行查询

List<User> list = userDao.queryUserByUsername("张");

**for** (User user : list) \{

System.***out***.println(user);

\}\}

@Test

**public** **void** testSaveUser() \{

// 创建DAO

UserDao userDao = **new** UserDaoImpl(**this**.sqlSessionFactory);

// 创建保存对象

User user = **new** User();

user.setUsername("刘备");

user.setBirthday(**new** Date());

user.setSex("1");

user.setAddress("蜀国");

// 执行保存

userDao.saveUser(user);

System.***out***.println(user);

\}\}

[https_blog.csdn.net_weixin_41477980_article_details_86593696]: https://blog.csdn.net/weixin_41477980/article/details/86593696
[https_blog.csdn.net_weixin_41477980_article_details_86594550]: https://blog.csdn.net/weixin_41477980/article/details/86594550