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和《SqlSession、SqlSessionFactory、SqlSessionFactoryBuilder使用时的注意事项》：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">
<!-- namespace：命名空间，用于隔离sql-->
<mapper namespace="test">
<!-- 根据id查询用户 -->
<select id="queryUserById" parameterType="int"
resultType="cn.mybatis.pojo.User">
select * from user where id = #{id}
</select>
<!-- 根据username模糊查询用户 -->
<select id="queryUserByUsername" parameterType="string"
resultType="cn.mybatis.pojo.User">
select * from user where username like '%${value}%'
</select>
<!-- 保存用户 -->
<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);
}}