MyBatis的原始Dao开发-了解

使用Mybatis开发Dao，通常有两个方法，即原始Dao开发方式和Mapper接口代理开发方式。而现在主流的开发方式是接口代理开发方式，这种方式总体上更加简便。在之前的文章已经给大家介绍了基于代理方式的dao开发，现在给大家介绍一下基于传统编写Dao实现类的开发方式。

拷贝之前的工程：

1.创建接口

public interface UserDao {//查询所有User信息public List<User> findAll();//根据id查询Userpublic User findUserById(Integer id);//保存用户信息public void saveUser(User user);//修改用户public void updateUser(User user);//删除用户public void deleteUserById(Integer id);
}

2.创建接口实现类

public class UserDaoImpl implements UserDao {private SqlSession sqlSession;public UserDaoImpl(SqlSession sqlSession) {this.sqlSession = sqlSession;}public List<User> selectAll() {List<User> userList = sqlSession.selectList("com.wt.dao.UserDao.findAll");sqlSession.close();return userList;}public User selectUserById(Integer id) {User user = sqlSession.selectOne("com.wt.dao.UserDao.findUserById", id);sqlSession.close();return user;}public void saveUser(User user) {sqlSession.insert("com.wt.dao.UserDao.saveUser", user);sqlSession.commit();sqlSession.close();}public void updateUser(User user) {sqlSession.update("com.wt.dao.UserDao.updateUser", user);sqlSession.commit();sqlSession.close();}public void deleteUserById(Integer id) {sqlSession.delete("com.wt.dao.UserDao.deleteUserById", id);sqlSession.commit();sqlSession.close();}
}

3.定义映射文件

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mapperPUBLIC "-//mybatis.org//DTD Mapper 3.0//EN""http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.wt.dao.UserDao"><!--查询所有用户信息--><select id="findAll" resultType="com.wt.pojo.User">select * from user</select><!--根据id查询用户信息--><select id="findUserById" parameterType="int" resultType="com.wt.pojo.User">select * from user where id=#{id}</select><!--保存用户信息--><insert id="saveUser" parameterType="com.wt.pojo.User">insert into user(username,password,birthday,sex,address) values(#{username},#{password},#{birthday},#{sex},#{address});</insert><!--修改用户信息--><update id="updateUser" parameterType="com.wt.pojo.User">update user set username=#{username},birthday=#{birthday},sex=#{sex},address=#{address} where id=#{id}</update><!--删除用户--><delete id="deleteUserById" parameterType="int">delete from user where id=#{id}</delete>
</mapper>

4.测试

public class MyBatisTest {private InputStream inputStream;//数据库会话实例private SqlSession sqlSession;@Beforepublic void createSqlSession() throws IOException {//1.Resources：加载配置文件String resource = "SqlMapConfig.xml";inputStream = Resources.getResourceAsStream(resource);//2.SqlSessionFactoryBuilder：构建SqlSessionFactory工厂//3.sqlSessionFactory：创建SqlSession对象SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);//4.SqlSession：创建代理对象sqlSession = sqlSessionFactory.openSession();}@Testpublic void testFindAll() throws Exception{UserDao userDao = new UserDaoImpl(sqlSession);List<User> userList = userDao.findAll();for(User user : userList){System.out.println(user);}}@Testpublic void testFindUserById(){UserDao userDao = new UserDaoImpl(sqlSession);User user = userDao.findUserById(42);System.out.println(user);}@Testpublic void testSaveUser(){UserDao userDao = new UserDaoImpl(sqlSession);User user = new User();user.setUsername("张宇");user.setPassword("111");user.setBirthday(new Date());user.setSex("男");user.setAddress("台湾");userDao.saveUser(user);}@Testpublic void testUpdateUser(){UserDao userDao = new UserDaoImpl(sqlSession);User user = new User();user.setUsername("张二宇");user.setPassword("222");user.setBirthday(new Date());user.setSex("男");user.setAddress("香港");user.setId(50);userDao.updateUser(user);}@Testpublic void testDeleteUser(){UserDao userDao = new UserDaoImpl(sqlSession);userDao.deleteUserById(50);}@Afterpublic void closeSqlSession() throws IOException {sqlSession.close();inputStream.close();}
}