mybatis 用原始的dao方法开发

程序员需要开发dao接口和dao的实现类

编写User.xml映射文件：

<select id="findUserById" parameterType="int" resultType="com.mo.pojo.User">
  SELECT * FROM USER  WHERE id = #{id}
</select>
<insert id="insertUser" parameterType="com.mo.pojo.User" >
  INSERT INTO USER (id,username,sex) VALUES (#{id},#{username},#{sex})
</insert>

Dao接口和实现类：

public interface UserDao {
  User findUserById(int id) throws IOException ;
  void insertUser(User user);
}

public class UserDaoImpl implements UserDao {

  //注入SqlSessionFactory成为成员变量，是使用了单例模式的
  private SqlSessionFactory sqlSessionFactory;
  
  //创建一个新的UserDaoImpl需要一个SqlSessionFactory实现
  public UserDaoImpl(SqlSessionFactory sqlSessionFactory){
    this.sqlSessionFactory = sqlSessionFactory;
  }
  
  public User findUserById(int id) throws IOException {
    //通过sqlSessionFactory会话工厂获取sqlSession来获取数据库相关的操作
    SqlSession sqlSession = sqlSessionFactory.openSession();
    User user = sqlSession.selectOne("test.findUserById", id);
    return user;
  }

  public void insertUser(User user) {
    //获取sqlSession,进行相关的数据库操作
    SqlSession sqlSession = sqlSessionFactory.openSession();
    sqlSession.insert("test.insertUser", user);
  }

}

单元测试

public class TestDao {
  
  //这里需要创建sqlSessionFactory工厂，因为创建新的UserDaoImpl需要注入会话工厂
  private SqlSessionFactory sqlSessionFactory;
  
  
  @Before
  public void setUp() throws IOException{
    String resource = "SqlMapConfig.xml";
    InputStream inputStream = Resources.getResourceAsStream(resource); 
    sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
  }
  
  @Test
  public void test() throws IOException{
    //这里需要注入一个sqlSessionFactory才能创建对象
    UserDao userdao = new UserDaoImpl(sqlSessionFactory);
    User user = userdao.findUserById(4);
    System.out.println(user);
  }
  
  @Test
  public void test1(){
    UserDao userdao = new UserDaoImpl(sqlSessionFactory);
    User user = new User();
    user.setId(9);
    user.setUsername("bushi");
    user.setSex("男");
    userdao.insertUser(user);
  }
}