Mybatis 初识

mybatis跟hibernate一样，是持久层方面的，简单点就是数据库连接

mybatis-config.xml : 引入资源文件。然后配置环境，mybatis可以有多个环境，环境配置事务管理、jdbc，datasource

mybatisUtil：建立sessionFactory，再open，获取sqlSeesion

public class MybatisUtils {

    private static SqlSessionFactory sessionFactory;
    
    public static SqlSessionFactory getSessionFactory() throws Exception{
        InputStream inputStream= Resources.getResourceAsStream("mybatis-config.xml");
        sessionFactory=new SqlSessionFactoryBuilder().build(inputStream);
        return sessionFactory;
    }
    
    public static SqlSession openSqlSession() throws Exception{
        return getSessionFactory().openSession();
    }
}

mapper文件：对应接口的方法。

  
	
	
	



	insert into student values(null,#{username},#{password})


 
	update student set username=#{username} ,password=#{password} where id=#{id}



	delete from student where id=#{id}


 
	select * from student where id=#{id}
  

 
	select * from student
  

test文件：

  @Test
    public void add() throws Exception{
        Logger logger=Logger.getLogger(test.class);
        SqlSession session=MybatisUtils.openSqlSession();
        StudentMapper studentMapper = session.getMapper(StudentMapper.class);
        int result=  studentMapper.add(new Student( "cai1", "123"));
        if(result==1) logger.info("添加成功");
        session.commit();
    }
    @Test
    public void delete() throws Exception{
        Logger logger=Logger.getLogger(test.class);
        SqlSession session=MybatisUtils.openSqlSession();
        StudentMapper studentMapper = session.getMapper(StudentMapper.class);
        int result=  studentMapper.delete(new Student(2));
        if(result==1) logger.info("添加成功");
        session.commit();
    }
    @Test
    public void update() throws Exception{
        Logger logger=Logger.getLogger(test.class);
        SqlSession session=MybatisUtils.openSqlSession();
        StudentMapper studentMapper = session.getMapper(StudentMapper.class);
        int result=  studentMapper.update(new Student(4,"caica222i","123"));
        if(result==1) logger.info("添加成功");
        session.commit();
    }
    @Test
    public void findById() throws Exception{
        Logger logger=Logger.getLogger(test.class);
        SqlSession session=MybatisUtils.openSqlSession();
        StudentMapper studentMapper = session.getMapper(StudentMapper.class);
        List studentList =  studentMapper.findById(new Student(5));
        logger.info("添加成功");
        System.out.println(studentList);
        session.commit();
    }
    @Test
    public void select() throws Exception{
        Logger logger=Logger.getLogger(test.class);
        SqlSession session=MybatisUtils.openSqlSession();
        StudentMapper studentMapper = session.getMapper(StudentMapper.class);
        List studentList =  studentMapper.select();
        logger.info("添加成功");
        System.out.println(studentList);
        session.commit();
    }

接口：

public interface StudentMapper {

    public int add(Student student);
    public int delete(Student Student);
    public int update(Student student);
    public List select();
    public List findById(Student student);
}