1.mybatis中查询方式有3种

//查询单个值    @Test    public void testFindOne()throws IOException{        SqlSession session = MybatisUtil.getSqlSession();        User user = (User)session.selectOne("cn.sxt.vo.UserMapper.findOne", 1);        System.out.println(user);        session.close();    }    //查询list    @Test    public void testFindAll() throws IOException{        SqlSession session = MybatisUtil.getSqlSession();        List
     
       list = session.selectList("cn.sxt.vo.UserMapper.findAll");        for(User u:list){            System.out.println(u);        }        session.close();    }    //查询map    @Test    public void testFindMap()throws IOException{        SqlSession session = MybatisUtil.getSqlSession();        //selectMap 传递的参是 map集合的key值。        Map map=session.selectMap("cn.sxt.vo.UserMapper.findMap", "name");        for(Iterator iter=map.keySet().iterator();iter.hasNext();){            Object key=iter.next();            System.out.println(key+"---"+map.get(key));        }        session.close();    }
     

映射文件

     
         
          
              select * from t_user where id=#{id}        
          
              select * from t_user        
          
              select * from t_user where id=1        
          
              select * from t_user limit #{begin},#{size}        
              select * from t_user    
     

2.分页

mybatis中有3种方式实现分页

映射文件

        select * from t_user limit #{begin},#{size}                select * from t_user    

代码

//通过sql语句进行分页,参数传入的是对象    @Test    public void testPage() throws IOException{        SqlSession session = MybatisUtil.getSqlSession();        PageInfo pi = new PageInfo();        pi.setBegin(3);        pi.setSize(3);        List
     
       list = session.selectList("cn.sxt.vo.UserMapper.page1",pi);        for(User u:list){            System.out.println(u);        }    }    //通过sql语句进行分页，参数传入的是map    @Test    public void testPage1() throws IOException{        SqlSession session = MybatisUtil.getSqlSession();        Map map = new HashMap();        map.put("begin", 0);        map.put("size", 3);        List
      
        list = session.selectList("cn.sxt.vo.UserMapper.page1",map);        for(User u:list){            System.out.println(u);        }    }    //通过RowBounds来实现分页     @Test    public void testPage2() throws IOException{        SqlSession session = MybatisUtil.getSqlSession();        //第一个 参数 相当于index,第二个参数 每页显示记录数        RowBounds bounds = new RowBounds(3, 3);        List
       
         list = session.selectList("cn.sxt.vo.UserMapper.pageRow",null,bounds);        for(User u:list){            System.out.println(u);        }    }