idea开发必须是把Mapper文件与配置文件放到Resources标记的classpath目录下，eclips好像放到哪都行指定好路径就可以了，

maven里面做好配置resources的路径，不然更新依赖  工程结构标记又没了

       
          
             
       
        src/main/java/Resources
            
         
      
    

1.原生使用sqlsessionFcatory去做数据库操作，很麻烦

@Test    public void qeryByNameTest() throws IOException {        //加载核心配置文件        InputStream inputStream = Resources.getResourceAsStream("SqlMapConfig.xml");        //创造sqlsessionFactory        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);        SqlSession sqlSession = sqlSessionFactory.openSession();        List
     
       list= sqlSession.selectList("user.queryByName","王五");        for (User u:list){            System.out.println(u.toString());        }
     

2.使用mapper动态代理由mybatis根据你的 mapper类的接口名与映射文件里面的id名一致，指明了namespace的是哪个mapper类即可

public interface UserMapper {    //遵循四个原则    //接口 方法名  == User.xml 中 id 名    //返回值类型  与  Mapper.xml文件中返回值类型要一致    //方法的入参类型 与Mapper.xml中入参的类型要一致    //命名空间 绑定此接口    public User queryById(Integer id);}@Test  public  void  userMapperTest(){    InputStream inputStream = null;    {        try {            inputStream = Resources.getResourceAsStream("SqlMapConfig.xml");        } catch (IOException e) {            e.printStackTrace();        }    }    //创造sqlsessionFactory    SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);    SqlSession sqlSession= sqlSessionFactory.openSession();    UserMapper userMapper=sqlSession.getMapper(UserMapper.class);   User user= userMapper.queryById(10);    System.out.println(user);}

 

 SqlMapConfig.xml 
      
          
           
       
           
           
                
                
            
           
           
               
                    
                     
                     
                     
                         
                          
                          
                          
                      
                 
            
       
       
           
              
          
        
        
       
       UserMapper.xml

       
       
       
           
            select  * from user where  id=#{v}    
            
            
            select  *  from `user` where username like  '%${value}%'       
            
            
            
            
            
            
                
         
                      SELECT LAST_INSERT_ID()        
                 INSERT INTO `user`        (username,birthday,sex,address) VALUES        (#{username},#{birthday},#{sex},#{address})    
            
        
               UPDATE `user` SET    username = #{username}  WHERE id = #{id}    
            
            
        
                 delete from user where        id=#{id}