The first day of the first test framework code MyBatis

Only used when using mybatis alone, the last ssm integration without writing code below

IS = Resources.getResourceAsStream InputStream ( "MyBatis.xml" ); // read the profiles created
 // use factory design pattern 
SqlSessionFactory Factory's new new the SqlSessionFactoryBuilder = () Build (IS);.
 // production 
SqlSession SqlSession session = factory. the openSession ();
 
List <Object> = session.selectList List ( "com.lhf.mapper.UserMapper.selectAll");

for(Object object:list){
        System.out.println(((User)object).getUname());
    }

session.close();
is.close();

Three kinds of query 

  1.selectList () returns a value of List <resultType property controls>
       1.1 applies to the query results need to traverse demand

List<Object> list=session.selectList("com.lhf.mapper.UserMapper.selectAll");
    for(Object object:list){
        System.out.println(((User)object).getUname());
    }

2.selectOne () Return Value Object,
    2.1 applies to only return results or variable data row

 

    User user = session.selectOne("com.lhf.mapper.UserMapper.selectOne");
    System.out.println(user);

3.selectMap () Returns the value of the Map
   is suitable for the need to take a value to a column line of data in the query results demand 3.1.
   3.2Map <Key, the resultType control>

Map<Object,Object> map = session.selectMap("com.lhf.mapper.UserMapper.selectMap","uname");//后面的是(Value,Key)
      System.out.println(map);