MyBatis核心配置文件及mapper配置等

MyBatis核心配置文件

获取SqlSession对象

public class MybatisUtil {
    private static SqlSessionFactory sqlSessionFactory ;
    static{
        try {
            //MyBatis核心配置文件路径
            String resource = "mybatis-config.xml";
            //文件流
            InputStream inputStream = Resources.getResourceAsStream(resource);
            //获取sqlSessionFactory对象
            sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //通过sqlSessionFactory对象获取SqlSession
    public static SqlSession getSqlSession(){
        return sqlSessionFactory.openSession();
    }


}

  
    select * from Blog where id = #{id}
  

测试案例

public class UserDaoTest {
    @Test
    public void test(){
        //第一步获取sqlSession对象
        SqlSession sqlSession = MybatisUtil.getSqlSession();
        try {
            //执行sql
            UserMapper mapper = sqlSession.getMapper(UserMapper.class);
            //获取结果
            List userList = mapper.getUserList();
            //遍历结果
            for (User user : userList) {
                System.out.println(user);
            }
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            //关闭sqlSession
            sqlSession.close();
        }
    }

    @Test
    public void getUserById(){
        //第一步获取sqlSession对象
        SqlSession sqlSession = MybatisUtil.getSqlSession();
        try {
            //执行sql
            UserMapper mapper = sqlSession.getMapper(UserMapper.class);
            //获取结果
            User userById = mapper.getUserById(1);
            //输出结果
            System.out.println(userById);
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            //关闭sqlSession
            sqlSession.close();
        }
    }

    @Test
    public void addUser(){
        //第一步获取sqlSession对象
        SqlSession sqlSession = MybatisUtil.getSqlSession();
        try {
            //执行sql
            UserMapper mapper = sqlSession.getMapper(UserMapper.class);
            //获取结果
            int conut = mapper.addUser(new User(4, "牛牛", "1212"));
            if(conut >0)System.out.println("添加成功");
            //提交事务 ，这里必须手动提交事务，不然添加不成功 ,增删改都需要提交事务
            sqlSession.commit();
        }catch (Exception e){
            e.printStackTrace();
        }finally {

            //关闭sqlSession
            sqlSession.close();
        }
    }

    @Test
    public void updateUser(){
        //第一步获取sqlSession对象
        SqlSession sqlSession = MybatisUtil.getSqlSession();
        try {
            //执行sql
            UserMapper mapper = sqlSession.getMapper(UserMapper.class);
            //获取结果
            int conut = mapper.updateUser(new User(4, "龙龙", "9999"));
            if(conut >0)System.out.println("修改OK");
            //提交事务 ，这里必须手动提交事务，不然添加不成功
            sqlSession.commit();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            //关闭sqlSession
            sqlSession.close();
        }
    }

    @Test
    public void deleteUser(){
        //第一步获取sqlSession对象
        SqlSession sqlSession = MybatisUtil.getSqlSession();
        try {
            //执行sql
            UserMapper mapper = sqlSession.getMapper(UserMapper.class);
            //获取结果
            int conut = mapper.deleteUser(4);
            if(conut >0)System.out.println("删除成功");
            //提交事务 ，这里必须手动提交事务，不然添加不成功
            sqlSession.commit();
        }catch (Exception e){
            e.printStackTrace();
        }finally {

            //关闭sqlSession
            sqlSession.close();
        }
    }
}