MyBatis1之基础

MyBatis的方法一

//创建SqlsessionFactoryBuilder对象
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder();
//创建核心配置文件的输入流
InputStream inputStream = Resources.getResourceAsStream(“SqlMapconfig.xml”);
//通过输入流，创建SqlSessionFactory对象
SqlSessionFactory sqlSessionFactory = ssfb.build(inputStream);
//创建SqlSession对象
SqlSession sqlSession = sqlSessionFactory.openSession();
//执行查询
User user =sqlSession.selectOne(“user.getUserById”,1);
System.out.print(user);
//释放资源
sqlSession.close();
方法一：通过selectOne的方法，配置POJO User类，配置user.xml，然后实现SQL语句。

这里可以封装Utils工具
SqlSessionFactoryBuilder ssfb = new SqlSessionFactoryBuilder();
//创建核心配置文件的输入流
InputStream inputStream = Resources.getResourceAsStream(“SqlMapconfig.xml”);
//通过输入流，创建SqlSessionFactory对象
SqlSessionFactory sqlSessionFactory = ssfb.build(inputStream);
返回sqlSession。

xml配置：
#{}:占位符，相当于jdbc的？
${}:字符串拼接指令，如果入参为普通数据类型{}内部只能写value

    
    
        SELECT 
        	`id`,
        	`username`,
        	`birthday`,
        	`sex`,
        	`address`
        FROM `user`
        WHERE id = #{id}
    
   
    
    
SELECT 
  `id`,
  `username`,
  `birthday`,
  `sex`,
  `address` 
FROM
  `heima`.`user` 
   
WHERE  `username` LIKE '%${value}%'     
    
    
       INSERT INTO USER
       		(`username`,
       		`birthday`,
       		`sex`,
       		`address`)
       VALUS
       (#{username},
		        #{birthday},
		        #{sex},
		        #{address});