MyBatis 是一款优秀的持久层框架,它支持自定义 SQL、存储过程以及高级映射。MyBatis 免除了几乎所有的 JDBC 代码以及设置参数和获取结果集的工作。
mysql
mysql-connector-java
8.0.33
org.mybatis
mybatis
3.5.6
在要使用mybatis的类中操作
String resource = "mybatis-config.xml";
InputStream inputStream = Resources.getResourceAsStream(resource);
SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream);
用来调用sql语句操作数据库
SqlSession sqlSession = sqlSessionFactory.openSession();
注意:
* 1.方法的名字与对象sql的id保持一致
* 2.对应xml的namespace值必须是对应接口的类型全名
List findAll();
Employee findById(int id);
Employee findByIdAndName(Map map);
Employee findByIdAndName(Employee employee);
//@Param()其实就是将参数封装为map对象,注解的内容作为key,参数的值作为值
Employee findByIdAndName(@Param("id")int id,@Param("name") String name);
//增
boolean add(Employee employee);
//改
void update(@Param("id") int id,@Param("name") String name);
insert into employee values(null,#{cellphone},#{password},#{avatar},#{name},'0');
update employee set name = #{name} where id = #{id}
EmployeeMapper mapper = sqlSession.getMapper(EmployeeMapper.class);
//5.单参
Employee byId = mapper.findById(1);
System.out.println(byId);
//6.多参
Map map = new HashMap<>();
map.put("id",1);
map.put("name","小李");
Employee byIdAndName = mapper.findByIdAndName(map);
System.out.println("map"+byIdAndName);
Employee arg = new Employee();
arg.setId(1);
arg.setName("小李");
Employee byIdAndName1 = mapper.findByIdAndName(arg);
System.out.println("arg:"+byIdAndName1);
mysql不支持多个参数单独传递,只能一个数据或者多个数据(map、entity、array、list)
Employee findByIdAndName(Map map);
Employee findByIdAndName(Employee employee);
//@Param()其实就是将参数封装为map对象,注解的内容作为key,参数的值作为值
Employee findByIdAndName(@Param("id")int id,@Param("name") String name);
实例对象与注解的方法比较好用,map一般不用