可以在工具类创建时实现自动提交事务
public static SqlSession getSqlSession(){
return sqlSessionFactory.openSession(true);
//改成 true 可自动提交事务 ，不需要commit
}
编写接口，增加注解
public interface UserMapper {
@Select("Select * from user")
List<User> getUsers();
@Select("Select *from user where id=#{id}")
User getUsersByID(@Param("id") int id);//方法存在多个参数,所有的参数前面必须加上 @Param("id")注解
@Delete("delete from user where id = #{id}")
int deleteUser(@Param("id") int id);
@Update("update user set name =#{name},pwd=#{pwd} where id =#{id}")
int updateUser(User user);
}
测试类
public class Text01 {
@Test
public void getUsers(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
List<User> users= mapper.getUsers();
for (User user : users){
System.out.println(user);
}
sqlSession.close();
}
@Test
public void getUsersByID(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
User usersByID = mapper.getUsersByID(4);
System.out.println(usersByID);
sqlSession.close();
}
@Test
public void updateUser(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
mapper.updateUser(new User(1,"哈dsasa哈","888888"));
sqlSession.close();
}
@Test
public void deleteUser(){
SqlSession sqlSession = MybatisUtils.getSqlSession();
UserMapper mapper = sqlSession.getMapper(UserMapper.class);
mapper.deleteUser(3);
sqlSession.close();
}
}
注意！！！
必须将接口绑定注册到mapper核心配置文件中
--------------------------------------------
关于Param（）注解
1：基本类型的参数或者String类型，需要加上
2：引用类型不用加
3：如果只有一个基本类型的话，可以忽略，但建议加上
4：我们在sql中引用的就是 @Param("xxx")中设定的属性名