mybatis增删改查

        //加载基本配置文件（法一）
      InputStream is = Resources.getResourceAsStream("mybatis-config.xml");
      SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(is);
  

        //加载基本配置文件（法二）
        Reader reader = Resources.getResourceAsReader("mybatis-config.xml");
        SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(reader);

    //第三种方式：注解，sql语句放在接口里面，抽象方法的上面。如果使用这种方式，需要将存储sql语句的Mapper.xml文件删除。注解和.xml只能存在一个
   // @Select("Select * from book")
    List selectAll();

        SqlSession sqlSession = sqlSessionFactory.openSession();
        //获取接口实例
        BookMapper mapper = sqlSession.getMapper(BookMapper.class);

如：传入某个对象，或者传入某个map 

BookMapper.xml

    
        insert into book(name,author,price) values (#{name},#{author},#{price})
    

BookMapper接口

int insertOne(Book book);

测试类

     Book book = new Book("天气预报", "小王", 10);
     int num = mapper.insertOne(book);
     System.out.println("添加结果是："+num);

• 解决多参数和传入参数无法对应的问题
• 1.仅sql语句赋值用#{arg}

    
        insert into book(name,author,price) values (#{arg0},#{arg1},#{arg2})
    

• 2.仅接口抽象方法用@Param("name")  其中value = 可以省略  比较常用

    int insertOne2(@Param(value = "name")String name,
                   @Param(value = "author")String author,
                   @Param(value = "price")double price);

• 3.传递map ，类似于传递一个对象整体

BookMapper.xml  可以保持没有修改的值

    
        update book set name = #{name},
                        
                            author = #{author},
                        
                        price = #{price} where id = #{id}