笔记

2、使用Mybatis注解开发视频列表增删改查
   讲解:使用Mybatis3.x注解方式增删改查实操, 控制台打印sql语句

       1、控制台打印sql语句
           #增加打印sql语句，一般用于本地开发测试
           mybatis.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl

2、增加mapper代码
                   @Select(“select * from video”)
               // @Results({
               // @Result(column = “cover_img”,property =
                   “coverImg”),
               // @Result(column = “create_time”,property =
                   “createTime”)
               // })
               List<Video> findAll();
               @Select(“SELECT * FROM video WHERE id = #{id}”)
               Video findById(int id);
               @Update(“UPDATE video SET title=#{title} WHERE id =#{id}”)
              int update(Video Video);

@Delete(“DELETE FROM video WHERE id =#{id}”)
int delete(int id);

@Insert(“INSERT INTO `video` ( `title`, `summary`, ” +
           “`cover_img`, `view_num`, `price`, `create_time`,” +
               ” `online`, `point`)” +
           “VALUES” +
           “(#{title}, #{summary}, #{coverImg}, #{viewNum}, #{price},#{createTime}” +
           “,#{online},#{point});”)
           @Options(useGeneratedKeys=true, keyProperty=”id”, keyColumn=”id”)
           int save(Video video);

3、保存保存
技巧：保存对象，获取数据库自增id
@Options(useGeneratedKeys=true, keyProperty=”id”, keyColumn=”id”)

4、技巧：
          数据库字段下划线和Java实体类映射
         # mybatis 下划线转驼峰配置,两者都可以
           #mybatis.configuration.mapUnderscoreToCamelCase=true
           mybatis.configuration.map-underscore-to-camel-case=true