各位大牛 刚开始学Mybatis 小弟我如何看见有的人配置 resultMap里用实体类 有的人用java.util.HashMap 配置有啥诀窍
各位大牛 刚开始学Mybatis 我怎么看见有的人配置 resultMap里用实体类 有的人用java.util.HashMap 配置有啥诀窍啊
各位大牛 刚开始学Mybatis 我怎么看见有的人配置 resultMap里用实体类 有的人用java.util.HashMap 配置有啥诀窍啊
在<select 标签里 有的人配置resultType="java.util.HashMap"
有的人配置 resultMap 我都搞糊涂了 谁能给我讲讲吗 有统一的标准吗
------解决思路----------------------
以下为个人理解
你说的两种方式一种是配置好实体类、那得建立在简单的SQL语句 如select * from table
hashmap就不用考虑返回的数据对应的类了 比如下方的SQL语句我就用hashmap、
其实是我比较懒、勿喷
select
B.id as blog_id,
B.title as blog_title,
B.author_id as blog_author_id,
A.id as author_id,
A.username as author_username,
A.password as author_password,
A.email as author_email,
A.bio as author_bio,
A.favourite_section as author_favourite_section,
P.id as post_id,
P.blog_id as post_blog_id,
P.author_id as post_author_id,
P.created_on as post_created_on,
P.section as post_section,
P.subject as post_subject,
P.draft as draft,
P.body as post_body,
C.id as comment_id,
C.post_id as comment_post_id,
C.name as comment_name,
C.comment as comment_text,
T.id as tag_id,
T.name as tag_name
from Blog B
left outer join Author A on B.author_id = A.id
left outer join Post P on B.id = P.blog_id
left outer join Comment C on P.id = C.post_id
left outer join Post_Tag PT on PT.post_id = P.id
left outer join Tag T on PT.tag_id = T.id
where B.id = #{id}
------解决思路----------------------
以下为个人理解
你说的两种方式一种是配置好实体类、那得建立在简单的SQL语句 如select * from table
hashmap就不用考虑返回的数据对应的类了 比如下方的SQL语句我就用hashmap、其实是我比较懒、勿喷
select
B.id as blog_id,
B.title as blog_title,
B.author_id as blog_author_id,
A.id as author_id,
A.username as author_username,
A.password as author_password,
A.email as author_email,
A.bio as author_bio,
A.favourite_section as author_favourite_section,
P.id as post_id,
P.blog_id as post_blog_id,
P.author_id as post_author_id,
P.created_on as post_created_on,
P.section as post_section,
P.subject as post_subject,
P.draft as draft,
P.body as post_body,
C.id as comment_id,
C.post_id as comment_post_id,
C.name as comment_name,
C.comment as comment_text,
T.id as tag_id,
T.name as tag_name
from Blog B
left outer join Author A on B.author_id = A.id
left outer join Post P on B.id = P.blog_id
left outer join Comment C on P.id = C.post_id
left outer join Post_Tag PT on PT.post_id = P.id
left outer join Tag T on PT.tag_id = T.id
where B.id = #{id}
------解决思路----------------------
ResultType可以是一个对象，或一个字段。
在返回一个list<user>时，你只要在ResultType中写下xxx.xxxx.user就可以。。。
ResultMap 一般多表联查时的返回结果，因为用一个对象无法装结果了，所以就用Map，这个map你可以在当前的xml中配制，也可以用util包下的map。
各位大牛 刚开始学Mybatis 我怎么看见有的人配置 resultMap里用实体类 有的人用java.util.HashMap 配置有啥诀窍啊
在<select 标签里 有的人配置resultType="java.util.HashMap"
有的人配置 resultMap 我都搞糊涂了 谁能给我讲讲吗 有统一的标准吗
------解决思路----------------------
以下为个人理解
你说的两种方式一种是配置好实体类、那得建立在简单的SQL语句 如select * from table
hashmap就不用考虑返回的数据对应的类了 比如下方的SQL语句我就用hashmap、
select
B.id as blog_id,
B.title as blog_title,
B.author_id as blog_author_id,
A.id as author_id,
A.username as author_username,
A.password as author_password,
A.email as author_email,
A.bio as author_bio,
A.favourite_section as author_favourite_section,
P.id as post_id,
P.blog_id as post_blog_id,
P.author_id as post_author_id,
P.created_on as post_created_on,
P.section as post_section,
P.subject as post_subject,
P.draft as draft,
P.body as post_body,
C.id as comment_id,
C.post_id as comment_post_id,
C.name as comment_name,
C.comment as comment_text,
T.id as tag_id,
T.name as tag_name
from Blog B
left outer join Author A on B.author_id = A.id
left outer join Post P on B.id = P.blog_id
left outer join Comment C on P.id = C.post_id
left outer join Post_Tag PT on PT.post_id = P.id
left outer join Tag T on PT.tag_id = T.id
where B.id = #{id}
------解决思路----------------------
以下为个人理解
你说的两种方式一种是配置好实体类、那得建立在简单的SQL语句 如select * from table
hashmap就不用考虑返回的数据对应的类了 比如下方的SQL语句我就用hashmap、
select
B.id as blog_id,
B.title as blog_title,
B.author_id as blog_author_id,
A.id as author_id,
A.username as author_username,
A.password as author_password,
A.email as author_email,
A.bio as author_bio,
A.favourite_section as author_favourite_section,
P.id as post_id,
P.blog_id as post_blog_id,
P.author_id as post_author_id,
P.created_on as post_created_on,
P.section as post_section,
P.subject as post_subject,
P.draft as draft,
P.body as post_body,
C.id as comment_id,
C.post_id as comment_post_id,
C.name as comment_name,
C.comment as comment_text,
T.id as tag_id,
T.name as tag_name
from Blog B
left outer join Author A on B.author_id = A.id
left outer join Post P on B.id = P.blog_id
left outer join Comment C on P.id = C.post_id
left outer join Post_Tag PT on PT.post_id = P.id
left outer join Tag T on PT.tag_id = T.id
where B.id = #{id}
------解决思路----------------------
ResultType可以是一个对象，或一个字段。
在返回一个list<user>时，你只要在ResultType中写下xxx.xxxx.user就可以。。。
ResultMap 一般多表联查时的返回结果，因为用一个对象无法装结果了，所以就用Map，这个map你可以在当前的xml中配制，也可以用util包下的map。