A**o
发帖数: 1550 | 1 http://fromapitosolution.blogspot.com/2008/12/criticism-of-java-persistence.html
摘要如下
"Most of applications are database-driven and need to access tables, modify
data. Although there are many questions about persistence frameworks, we
need them a lot when developing applications. Otherwise SQL codes scatters
across applications causing an ugly and unmanageable application.
Persistence frameworks build a database layer and separates concerns. Java
Persistence solutions are divided into two branch |
|
t**********s
发帖数: 930 | 2 我最近在一个家用电气上开发了个简单的计算器软件. 用户用遥控器就可以操作.
本来就是想试一下新的API, 可经理挺喜欢的. 说如果能加入persistence功能就更好了.
不确定persistence是啥意思,但不愿问经理,免得显傻.
比方说:
6+3
=
9
如果用户再按*(乘),是不是输出立刻变成:
9*
然后能接着运算?
就是上一部的结果被保存下来就叫persistence?
目前我的计算器每次计算完后再按下个输入,屏幕就清了. 上次的结果没有保留.
请问persistence是不是我理解的这个意思? |
|
S*****n
发帖数: 6055 | 3 【 以下文字转载自 NanoST 讨论区 】
发信人: Synthon (合成子·欢迎大家到化工版走一走看一看), 信区: NanoST
标 题: persistence length of MWNT
发信站: BBS 未名空间站 (Thu Dec 20 12:36:54 2007), 转信
用高分子链中的persistence length的概念研究弯曲的MWNT管子，有点意思
http://pubs.acs.org/cgi-bin/abstract.cgi/jpccck/2007/111/i51/abs/jp075062r.html
Persistence Length of Multiwalled Carbon Nanotubes with Static Bending
Heon Sang Lee,* Chang Hun Yun, Heon Mo Kim, and Cheol Jin Lee
LG Chemical Company Limited, Technology Center, Jang-Dong 84, Yusung-Gu,
Daejeon 305-343, Kore |
|
h*********e
发帖数: 6226 | 4 http://news.yahoo.com/forecasters-drought-may-persist-another-2
SAN ANTONIO (AP) — The drought that has turned Texas and parts of the
Plains into a parched moonscape of cracked earth could persist into next
year, prolonging the misery of farmers and ranchers who have endured a dry
spell that is now expected to be the state's worst since the 1950s. |
|
h**********c
发帖数: 4120 | 5 scwcd里那个persistence api的实验，我用的orcale;
当时想扩展一下，用integer型的id 做primary key，
insert 的时候用sequence+trigger,
google的话有一个oracle trigger 的段子，我在netbeans 6.8和oracle 10g express
下的sql都没做出来，
那位高人给个段子吗？
其实是想问persistence api能不能不用sequence+trigger。 |
|
h********8
发帖数: 159 | 6 我在用Hibernate 4.3.4,在createEntityManagerFactory("xxx");
已经在persistence.xml中配置了org.hibernate.jpa.
HibernatePersistenceProvider 。
用Junit调试时，还是出现了错误提示：
Mar 27, 2014 11:33:07 AM org.hibernate.ejb.HibernatePersistence
logDeprecation
WARN: HHH015016: Encountered a deprecated javax.persistence.spi.
PersistenceProvider [org.hibernate.ejb.HibernatePersistence]; use [org.
hibernate.jpa.HibernatePersistenceProvider] instead.
google了一下，发现Hibernate有这个bug,有人发了个帖子，我还是看不明白。不知道
哪位高手能帮忙解决一下。
h... 阅读全帖 |
|
r*****s
发帖数: 985 | 7 Hi,
Anybody knows that whether there is any free LDAP server that supports
Persistent Search control? I need to use JNDI's event notification
methodshttp://java.sun.com/products/jndi/tutorial/beyond/event/index.html.
It says "the LDAP server must support the Persistent Search control
(Internet-draft draft-ietf-ldapext-psearch-03.txt)." The free LDAP server
OpenLDAP with Linux doesn't support it, nor Windows Active Directory.
I only know that Netscape Directory Server v4.1 and above supports it |
|
d*****s
发帖数: 313 | 8 I know it is a complex process to determine the exact persistence length of a
given polymer. I do not need the precise number, just a rough idea what the
persistence length of my polymer is. Is there any simple calculation or
measurement that I can do? Thanks. |
|
s***e
发帖数: 911 | 9 一种测量persistence的办法是通过测量线性分子的force-extension curve实现的.
我们用这种办法测量比如dna的persistence length.
相关的理论如下:
在沿z方向外力f的作用下, worm-like-chain model给出的自由能是:
\beta E=\int_{s,0,L} (-\beta f <\hat{z},\hat{t}>+(A/2) |d \hat{t}/ds|^2)
\hat{t}是切向量, \hat{z}是z方向, \beta是1/(KT).
下面在large force下的近似下进行计算. "large force"指使得线性分子 end-to-end
distance接近contour length的力. 这时候切矢量的横向分量t_{T}是小量,而纵向
分量t_{//}可以用t_{T}展开, 最后导致\hat{t}可以完全用t_{T}展开到一级近似:
\hat{t}=t_{T} \hat{n}+(1-t_{T}^2/2) \hat{z}
\hat{n}指横向.
然后把这个近似的切矢量代回自由能, 再对t_{T}作傅立叶变 |
|
S*****n
发帖数: 6055 | 10 用高分子链中的persistence length的概念研究弯曲的MWNT管子，有点意思
http://pubs.acs.org/cgi-bin/abstract.cgi/jpccck/2007/111/i51/abs/jp075062r.html
Persistence Length of Multiwalled Carbon Nanotubes with Static Bending
Heon Sang Lee,* Chang Hun Yun, Heon Mo Kim, and Cheol Jin Lee
LG Chemical Company Limited, Technology Center, Jang-Dong 84, Yusung-Gu,
Daejeon 305-343, Korea, and School of Electrical Engineering, Korea
University, Anam-Dong, Seongbuk-Gu, Seoul 136-701, Korea
Received: June 29, 2007
In Final Form: Octob |
|
m******n
发帖数: 6327 | 11 ☆─────────────────────────────────────☆
JackFighter (我是谁？) 于 (Fri Nov 7 19:52:35 2008) 提到:
November 8, 2008
Racial Imbalance Persists at Elite Public Schools
By JAVIER C. HERNANDEZ
Asian and white eighth graders are far outpacing their black and Hispanic
peers on a test that determines admission to New York City’s elite public
high schools, perpetuating a stark racial imbalance that has swelled despite
years of efforts to make the schools more diverse.
While significant numbers of black an |
|
U**8
发帖数: 1921 | 12 Behavioral Responses to a Repetitive Visual Threat Stimulus Express a
Persistent State of Defensive Arousal in Drosophila
Current Biology
Available online 14 May 2015 |
|
T*****e
发帖数: 361 | 13 I am using EJB3 Persistence through Hibernate. My entity classes are
annotated and packed in a jar file. It works.
I have two questions.
The first one is quite simple. Can I use simple classes (other than
entities) in EJB/QL? Example:
List addresses = entityManager.createNativeQuery(
"select u.address from user as u").listResults();
The above query seems fine. But how can I use the result? I've tried:
String address = (String) addresses.get(i);
but it doesnot' work.
The second questio |
|
I*******e
发帖数: 1879 | 14 ☆─────────────────────────────────────☆
goodbug (好虫) 于 (Sun Feb 4 15:56:43 2007) 提到:
Our product never separated persistence and business layers well.
Right now we are having a new product, and I am trying to make a better
example.
Say we have a webmail, by sending a message, we need to add an entry to
message table, one entry in a message-user link table for each sender and
recipient. And then send a real email notificaiton to each recipient.
Now obviously saving data into tables are of p |
|
g*****g
发帖数: 34805 | 15 C10K没问题，即便10年前。百万用户在线的应用还是很多的。1万用户当了不过是百分
之一的冲击。
这年头没有1B在线的应用，最多100M. 你要把10M鸡蛋放进一个篮子，篮子破了有没有
足够的机器去顶住冲击，就是个很重要的问题。特别是对于persistent connection的
应用，这个冲击更为明显。
你要说做个proxy server, load balancer也罢，要套whatsApp，这是必须回答的问题
。我老
只不过出于职业的敏感，告诉你篮子破了怎么办的问题远比篮子够不够大的问题难得多。 |
|
g*****g
发帖数: 34805 | 16 这只能说明你没有实际经验。能处理10M， 再多处理1M，从容量本身看是不难。
但是你忘了，前面这10M的连接是慢慢产生的，大多数时候这些连接只有heartbeat, 没
有信息交换。
但一旦有机器当机，这1M的重新连接请求是同时到来的，伴随的是需要重新产生用户
session, 要读DB, 要计算，
会产生巨大的冲击。这个冲击远远大于10M大多idle的连接。你的机器是顶不住的。
你说的要能够处理几倍的容量同样不对，一般的做法就是跑在50％－70%，超过了动态
继续起VM。
而不是预留几倍的处理能力。这本来就是云计算的长处。
persistent connection跟stateless connection在failover设计里是有很大区别的。
前者需要更大的余量。
用100台1M和10台10M的区别是巨大的。没有真正搞过实际系统的人不会想到这些问题，
但不等于这些问题就不存在了。
我说是伪命题，就是因为世界上100M 在线的系统屈指可数，而且据我所知没有一个是
用10台机器的，几百个上千个VM才是惯例。将来如果有1000M的系统，同样会倾向于多
起VM,
而不是多压榨单机性能。篮... 阅读全帖 |
|
g*****g
发帖数: 34805 | 17 C10K没问题，即便10年前。百万用户在线的应用还是很多的。1万用户当了不过是百分
之一的冲击。
这年头没有1B在线的应用，最多100M. 你要把10M鸡蛋放进一个篮子，篮子破了有没有
足够的机器去顶住冲击，就是个很重要的问题。特别是对于persistent connection的
应用，这个冲击更为明显。
你要说做个proxy server, load balancer也罢，要套whatsApp，这是必须回答的问题
。我老
只不过出于职业的敏感，告诉你篮子破了怎么办的问题远比篮子够不够大的问题难得多。 |
|
g*****g
发帖数: 34805 | 18 这只能说明你没有实际经验。能处理10M， 再多处理1M，从容量本身看是不难。
但是你忘了，前面这10M的连接是慢慢产生的，大多数时候这些连接只有heartbeat, 没
有信息交换。
但一旦有机器当机，这1M的重新连接请求是同时到来的，伴随的是需要重新产生用户
session, 要读DB, 要计算，
会产生巨大的冲击。这个冲击远远大于10M大多idle的连接。你的机器是顶不住的。
你说的要能够处理几倍的容量同样不对，一般的做法就是跑在50％－70%，超过了动态
继续起VM。
而不是预留几倍的处理能力。这本来就是云计算的长处。
persistent connection跟stateless connection在failover设计里是有很大区别的。
前者需要更大的余量。
用100台1M和10台10M的区别是巨大的。没有真正搞过实际系统的人不会想到这些问题，
但不等于这些问题就不存在了。
我说是伪命题，就是因为世界上100M 在线的系统屈指可数，而且据我所知没有一个是
用10台机器的，几百个上千个VM才是惯例。将来如果有1000M的系统，同样会倾向于多
起VM,
而不是多压榨单机性能。篮... 阅读全帖 |
|
U**8
发帖数: 1921 | 19 Behavioral Responses to a Repetitive Visual Threat Stimulus Express a
Persistent State of Defensive Arousal in Drosophila
Current Biology
Available online 14 May 2015 |
|
f****o
发帖数: 4067 | 20
# begin build properties # autogenerated by buildinfo.sh ro.build.id=KOT49I.
LS740ZV6 ro.build.display.id=KOT49I.LS740ZV6 ro.build.version.incremental=
LS740ZV6.1440117223 ro.build.version.sdk=19 ro.build.version.codename=REL ro
.build.version.release=4.4.2 ro.build.date=Fri Aug 21 09:36:06 KST 2015 ro.
build.date.utc=1440117366 ro.build.type=user ro.build.user=jenkins ro.build.
host=LGEACI5R6 ro.build.tags=release-keys ro.product.model=LGLS740 ro.
product.brand=lge ro.product.name=x5_spr_us ro... 阅读全帖 |
|
z******8
发帖数: 844 | 21 ☆─────────────────────────────────────☆
medwater (小麦) 于 (Mon Mar 17 07:06:34 2014, 美东) 提到:
筒子们，喷油们，鸡冻银心的时候就要来临了！喝了鸡汤、吃了鸡血、啃了鸡脖的您，
准备好了吗？LOL。各位看官，有钱的捧个钱场，有人的捧个人场，小麦在这向您作揖
了！
先预祝参加match的同学都能心想事成，和自己心仪的她情定终生! 也再次恭喜
prematch的同学！
同时，真诚恭请所有参加match的同学能在麦地里和大家分享自己的喜悦和Credentials
，以供后来的麦苗提供参考。也可以把结果发给现任版务、我、蝎子或者能帮你张贴的
熟识ID，代您登出。
请参照以下模板（有位筒子已经有个很好的想法，谢谢）：
－－－－－－－
Years Post Graduation:
USMLE scores:
Visa status:
Any advanced degrees:
Clinical experience:
Programs applied:
Interview No.:
LoR source:
... 阅读全帖 |
|
J*********l
发帖数: 1185 | 22 连接有问题。
Flexible bronchoscopy as a valuable tool in the evaluation of persistent
wheezing in children.
Erkan Cakir, Refika Hamutcu Ersu, Zeynep Seda Uyan, Sedat Oktem, Bulent
Karadag, Okan Yapar, Ozge Pamukcu, Fazilet Karakoc, Elif Dagli
Division of Pediatric Pulmonology, Marmara University, Istanbul, Turkey.
International journal of pediatric otorhinolaryngology (impact factor: 0.85)
. 10/2009; 73(12):1666-8. DOI:10.1016/j.ijporl.2009.08.016
Source: PubMed
ABSTRACT Persistent wheezing is a commo... 阅读全帖 |
|
z*******3
发帖数: 13709 | 23 以后会剥离出ejb
Enterprise JavaBeans
The EJB 3.0 specification (itself part of the Java EE 5 platform) included a
definition of the Java Persistence API. However, end-users do not need an
EJB container or a Java EE application server in order to run applications
that use this persistence API.[1] Future versions of the Java Persistence
API will be defined in a separate JSR and specification rather than in the
EJB JSR/specification.
The Java Persistence API replaces the persistence solution of EJB 2.0 C... 阅读全帖 |
|
P********l
发帖数: 452 | 24 １．好牛逼．
２．不便宜．
３．很怪异．
不会丢的内存数据库：Auto-Commit Memory
But, what if an application could designate a certain area within its memory
space as persistent, and know that data in this area would maintain its
state across system reboots? This application would no longer have the
burden of following the multi-step block I/O pathway to persist that data.
It would no longer need smaller transactions to be packaged into 4k blocks
for storage. It would just place selected data meant for persistence in this
de... 阅读全帖 |
|
发帖数: 1 | 25 ddPCR 没有问题的，放心吧，只有假阳性，没有假阴性
Digital PCR as a tool to measure HIV persistence
Although antiretroviral therapy is able to suppress HIV replication in
infected patients, the virus persists and rebounds when treatment is stopped
. In order to find a cure that can eradicate the latent reservoir, one must
be able to quantify the persisting virus. Traditionally, HIV persistence
studies have used real-time PCR (qPCR) to measure the viral reservoir
represented by HIV DNA and RNA. Most recently, digital P... 阅读全帖 |
|
G******i
发帖数: 5226 | 26 ☆─────────────────────────────────────☆
lanmao (懒猫) 于 (Sat Jul 9 11:29:24 2011, 美东) 提到:
（坑已经够大了，只管挖不管填不道德，俺自个合集了。）
看了芙蓉的减肥照片和凤姐的励志围脖，也想来跟个励志潮流。满版上都是google
amazon facebook，搞得不是编程熟手不会脑筋急转弯就没好工作似的。 俺来贴个BSO
的Java面经吧，来鼓励一下正在奋斗着的童鞋们。认识俺的都不要说啊，俺那么低调~~~
个人背景：人工智能方向的，学校算top 50吧，9月答辩，读了整整八年的老博士马上
就要新鲜出炉啦！
先低调的说一下amazon经历。amazon给俺发信三四次，要求俺去面试，没理。HR打电话
过来说为啥不理，俺说你们招聘职位太entry level，没兴趣。HR说那给你找个高层次
点的职位。过两天打电话来，说有个高级程序员的活，能不能给我们的hiring manager
一个向你展示我们项目产品的机会。俺心想，说得好听，还不是又要问那种脑筋急转弯
问题，反正答不出，没必要耽误时间。于是很彪... 阅读全帖 |
|
y***v
发帖数: 270 | 27 你们看看： 比较长，
转一篇文章。让事实为肖传国说话
转自：虹桥科教论坛 http://www.rainbowplan.org/bbs/topic.php?topic=114563&select=&forum=1
有人在散仙谷转了一篇文章。应该把这篇文章广为转发。让当局和国内不明真相的人民
都知道肖传国的医学探索的价值。方舟子夹私打假必然会被钉在科学的耻辱柱上。
“肖氏反射弧”真相解析
肖传国教授在世界上第一个提出并证实 “人工建立体神经-内脏神经反射弧” 用于治
疗各种脊髓损伤导致的排尿障碍。这一发现在肖传国与方舟子之间挑起了一场科学与反
科学长达五年的论战。为帮助公众了解这场论战的事实真相，本文首先从学术角度根据
科学文献和科学事实对“肖氏反射弧”作一番解析。
反射是神经支配机体生理机能的基本方式。反射弧一般由感受器，传入神经，反射中枢
，传出神经和效应器组成。正常的排尿反射由位于脑干和大脑皮层的高级排尿中枢控制
达骶髓的排尿反射初级中枢完成。膀胱充盈时，膀胱壁的牵张感受器受到刺激而兴奋。
冲动传入高级中枢产生排尿欲。中枢经过判断认为可以排尿，于是发出神经冲动沿下行
传导束到脊髓初... 阅读全帖 |
|
n****1
发帖数: 1136 | 28 版上无数大佬声称OOP比FP更加符合人类的思维方式,俺个土鳖来唱个反调.
所有的程序,不管采用什么模式,架构, 其最终目的都是IO+persistence, 70%以上的应
用仅仅是CRUD外加个包装而已. 大多数应用的persistence是tabular database, 这包
括mysql这类ACID数据库, 也包括big table/cassandra这类的分布式数据库. 当然也有
OO database, 但普及率/接收度/性能都不如前者.
我们不妨回想在电脑诞生之前, 人类对一个复杂问题是如何建模与解决的.复杂问题千
奇百怪,比如生物学家要对物种进行门纲目科属种的划分, 这种划分能够体现各物种之
间的异同程度. 再举个例子,统计学家要做个人口普查,那就要建立个大表格,每一行都
对应一个人, 行中记录包括生日/性别/籍贯等等各种信息,这样我们从一个表里就可以
得到籍贯分布,人口年龄结构,地域与受教育程度的关联等等.
事实上在OOP普及以前,人类对事物种类的划分是有限的, 因为现实中存在的东西就那么
几样, 人们也不大需要过研究什么抽象物体. 可OOP发明后就不一样了, 程序... 阅读全帖 |
|
z****e
发帖数: 54598 | 29
rdd
stream就是那种连续的，不间断过来的数据
batch就是那种已知边界的数据
spark的streaming只是mincro batch
本质上还是bacth，不是streaming
streaming要求过来一个就处理一个，而且一次就处理一个
这种就是真streaming，如果达不到这种要求，就是伪streaming
microbatch顾名思义，不是这种搞法
streaming的好处显而易见，时效性强，可以很快作出反应
但是坏处也很明显，需要资源比较多
而且从长时间上看，比如处理chunk，总体算下来
还是batch用时比较节省
其实streaming我个人认为并不适合用来做persistance的处理
尤其是file system, db上的数据，我觉得用batch就足够了
streaming用在对付需要短时间处理并反馈的数据
主要是用来处理web上过来的数据，比如video这些
还有tweets，还比如用一个udp socket直接监听一个port就好了
这些用streaming api就非常合理，可以增强客户体验
他们还有第三种api，就是table api，这个... 阅读全帖 |
|
f********x
发帖数: 99 | 30 The world beyond batch: Streaming 101: A high-level tour of modern data-
processing concept
http://radar.oreilly.com/2015/08/the-world-beyond-batch-streami
by Tyler Akidau August 5, 2015
Editor’s note: This is the first post in a two-part series about the
evolution of data processing, with a focus on streaming systems, unbounded
data sets, and the future of big data.
Streaming data processing is a big deal in big data these days, and for good
reasons. Amongst them:
Businesses crave ever more tim... 阅读全帖 |
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e****0
发帖数: 678 | 31 • leukemia
ALL AML CLL
child adult elderly
BM lymphoblasts 25%myeloblasts
lab Lymphocyte 5000, mature-appearing cells
• Osgood-schlatters disease
Adolescent male athletes
Traction apophysitis—quadriceps tendon put the traction on the
apophysis of the tibial tubercle where patellar tendon inserts.
A firm mass =heterotopic bone formation
Pain can be reproduced by extending the kne... 阅读全帖 |
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b********n
发帖数: 38600 | 32 将军们给看看，这是什么：
ActiveX/COM Issue JavaPlugin - {CAF-Shootingcomputerattackblanks}HKCR\
JavaPlugin
ActiveX/COM Issue JavaPlugin.180_25 - {CA-blank} HKCR\JavaPlugin.180_25
ActiveX/COM Issue InProcServer32\C:\Program Files (x86)\Java\jre1.8.0_25\bin
\wsdetect.Kosherdill HKCR\CLSID\{blank}
ActiveX/COM Issue InProcServer32\C:\Program Files (x86)\Google\Update\1.3.24
.7\psmachine.dll HKCR\CLSID\{Blank}
ActiveX/COM Issue InProcServer32\C:\Program Files (x86)\Google\Update\-.
00001.3.24.7\psmachine_64.dll ... 阅读全帖 |
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g*****n
发帖数: 357 | 33 普通人如何实现财务自由
How to Find The Job You Love - Road to Financial Freedom -017
Hey, it’s Dr. Liu here with Better LIFE Research TIPS. In this video, I
will discuss how to find a job we love and how to get financial freedom
through our own efforts. It is really a big topic deserve a lot of time, but
I will try to make it simple and clear.
When talking about what to do in your life, there may be 4 choices. The
first is, things you love. If you do what you love, you will be happy. The
second is, things ... 阅读全帖 |
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W******e
发帖数: 3319 | 34 1. Introduction
My interest in studying creativity was inspired by the frustrations that I
felt as a student, then as a professor. I wanted to know how I could
encourage creativity in myself, my students, and my colleagues.
Politicians, industrial managers, academic administrators, and other leaders
often say that innovation is critical to the future of civilization, our
country, their company, etc. But in practice, these same people often act as
if innovation is an evil that must be suppressed,... 阅读全帖 |
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k****r
发帖数: 851 | 35 被tag成天才对发展persistence啥的是极为不利的.大家不都觉得天才就是做什么都不
费吹灰之力吗.persistence不就是做好久都做不好还不停的努力吗.说一个人
persistent就否定了他天才. 小孩子往往喜欢天才的glamor,不喜欢被夸persistent.
其实,天才做真正有点难度事情也是会很费劲的.考试考的好考的快只是因为考试太简单
了.几个小时就能作出答案的东西,怎么可能难?
forty |
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p**********u
发帖数: 15479 | 36 Hello! Thank you, thank you all so much. It is great to be back in San
Francisco, a place that has a big big spot in my heart and to be able to
speak with all of you this afternoon.
Please be seated and you can jump up and down its been a wonderful but long
day I hear.
I want to thank Anne not just for her kind introduction but for exemplifying
the kind of creative entrepreneurial leadership that she has demonstrated
and that so many of you are also part of. I want to thank Alexandr Roddy for
he... 阅读全帖 |
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w**********k
发帖数: 1135 | 37 An entity bean can implement data persistence in one of two ways:
bean-managed or container-managed. In the case of bean-managed
persistence, the implementor of an entity bean stores and retrieves the
information managed by the bean by means of direct database calls. For
these, the bean can use either JDBC or JSQL. The one tradeoff of this
approach is that it makes it harder to adapt bean managed persistence to
alternate data sources.
In the case of container-managed persistence, the container p |
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i****e
发帖数: 913 | 38 Spring's use of unchecked data access exceptions is consistent with that of
many - probably most - successful persistence frameworks. (Indeed, it was
partly inspired by JDO.) JDBC is one of the few data access APIs to use
checked exceptions. TopLink and JDO, for example, use unchecked exceptions
exclusively. Hibernate switched from checked to unchecked exceptions in
version 3.
这是Rod讲解Spring JDBC的原话
http://www.theserverside.com/news/1364527/Introduction-to-the-S
大体意思是:
By wrapping JDBC check exce... 阅读全帖 |
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z*******3
发帖数: 13709 | 39 business logic理论上是无状态的
换句话说，business这一层做的事情
一不碰web，二不碰persistence
只处理逻辑，最理想的business bean理论上都应该是无状态的
我们举个例子
比如有一个阿三，从web上发了一个request过来
那么如何handle这个request是web层的事
最基础的就是servlet了，然后是spring mvc，或者是struts，或者jsf etc.
然后这一层的这些东东把request里面的变量给取出来
包装成一个pojo，就是一个实体，set/get这些东西
然后把这个pojo留住，这是第一步
这一层是web层，spring里面叫做controller
或者是struts里面的action这些东西，这些都是controller
mvc里面其它的m就是刚才做的那个pojo
v就是jsp这些东西
然后第二步，用hibernate，ibatis等jpa实现包装db
封装所有的db操作，这是persistence层
一般来说你会写出一堆的dao类去封装各种db的操作
比如增删改查等等
spring里面叫做reposito... 阅读全帖 |
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z****e
发帖数: 54598 | 40 你这么理解倒也不错，但是可以更贴切一点
j2ee是engineering的东西，所以很多概念就都来自engineering
来自飞机制造以及建筑学等领域
用建筑学来比喻更好一点
j2ee的一成套软件就是帮你把framework给搭建好
你看建房子就知道了，一般都是先打起一个框架来
这个框架里面什么都没有，连墙壁都是空的，完全就是一个横的和竖的钢筋的交叉
但是光有框架是不能住人的，离真正的建筑还很远
等这个框架搭建好了之后，再把墙壁什么给填进去
core java的工作就是搭建这些框架
而j2ee的工作就是填入这些还不存在的部分也就是组件
这两份工作可以分开做，由不同的人和不同的group完成
比如框架一般由red hat，ibm这些公司完成，组件则由银行的it division等完成
当然这都是建房子，都是钢筋混凝土，所以从某种意义上说，这两批人都毕业自同一所
大学
以及同一个专业，他们之前很有可能是同学，所以这两者之间的界限很模糊
另外还有一些公司不太一样，这些公司不用别人的框架，大多数时候都自己造
从框架到组件都是自行完成，当然这样做有好处，好处就是可以在一定程度上优化代码
毕竟都... 阅读全帖 |
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e****0
发帖数: 678 | 41 • Exaggerated deep tendon reflexes can be seen in lock in syndrome.
• Non bleeding varices are managed with nonselective beta-
adrenergic antagonists, such as propranolol.
• Sclerotherapy, endoscopic band ligation, and surgery are
indicated after a patient has a first episode of variceal bleeding.
• TIPS is a last resort in variceal bleeding unresponsive to
medical and endoscopic intervention.
• Ischemic colitis
CT—thickening of eth bowel ... 阅读全帖 |
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n***w
发帖数: 2405 | 42 Persistent Hyperplastic Primary Vitreous (PHPV)
Definition: PHPV is a congenital condition with persistent hyaloid
vasculature and mesenchymal tissue from the embryonic primary vitreous in a
microphthalmic eye. It is often seen in combination with other syndromes.
The syndrome has been renamed recently as persistent fetal vasculature.
Incidence/Prevalence: Rare. About 50 cases were seen in a busy pediatric
referral surgery practice over 10 years (Ref 2).
Etiology: Described by Reese in 1949, PHP... 阅读全帖 |
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w****j
发帖数: 5581 | 43 罗素的西方哲学史也不是什么难找到书。我就贴一下好了：
... Against the more insane forms of subjectivism in modern times there have
been various reactions. First, a half-way compromise philosophy, the
doctrine of liberalism, which attempted to assign the respective spheres of
government and the individual. This begins, in its modern form, with Locke,
who is as much opposed to ‘enthusiasm’-the individualism of the
Anabaptists-as to absolute authority and blind subservience to tradition. A
more thorough-going revolt leads to... 阅读全帖 |
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s***q
发帖数: 10585 | 45 【 以下文字转载自 USANews 讨论区 】
发信人: siliq (From 外F to mongrels), 信区: USANews
标 题: (原创) 说说霉国捅鸡局是如何在CPI上做假的
发信站: BBS 未名空间站 (Fri Oct 5 19:27:17 2012, 美东)
可以说，霉国的捅鸡局在操纵数据上，比起天朝的同行们更加无耻，无底线
看看捅鸡局是如何在数字上做假的........今天咱们先谈谈CPI
1，通过排除食品和汽油价格，实现人为压低CPI的效果
CPI数据在发布时，分为两种，即Headline CPI和Core CPI。
请注意，前者和后者的唯一区别在于，后者排除了食品和能源的价格。
霉国捅鸡局对此的解释是“食品和能源价格短期内波动太大，因而Core CPI不计算在内”
这里是WIKI上面给出的原文：
This measure of core inflation systematically excludes
food and energy prices because, historically, they have
been highly volat... 阅读全帖 |
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h******y
发帖数: 1374 | 46 http://www.nytimes.com/2013/01/31/technology/chinese-hackers-in
Hackers in China Attacked The Times for Last 4 Months
By NICOLE PERLROTH
Published: January 30, 2013
SAN FRANCISCO — For the last four months, Chinese hackers have persistently
attacked The New York Times, infiltrating its computer systems and getting
passwords for its reporters and other employees.
Enlarge This Image
The New York Times published an article in October about the wealth of the
family of China's prime minister, Wen Jia... 阅读全帖 |
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a***k
发帖数: 1038 | 47 【 以下文字转载自 paladin 讨论区 】
发信人: atack (小军号), 信区: paladin
标 题: 红死病 by 杰克.伦敦
发信站: BBS 未名空间站 (Sat Oct 11 07:40:15 2014, 美东)
I
The way led along upon what had once been the embankment of a railroad. But
no train had run upon it for many years. The forest on either side swelled
up the slopes of the embankment and crested across it in a green wave of
trees and bushes. The trail was as narrow as a man's body, and was no more
than a wild-animal runway.
Occasionally, a piece of rusty iron, showing through ... 阅读全帖 |
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