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隨筆 - 173
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book

Apache 重寫規(guī)則的常見應(yīng)用 (rewrite)
http://lamp.linux.gov.cn/Apache/ApacheMenu/rewrite/rewrite_guide.html http://www.eygle.com/digest/2005/09/apache_oeoeooaeuooa_rewrite.html http://bbs.phpres.com/archiver/tid-2093.html
c3p0 - JDBC3 Connection and Statement Pooling
十八春
林彪的這一生
林氏三兄弟
講解數(shù)據(jù)庫調(diào)優(yōu)與程序員相關(guān)的幾個方面

tools

經(jīng)典強(qiáng)大的服務(wù)器軟件Apache
linux的命令詳解2
spring 、 struts 整合
在eclipse上配置svn
或http://dev2dev.bea.com.cn/techdoc/20060620822.html
如何在Windows Console下使用命令svn
通過 JAX-RPC 來處理異常
配置適用于正式使用環(huán)境下的Tomcat Web服務(wù)器雙向SSL認(rèn)證

為什么在hibernate中用list影射one-to-many時，在查詢數(shù)據(jù)時，經(jīng)常有null值

Learned a little this weekend - Bag vs List in Hibernate. I was troubled since i really wanted to have a Java ArrayList in my object so i could index in my jsp and iterate over the list in an update form. Using a Hibernate Set left me unable to index. A Hibernate List left the Java ArrayList populated using the primary key - if the keys were 0,1,2,... that would have been ok. But i only needed a few items from the database in my ArrayList and since the Hibernate List maintains the position of the object in the ArrayList equal to the position in the database the technique was leaving holes in my ArrayList of nulls. Of course this was not what i wanted. Now this may be explained in the documentation but after reading it twice i did not fully understand the Hibernate List. Over the weekend i read the book Hibernate in Action and discovered the Hibernate Bag and it solved my problem. I can use a Java ArrayList that is loaded simply by adding new objects to the beginning of the ArrayList.

posted on 2007-04-05 16:50 lqx 閱讀(3067) 評論(1) 編輯收藏

# re: 為什么在hibernate中用list影射one-to-many時，在查詢數(shù)據(jù)時，經(jīng)常有null值 2015-06-15 18:53 游客