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该话题已被移动 - floater , 2004-06-16 01:58
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作者

Re:J2EE交流贴 [Re:Jove]

hitaco

发贴: 432
积分: 31

于 2004-06-16 23:17

page 4, User-->VO
I guess in some situations User may represent Business object/Domain object, for example, in hibernate architecheture, object can be detached, we do not need VO just holding data for business object.

page 6: ResultSet/Paging/ResultSet::absolute()
Some JDBC driver will not skip the data.
Suppose we have 10000 records in the query result and we are interested only in the 9999th row.
rs.abolute(9999) is not good concerning the performance, it will not be more efficient than looping the resultset from the very begining, which will cost much more time than rownum approach. (BTW: I have tested this in oracle driver)

page 9: query by inner class, anonymous inner class are good when used as strategy objects, but most developers will be confused with the syntax,
my opinion about inner class is: do not put too much code in the inner class, in some situations, we can create a helper method which will be invoked from the inner class.

String[] getAllUsername() {
final ArrayList list = new ArrayList();

return (String[]) jdbcTemplate.query("select name from user", new RowCallbackHandler() {
  public void processRow(ResultSet rs) throws SQLException {
   list.add(rs.getString("name"));
  }
})

return ......
}

about RuntimeException/Checked Exception:
I have seem many applications just try/Catch SQLException in DAO and wrap as app-specific exception, rethrown it, and let session bean layer to catch it and call SessionContext::setRollbackOnly(), it's not good, I prefer touse RuntimeException and let EJB Container automatically rollback the transaction, BTW, I do not know how hibernate deal with transaction when RuntimeException occurs.

话题树型展开

人气	标题	作者	字数	发贴时间
25017	[精华] J2EE交流贴	Jove	129	2004-06-15 16:11
21283	Re:J2EE交流贴	jfml	15	2004-06-15 16:16
21148	Re:J2EE交流贴	floater	3646	2004-06-16 22:39
21146	Re:J2EE交流贴	hitaco	1731	2004-06-16 23:17
21275	Re:J2EE交流贴	jigsaw	573	2004-06-17 09:36
21142	Re:J2EE交流贴	hitaco	1161	2004-06-17 10:13
21202	Re:J2EE交流贴	jigsaw	335	2004-06-17 09:44
21203	Re:J2EE交流贴	floater	322	2004-06-17 10:00
21195	Re:J2EE交流贴	floater	69	2004-06-17 10:13
21187	Re:J2EE交流贴	chenyajun5	21	2004-06-17 11:16
21172	Re:J2EE交流贴	zyzhang	1828	2004-06-17 22:04
21153	Re:J2EE交流贴	floater	460	2004-06-18 09:22
21249	Re:J2EE交流贴	Jove	617	2004-06-18 10:24
21093	Re:J2EE交流贴	floater	1158	2004-06-18 13:50
21152	Re:J2EE交流贴	Jove	308	2004-06-18 14:48
21225	Re:J2EE交流贴	nothing	4	2004-06-15 16:34
21100	Re:J2EE交流贴	floater	431	2004-06-18 21:32
20997	Re:J2EE交流贴	zyzhang	3887	2004-06-22 01:48
22619	Re:J2EE交流贴	zhbk	10	2004-07-30 14:58
21059	Re:J2EE交流贴	winconcom	23	2004-09-09 11:45
21434	Re:J2EE交流贴	jigsaw	55	2004-06-15 16:57
21376	Re:J2EE交流贴	wes109	0	2004-06-15 17:21
21326	Re:J2EE交流贴	wes109	25	2004-06-15 17:34
21325	Re:J2EE交流贴	zyzhang	412	2004-06-15 18:14
21982	Re:J2EE交流贴	floater	3201	2004-06-16 03:05
21220	Re:J2EE交流贴	jigsaw	4037	2004-06-16 13:45
21094	Re:J2EE交流贴	zyzhang	5937	2004-06-16 19:44
21303	Re:J2EE交流贴	Jove	357	2004-06-16 14:31
21220	Re:J2EE交流贴	Jove	136	2004-06-17 10:04
21241	Re:J2EE交流贴(2nd rar)	Jove	58	2004-06-17 10:06

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