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Re:JDBC revisit [Re:floater]

floater

Java Jedi

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发贴: 3233
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于 2003-09-21 11:47

Recently, Why introduced us this nice framework:
http://www.cjsdn.com/post/view?bid=21&id=48838

I took a look at the source code and gave out some comments in the above post.

In this post, let's see how to fix the problems I mentioned. Basically, we are taking a refactoring approach, the bottom line is that if the code is too long(I use the rule: every class file shouldn't go beyond 500 lines, and I haven't seen exceptions in application development).

1. The connection pool should be out, in a seperate package. What we pass into here should be just a connection because that's all it's related. In fact, the connection pool and datasource should have its own package, independent of everything else. So we pass the Connection object to the constructor.
2. Transaction handling is also connection related, so we leave that out in a seperate class.
3. The error handling is kind of wicky. It has a bunch of functions to check what the root cause is. Comm'n, I don't want to go through each call to know exactly what's wrong, just tell me what it is, I am a lazy guy. Besides, if we know the error, we won't be able to do anything in the code(with if statements). So we change it to a simple msg.
4. Continue in error handling, we really don't need subclasses to translate any specific db error code. We could, instead, use a properties file to map the error codes to messages. This saves users from programming. So we add a file name to the constructor.
5. If we take a bird view of the main class, it has a big chunk of code for SQL parameter settings. We could move them out of here. There is another big chunk of code dealing with converting from primitive typs to objects, so let's move this piece out too.
6. The SQLResult class is mixed with implemention interface with user interface, so we should seperate them too(input/output).

Having done these, we have something like this file tree:
(ignore the files with names starting with Test..., they are for testing purpose).

why edited on 2003-10-26 10:33

"Any fool can write code that a computer can understand. Good programmers write code that humans can understand."
- Martin Fowler, Refactoring - Improving the Design of Existing Code

话题树型展开

人气	标题	作者	字数	发贴时间
16697	JDBC revisit	floater	7109	2003-07-01 02:50
14908	Re:JDBC revisit	floater	2005	2003-09-21 11:47
13931	Re:JDBC revisit	floater	112	2003-09-28 04:49
17885	Re:JDBC revisit	floater	291	2003-09-28 04:54
14004	Re:JDBC revisit	floater	2176	2003-09-21 12:10
13947	Re:JDBC revisit	floater	1046	2003-09-21 12:22
14102	Re:JDBC revisit	mazalet	6	2003-09-21 12:43
14089	Re:JDBC revisit	Johnny	39	2003-09-22 09:44
13890	Re:JDBC revisit	floater	48	2003-09-22 10:03
14023	Re:JDBC revisit	Johnny	589	2003-09-24 09:40
13840	Re:JDBC revisit	floater	82	2003-09-24 10:06
13975	Re:JDBC revisit	Johnny	57	2003-09-25 10:50
13804	Re:JDBC revisit	floater	131	2003-09-25 11:15

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