OT: Conside postgreSQL! It is FREE, ansi SQL compliat, etc. etc. Bill Blackmon wrote: > Thanks - all of the DAO classes are static. I don't think that is the > immediate problem. I'm having > a concurrent list modification that occurs on a single record. Since there > are no nested select statement > in MySQL, I'm having to use a lot of list and select statements. It really > sucks.....I just have to track down > the bug and re-evaluate some other things. Quickly....:) > ----- Original Message ----- > From: "V. Cekvenich" <[EMAIL PROTECTED]> > To: <[EMAIL PROTECTED]> > Sent: Sunday, September 29, 2002 8:49 PM > Subject: JDBC Connection pool sample code; was Re: Best practices for Tomcat > and server load > > > >>A FAQ is what is good practice for JDBC connection pooling and how to >>use it with Java Beans. >> >>My Ans, with working source code: >> >>(A good practices is: a property that has a getter/setter in a bean, and >>a bean has a DAO it delegates to.) >> >>You could have a DAO with a class/static initialize that gets the data >>source/connection pool >>I do not like philosophical answers so here is a code sample, note use >>of static, hence done once to get a handle on the data source/connection >>pool: >> > > http://cvs.sourceforge.net/cgi-bin/viewcvs.cgi/basicportal/basicPortal_07/sr > c/org/commons/DAO/BasicDAOImpl.java?rev=1.1.1.1&content-type=text/vnd.viewcv > s-markup > >>It uses DBCP from Jakarta commons connection pool, but you get the point >>of how to use a static class initialize to get a handle to a data source >>so you can look up the data source once, and then just dish out > > connection. > >>Also I use rowset over resultset, which makes it very easy to close, and >>destroy, unlike resultset. (con.close,rs.close, stmnt.close in finaly, >>plus it loses data on a connection disconect) >>Rowset also does reduces need for GC generated by VO/DTO and >>collections, since a disconnected rowset has the values. I use an open >>source rowset from sourceforge called jxutil. >> >>hth, >>V. >> >>ps: Consider doing MVC, hence each layer is unit testable, such as a >>bean that delegates to DAO interface, which above also enables, as well >>as enabling you to change the implemenentation of the DAO. >> >>ps2: Answer to what is the most popular hands on training class and who >>teaches it? >>http://www.mail-archive.com/mvc-programmers%40basebeans.com/msg00242.html >> >>Also, at basicPortal.sf.net you can download for free a 350 page book a >>bit more advanced that talks about db quite a bit. >> >> >> >>Bill Blackmon wrote: >> >>>I'm getting complaints from my host about excessive CPU usage in my web >> > app. > >>>I'm unable to use >>>connection pooling in the servers environment so I'm using a new >> > connection > >>>for each DB call (and >>>there are quite a few). The connections are promptly closed afterwards. >> > Is > >>>it a better idea to use a >>>connection for each session and check to see if its still valid each >> > time it > >>>is needed? There are many lookup lists >>>maintained in sessions as ArrayLists. Should those be made >>>application-level? I also have a number of static >>>factory classes that perform database/business logic. Should those be >> > made > >>>into Singletons? What is a good monitoring tool >>>for development on Win2000? The server is Linux but I have no way of >> > seeing > >>>how big the load is....any help >>>would be greatly appreciated. >>> >>>Thanks, >>>Bill >> >> >> >> >>-- >>To unsubscribe, e-mail: > > <mailto:[EMAIL PROTECTED]> > >>For additional commands, e-mail: > > <mailto:[EMAIL PROTECTED]> >
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