jdbc question 1

[tvrtko]

I use connection pooling with Tomcat. I configured connection poll in Tomcat server configuration file
and access it via JNDI. Everything works fine, just compiler gives warning: "ZadaciAction.java uses unchecked or unsafe operations".
This is the piece of code where that happens:


try
{
InitialContext ctx = new InitialContext();

DataSource ds = (DataSource)ctx.lookup("java:comp/env/jdbc/MyDB");

conn = ds.getConnection(); // Connection object

String query = "SELECT * FROM zadaci where godina = ? and rok = ?";

stmt = conn.prepareStatement(query);

stmt.setString(1, (String)rundata.getSession().getAttribute(Defines.GODINA));

rs = stmt.executeQuery();

while (rs.next()){

Zadaci zadatak = new Zadaci(rs.getString(3), rs.getString(4), cTemp); // my object

zadaci.add(nTemp, zadatak); // ArrayList object

nTemp = nTemp + 1; // integer counter
}

}
catch (Exception e)
{
rundata.setMessage("Greska: " + e.toString());
rundata.setStackTrace(org.apache.turbine.util.StringUtils.stackTrace(e), e);

} finally {

if (rs != null) {
try { rs.close(); } catch (SQLException e) { ; }
rs = null;
}
if (rs1 != null) {
try { rs1.close(); } catch (SQLException e) { ; }
rs1 = null;
}
if (stmt != null) {
try { stmt.close(); } catch (SQLException e) { ; }
stmt = null;
}
if (stmt1 != null) {
try { stmt1.close(); } catch (SQLException e) { ; }
stmt1 = null;
}
if (conn != null) {
try { conn.close(); } catch (SQLException e) { ; }
conn = null;
}
}

What is the reason?

Is it necessery to sinchronize getting connection
"conn = ds.getConnection();"
or sinchronization is implemented in getConnection() method?

Can I put DataSource object in the context and share it among users?
Are there any synchronization issues about that?


Thanks in advance.

 

[Diancecht]

http://forum.java.sun.com/thread.jspa?threadID=584311&tstart=0

Cheers,
Dian

 

[tvrtko]

Thanks for your help.
It solved my problem.