Hi Brian,
Examples can be found here:
http://svn.apache.org/repos/asf/jakarta/commons/proper/dbcp/trunk/doc/
If you are creating a BasicDataSource yourself then you need to keep it
in a static variable somewhere. You create it once and only close the
datasource when your application is shutting down. The BasicDataSource
contains the pool and you only want one of these around for each
database(scheme) you want to connect to.
Your program then uses ds.getConnection() / conn.close() to get/return
connections from/to the pool.
Use the pattern Craig gave you to make sure you always close the
rs/stmt/conn.
So key point here is to only create one datasource (and store it in a
static somewhere) and not to close the datasource after each call.
Cheers
Dirk
Brian Cook wrote:
I have several apps written that use org.apache.commons.dbcp. And I am
getting the org.apache.commons.dbcp.SQLNestedException: Cannot get a
connection, pool exhausted exception.
When I run netstat sure enough it shows about 60 - 100 "ESTABLISHED"
connections open at any given time. Looking deeper it looks like new
connections are created most but not each time the Java Bean the uses
the data base is called. So it seems pretty clear that I am failing to
close all of the connections in my app. My problem is that I can not
find where that is.
My understanding is that as long as I close every ResultSet, and each
Connection object I should have my bases covered. I have gone back
though the app repeatedly and verified that all the ResultSets,
Connections, and BasicDataSource objects are all being closed.
Due to an internal political problem I am not using JNDI for the
connections. Instead I have a class file that is called when a
connection is need. After the object is used a close() method is called
and closes the Statement, Connection, ResultSet, BasicDataSource objects.
So my questions are ..
1. Is there something else I should be doing to return the
connections to the pool?
2. Does not using JNDI with org.apache.commons.dbcp cause problems
with closing the connection pool some how?
I have been though about 6 months of the archives for this list and did
not find any hints, I went to look at the "examples" lnik at on the
Commons.DBCP page but the link to
http://cvs.apache.org/downviewcvs.html/jakarta-commons/dbcp/doc/ seems
to be broken. Googling has only just returned the usall advice of make
sure you are closing every connection.
I am open to any ideas or thoughts to what I am failing to due here.
Details and the code are included below.
OS: Linux Red Hat 9.0
Container: Tomcat 4.127
DBCP: commons-dbcp-1.2.1.jar, commons-pool-1.2.jar
JDK: 1.5
Database: MySQL 4.1
JDBC Driver: mysql-connector-java-3.1.7-bin.jar
public class DBConector {
<Omited Code/>
public DBConector(String dataBaseName) {
try{
String DataBaseURL = "jdbc:mysql://"+DataBaseHost+"/"+dataBaseName+
"?user="+DataBaseUser+"&password="+DataBasePassword;
mysqlCon = getPooledConection(DataBaseURL);
sqlStatement = mysqlCon.createStatement();
}
catch(Exception s) {
System.err.println(new java.util.Date()+" Error throw by" +
" DBConector()\n"+s);
}
}
<Omited Code/>
public ResultSet read(String SQL) {
try{
rs = sqlStatement.executeQuery( SQL );
} // Close try
catch(Exception s) {
System.err.println(new java.util.Date()+" Error throw by an
SQL " +
"call in DBConector.read() class : \n"+s+"\n"+s.getMessage()+
"\nSQL Queary : "+SQL+"\n");
} // Close catch
return(DataFromDB);
} // Close the read method
<Omited Code/>
protected static Connection getPooledConection(String connectURI) {
ds = new BasicDataSource();
ds.setDriverClassName(DBDriver);
ds.setUsername(DataBaseUser);
ds.setPassword(DataBasePassword);
ds.setUrl(connectURI);
ds.setInitialSize(3);
ds.setMaxActive(32);
ds.setMaxIdle(8);
ds.setMinIdle(3);
Connection con = null;
try {
con = ds.getConnection();
}
catch(Exception a){System.out.println(new java.util.Date() +
"PrintTimeDataBase6.getPooledConection() has thrown an
exception.\n"+a+
"\n"+ a.getMessage() );
}
return con;
} // Close method
<Omited Code/>
public void close() {
try { sqlStatement.close(); } catch(Exception a) { }
try { mysqlCon.close(); } catch(Exception a) { }
try { rs.close(); } catch(Exception a) { }
try { ds.close(); } catch(Exception a) { }
} // Close method
} // Close the PrintTimeWebServices Class
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