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?public void closeConnection(Connection conn) throws SQLException {
??if ( log.isDebugEnabled() ) checkedOut--;
//synchronized?pool to avoid concurrence error.??
synchronized (pool) {
???int currentSize = pool.size();
???if ( currentSize < poolSize ) {
????if ( log.isTraceEnabled() ) log.trace("returning connection to pool, pool size: " + (currentSize + 1) );
//add to pool??
????pool.add(conn);
????return;
???}
??}
??log.debug("closing JDBC connection");
??conn.close();
?}
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?public Connection getConnection() throws SQLException {
??if ( log.isTraceEnabled() ) log.trace( "total checked-out connections: " + checkedOut );
//synchronized?pool to avoid concurrence error
???
?synchronized (pool) {
???if ( !pool.isEmpty() ) {
//if the pool is not empty,return connection from the pool??
????
????int last = pool.size() - 1;
????if ( log.isTraceEnabled() ) {
?????log.trace("using pooled JDBC connection, pool size: " + last);
?????checkedOut++;
????}
????Connection pooled = (Connection) pool.remove(last);
????if (isolation!=null) pooled.setTransactionIsolation( isolation.intValue() );
????if ( pooled.getAutoCommit()!=autocommit ) pooled.setAutoCommit(autocommit);
????return pooled;
???}
??}
??log.debug("opening new JDBC connection");
//create new connection.
??Connection conn = DriverManager.getConnection(url, connectionProps);
??if (isolation!=null) conn.setTransactionIsolation( isolation.intValue() );
??if ( conn.getAutoCommit()!=autocommit ) conn.setAutoCommit(autocommit);
??if ( log.isDebugEnabled() ) {
???log.debug( "created connection to: " + url + ", Isolation Level: " + conn.getTransactionIsolation() );
??}
??if ( log.isTraceEnabled() ) checkedOut++;
??return conn;
?}
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so you can see that when the connection will close,it actually not close and add to the pool if the pool size is not full.
in other way , we can?firstly create a number of connection in the pool and when the pool is used out then create new connection to the call.
I will see the C3P0ConnectionProvider next.
A connection provider that uses java.sql.DriverManager. This provider
?also implements a very
rudimentary connection pool.
Note that you have to copy the required library into your classpath and use different connection pooling settings if you want to use a
production-quality third party JDBC pooling software.
posted on 2006-11-08 12:23
R.Zeus 閱讀(678)
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