C3p0 connection pool template,

C3p0 connection pool template,

A connection pool is a technology used to create and manage a connection buffer pool. These connections are ready for use by any thread that needs them.

Now I am creating a template for the p3c0 connection pool.

First, p3c0 is open-source, so go to the official website to download the p3c0 jar package. Import data in the project and download the driver for your database connection.

 

The connection pool template code is as follows:

Package com. fish;

 

Import java. beans. PropertyVetoException;

Import java. SQL. Connection;

Import java. SQL. PreparedStatement;

Import java. SQL. ResultSet;

Import java. SQL. SQLException;

Import java. SQL. Statement;

Import java. util. ResourceBundle;

 

Import com. mchange. v2.c3p0. ComboPooledDataSource;

 

/**

* The tool class used to connect to the database is defined as non-inherited and private access.

*/

Public final class DBTool {

// Confidence in configuring the connection pool using the configuration file. This is the name of the configuration file.

Final private static String OPTION_FILE_NAME = "mysqldatabase ";

Private static Connection conn;

 

Static ResourceBundle res;

// Connection pool class

Static ComboPooledDataSource CPPS;

 

Static {

// Obtain the file from the configuration file

Res = ResourceBundle. getBundle (OPTION_FILE_NAME );

// Create a connection pool

CPPS = new ComboPooledDataSource ();

// Driver name

String driver = res. getString ("jdbc. driver ");

// Connection url

String url = res. getString ("jdbc. url ");

// Database username

String user = res. getString ("jdbc. username ");

// Database Password

String password = res. getString ("jdbc. password ");

// Maximum number of connections in the connection pool

String poolMax = res. getString ("c3p0. maxPoolSize ");

// The minimum number of connections in the connection pool

String poolMin = res. getString ("c3p0. minPoolSize ");

// Number of connections allowed when resources are exhausted

String PoolAcquireIncrement = res. getString ("c3p0. acquireIncrement ");

 

Try {

CPPS. setDriverClass (driver );

} Catch (PropertyVetoException e ){

System. out. println ("driver not found ");

}

CPPS. setJdbcUrl (url );

CPPS. setUser (user );

CPPS. setPassword (password );

CPPS. setMinPoolSize (Integer. parseInt (poolMin ));

CPPS. setAcquireIncrement (Integer. parseInt (PoolAcquireIncrement ));

CPPS. setMaxPoolSize (Integer. parseInt (poolMax ));

 

}

 

/**

* Obtain the database connection

*

* @ Return conn

*/

Public static Connection getConnection (){

Try {

Conn = CPPS. getConnection ();

} Catch (SQLException e ){

System. out. println ("connection failed ");

}

Return conn;

}

 

/**

* Release resources

*

*/

Public static void closeJDBC (Connection conn, Statement statement,

ResultSet rs ){

If (null! = Rs ){

Try {

Rs. close ();

} Catch (SQLException e ){

E. printStackTrace ();

Throw new RuntimeException (e );

} Finally {

If (null! = Statement ){

Try {

Statement. close ();

} Catch (SQLException e ){

E. printStackTrace ();

Throw new RuntimeException (e );

} Finally {

If (null! = Conn ){

Try {

Conn. close ();

} Catch (SQLException e ){

E. printStackTrace ();

Throw new RuntimeException (e );

}

}

}

}

}

}

}

}

 

2. The mysqldatabase. properties file is as follows:

 

Jdbc. driver = com. mysql. jdbc. Driver

Jdbc. url = jdbc: mysql: /127.0.0.1: 3306/datacenter3

Jdbc. username = root

Jdbc. password = 1234

C3p0. maxPoolSize = 30

C3p0. minPoolSize = 10

C3p0. acquireIncrement = 10

 

In the future, you can directly modify the database you want to connect to in this file.

 

Test: Example

Package com. fish;

Public class Test2 {

Public static void main (String [] args) throws Exception {

System. out. println (DBTool. getConnection ());

}

}

 

Output result:

14:44:04 com. mchange. v2.log. MLog <clinit>

Message: MLog clients using java 1.4 + standard logging.

2014-11-16 14:44:04 com. mchange. v2.c3p0. C3P0Registry banner

Information: Initializing c3p0-0.9.2.1 [built 20-March-2013 11:16:28 + 0000; debug? True; trace: 10]

14:44:04 com. mchange. v2.c3p0. impl. AbstractPoolBackedDataSource getPoolManager

Information: Initializing c3p0 pool... com. mchange. v2.c3p0. comboPooledDataSource [acquireIncrement-> 10, latency-> 30, acquireRetryDelay-> 1000, autoCommitOnClose-> false, automaticTestTable-> null, disable-> false, checkoutTimeout-> 0, connectionCustomizerClassName-> null, connectionTesterClassName-> com. mchange. v2.c3p0. impl. defaultConnectionTester, dataSourceName-> 1hge1d1951evdfumup12ui | 5ffb18, debugUnreturnedConnectionStackTraces-> false, description-> null, driverClass-> com. mysql. jdbc. driver, factoryClassLocation-> null, Token-> false, identityToken-> token | 5ffb18, idleConnectionTestPeriod-> 0, initialPoolSize-> 3, jdbcUrl-> jdbc: mysql: // 127.0.0.1: 3306/datacenter3, latency-> 0, maxConnectionAge-> 0, maxIdleTime-> 0, maxIdleTimeExcessConnections-> 0, maxPoolSize-> 30, maxStatements-> 0, maxStatementsPerConnection-> 0, minPoolSize-> 10, numHelperThreads-> 3, preferredTestQuery-> null, properties-> {user = ******, password = ******}, propertyCycle-> 0, success-> 0, testConnectionOnCheckin-> false, testConnectionOnCheckout-> false, unreturnedConnectionTimeout-> 0, userOverrides->{}, success-> false]

Com. mchange. v2.c3p0. impl. NewProxyConnection @ d19bc8