C3p0 creates a connection pool,

C3p0 creates a connection pool,
C3p0 is currently the most widely used database connection pool

Feature: the auto-collect connection feature is available;

Asynchronous execution is available.

Use c3p0 to export packages, link https://sourceforge.net/projects/c3p0/

Package to be imported: c3p0-0.9.5.2-sources.jar mchange-commons-java-0.2.11-sources.jar

Detailed usage of the c3p0 decompression package under doc (all in English)

Core class: ComboPooledDataSource

Profile: Must be called c3p0-config.xml

Java code:

Public class C3p0 {

Private static ComboPooledDataSource ds = null;

// Static code block

Static {

Ds = new ComboPooledDataSource ();

}

Public static Connection getConnection (){

Try {

// Get a Connection object through ds
Return ds. getConnection ();
} Catch (SQLException e ){
E. printStackTrace ();
}
Return null;

}

　　

Public static void main (String [] args ){
For (int I = 0; I <5; I ++ ){

// Output the connection in the console
System. out. println (getCon ());
}
}

}

Configuration file:

<C3p0-config>
<! -- Default configuration -->
<Default-config>
<Property name = "jdbcUrl"> jdbc: mysql: // localhost: 3306/test </property>
<Property name = "user"> root </property>

<Property name = "password"> 123123 </property>

<! -- Database-driven -->
<Property name = "driverClass"> com. mysql. jdbc. Driver </property>

<! -- Initialization value in connection pool -->
<Property name = "initialPoolSize"> 5 </property>

<! -- Maximum value in connection pool -->
<Property name = "maxPoolSize"> 10 </property>

<! -- Exceeds the maximum wait time -->
<Property name = "checkoutTimeout"> 3000 </property>
</Default-config>

<! -- Configure by name intergalactoApp -->
<Named-config name = "intergalactoApp">
<Property name = "jdbcUrl"> jdbc: mysql: // localhost: 3306/test </property>
<Property name = "user"> root </property>
<Property name = "password"> 123123 </property>
<Property name = "driverClass"> com. mysql. jdbc. Driver </property>
<Property name = "initialPoolSize"> 10 </property>
<Property name = "maxPoolSize"> 20 </property>
<Property name = "checkoutTimeout"> 5000 </property>
</Named-config>
C3p0-config>