?? complexconstructorexample.java
字號:
import java.sql.*;
public class ComplexConstructorExample
{
// if you have a database running, change these to work for your environment
static String dbURL = "jdbc:mysql://localhost:3306/store_product";
static String dbUserName = "";
static String dbPassword = "";
static String dbDriver = "org.gjt.mm.mysql.Driver";
public static void main(String[] args)
{
ConnectionPool pool = null;
try
{
// open a pool of 10 connections - when I run low, open 5 more
// check my pool's health every 2 minutes, and keep "extra" idle
// connections alive for 3 minutes before closing them down
pool = new ConnectionPool( dbURL , dbUserName , dbPassword, dbDriver, 10, 5, 2, 3 );
}
catch(SQLException e) // thrown if problems building connections to database
{
System.out.println( e.getMessage() );
}
catch(ClassNotFoundException cnf) // thrown if db class driver not found in classpath
{
System.out.println( cnf.getMessage() );
}
// now that the pool is running, we can use it's connections...
Connection con = null;
try {
con = pool.getConnection(); // get a connection from the pool
// use the connection...
// ...
useConnection( con );
// done using the connection
pool.returnConnection( con ); // return the connection to the pool
System.out.println( pool.getReport() ); // let's see a report
}
catch(SQLException e) // thrown if problems building connections to database
{
System.out.println( e.getMessage() );
}
}
// simple example to use connection
public static void useConnection(Connection con) throws SQLException
{
System.out.println("Just displaying the tables in the current database...");
Statement statmt;
ResultSet res;
statmt = con.createStatement();
String statement = "show tables"; // some dumb query that should work everywhere
res = statmt.executeQuery(statement);
while ( res.next() )
System.out.println( res.getString(1) );
res.close();
statmt.close();
}
}
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