读取并配置c3p0，并获得Connection对象

/*

driver.class=com.mysql.jdbc.Driver
jdbc.url=
user=
password=

min.pool.size=5
max.pool.size=20
acquire.increment=5

*/

package com.greatchn.htcwweb.dto;

import java.sql.Connection;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.Properties;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import com.mchange.v2.c3p0.ComboPooledDataSource;
import com.mchange.v2.c3p0.DataSources;

public class ConnectionPool {  
  
    private static Log _log = LogFactory.getLog(ConnectionPool.class);  
 
    private static ConnectionPool _instance = new ConnectionPool();  
 
    private Properties _props;  
    private ComboPooledDataSource _cpds;  
   
   
    public static void cleanUp(Connection con) {  
        _instance._cleanUp(con);  
    }  
    public static void cleanUp(Connection con, Statement s) {  
        _instance._cleanUp(con, s);  
    }  
    public static void cleanUp(Connection con, Statement s, ResultSet rs) {  
        _instance._cleanUp(con, s, rs);  
    }  
    public static void destroy() throws SQLException {  
        _instance._destroy();  
    }  
 
    public static Connection getConnection() throws SQLException {  
        return _instance._getConnection();  
    }  
      
    public static Properties getProperties() {  
        return _instance._props;  
    }  
 
    private ConnectionPool() {  
        try {  
 
            // Properties  
 
            ClassLoader classLoader = getClass().getClassLoader();  
 
            _props = new Properties();  
 
            _props.load(classLoader.getResourceAsStream(  
                "connection-pool.properties"));  
 
            _props.list(System.out);  
 
            // Pooled data source  
 
            String driverClass = _props.getProperty("driver.class");  
            String jdbcUrl = _props.getProperty("jdbc.url");  
            String user = _props.getProperty("user");  
            String password = _props.getProperty("password");  
 
            int minPoolSize = 5;  
 
            try {  
                minPoolSize = Integer.parseInt(  
                    _props.getProperty("min.pool.size"));  
            }  
            catch (Exception e) {  
            }  
 
            int maxPoolSize = 5;  
 
            try {  
                maxPoolSize = Integer.parseInt(  
                    _props.getProperty("max.pool.size"));  
            }  
            catch (Exception e) {  
            }  
 
            int acquireIncrement = 5;  
 
            try {  
                acquireIncrement = Integer.parseInt(  
                    _props.getProperty("acquire.increment"));  
            }  
            catch (Exception e) {  
            }  
 
            _cpds = new ComboPooledDataSource();  
 
            _cpds.setDriverClass(driverClass);  
            _cpds.setJdbcUrl(jdbcUrl);  
            _cpds.setUser(user);  
            _cpds.setPassword(password);  
 
            _cpds.setMinPoolSize(minPoolSize);  
            _cpds.setMaxPoolSize(maxPoolSize);  
            _cpds.setAcquireIncrement(acquireIncrement);  
        }  
        catch (Exception e) {  
            _log.error(e);  
        }  
    }  
 
    private void _cleanUp(Connection con) {  
        _cleanUp(con, null, null);  
    }  
 
    private void _cleanUp(Connection con, Statement s) {  
        _cleanUp(con, s, null);  
    }  
 
    private void _cleanUp(Connection con, Statement s, ResultSet rs) {  
        try {  
            if (rs != null) {  
                rs.close();  
            }  
        }  
        catch (SQLException sqle) {  
            _log.error(sqle);  
        }  
 
        try {  
            if (s != null) {  
                s.close();  
            }  
        }  
        catch (SQLException sqle) {  
            _log.error(sqle);  
        }  
 
        try {  
            if (con != null) {  
                con.close();  
            }  
        }  
        catch (SQLException sqle) {  
            _log.error(sqle);  
        }  
    }  
 
    private void _destroy() throws SQLException {  
        DataSources.destroy(_cpds);  
    }  
 
    private Connection _getConnection() throws SQLException {  
        return _cpds.getConnection();  
    }  

 
}