数据库连接池 c3p0 demo 代码和分析

import java.sql.Connection;
import java.sql.SQLException;
import java.beans.PropertyVetoException;
import com.mchange.v2.c3p0.ComboPooledDataSource;

public class Dafa {
    private static DBPool dbPool;
    private ComboPooledDataSource dataSource;

    static {
        dbPool = new DBPool();
    }

    public Dafa() {
        try {
            dataSource = new ComboPooledDataSource();
            dataSource.setUser("id ");
            dataSource.setPassword("pw ");
            dataSource.setJdbcUrl("jdbc:mysql://127.0.0.1:3306/test?autoReconnect=true&useUnicode=true&characterEncoding=GB2312 ");
            dataSource.setDriverClass("com.mysql.jdbc.Driver ");
            dataSource.setInitialPoolSize(2);
            dataSource.setMinPoolSize(1);
            dataSource.setMaxPoolSize(10);
            dataSource.setMaxStatements(50);
            dataSource.setMaxIdleTime(60);
        } catch (PropertyVetoException e) {
            throw new RuntimeException(e);
        }
    }

    public final static DBPool getInstance() {
        return dbPool;
    }

    public final Connection getConnection() {
        try {
            return dataSource.getConnection();
        } catch (SQLException e) {
            throw new RuntimeException("无法从数据源获取连接 ", e);
        }
    }

    public static void main(String[] args) throws SQLException {
        Connection con = null;
        try {
            con = DBPool.getInstance().getConnection();
        } catch (Exception e) {
        } finally {
            if (con != null)
                con.close();
        }
    }

}