connectionfactory.java

电子商务系统： 项目描述：该系统主要完成用户网上购物、订单管理、产品管理、管理员管理等功能。后台管理员对产品类别和产品进行管理后

package com.tarena.shop.util;

import java.util.Properties;
import java.sql.*;
import java.io.*;
import javax.sql.DataSource;
import javax.naming.*;

public class ConnectionFactory
{
  private static Properties config = new Properties();
  
  static
  {
    try
    {
      InputStream in = ConnectionFactory.class.getClassLoader().getResourceAsStream("database-config.properties");
      config.load(in);
      in.close();
    }catch(Exception e)
    {
      e.printStackTrace();
      throw new ExceptionInInitializerError();
    }
  }
  
  public static Connection getConnection()
  {
    if(config.getProperty("jndiname") != null)
    {
      return getConnectionByDriverManager();
    }
    
    return getConnectionByJndi();
  }
  
  public static Connection getConnectionByDriverManager()
  {
    try
    {
      Class.forName(config.getProperty("driver"));
      return DriverManager.getConnection(config.getProperty("url")
                                          , config.getProperty("user")
                                          , config.getProperty("password"));
    }catch(ClassNotFoundException e)
    {
      e.printStackTrace();
      throw new RuntimeException("unable to find class " + config.getProperty("driver"));
    }catch(SQLException e)
    {
      e.printStackTrace();
      throw new RuntimeException("unable to connect database");
    }
  }
  
  public static Connection getConnectionByJndi()
  {
    try
    {
      Context ctx = new InitialContext();
      DataSource ds = (DataSource)ctx.lookup("java:comp/env/" + config.getProperty("jndiname"));
      return ds.getConnection();
    }catch(Exception e)
    {
      e.printStackTrace();
      throw new RuntimeException("unable to get connection from " + config.getProperty("jndiname"));
    }
  }
  
  public static void main(String[] args) throws Exception
  {
    Connection con = ConnectionFactory.getConnection();
    System.out.println(con);
    con.close();
  }
}