package org.jdbc.test;

 import java.io.InputStream;

 import java.sql.Connection;

 import java.sql.Driver;

 import java.sql.DriverManager;

 import java.sql.PreparedStatement;

 import java.sql.ResultSet;

 import java.sql.SQLException;

 import java.util.Properties;

 public class DBUtil {

     /*

      * 编写一个通用的方法，在不修改程序的情况下，可以获取任何数据库的连接

      * 解决方案：把数据库驱动Driver实现类的全类名、url、user、password

      * 放入一个配置文件中，通过修改配置文件的方式实现和具体的数据库解耦

      */

     public static Connection getConnection2() throws Exception{

     String driverClass = null;

     String jdbcUrl = null;

     String user = null;

     String password = null;

     // 读取类路径下的jdbc.properties文件

     InputStream in =DBUtil.class.getClassLoader().getResourceAsStream("jdbc.properties");

     Properties properties = new Properties();

     properties.load(in);

     driverClass = properties.getProperty("driver");

     jdbcUrl = properties.getProperty("jdbcUrl");

     user = properties.getProperty("user");

     password = properties.getProperty("password");

     Driver driver = (Driver)Class.forName(driverClass).newInstance();

     Properties info = new Properties();

     info.put("user", user);

     info.put("password", password);

     Connection connection = driver.connect(jdbcUrl, info);

     return connection;

     }

     /**

      * 获取数据库连接

      *

      * @return

      */

     public static Connection getConnection() {

         try {

             String url = "jdbc:mysql://127.0.0.1:3306/crm?user=root&password=root";

             // 加载驱动

             Class.forName("com.mysql.jdbc.Driver");

             // 获取连接

             //Connection con = DriverManager.getConnection(url);

             Connection con = DriverManager.getConnection(url);

             return con;

         } catch (Exception e) {

             e.printStackTrace();

         }

         return null;

     }

     /**

      * 关闭连接

      * @param con

      */

     public static void  closeCon(Connection con){

         try {

             con.close();

         } catch (SQLException e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         }

     }

     /**

      * 关闭实例

      * @param pre

      */

     public static void  closePre(PreparedStatement pre){

         try {

             pre.close();

         } catch (SQLException e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         }

     }

     /**

      * 关闭结果集

      * @param res

      */

     public static void  closeRes(ResultSet res){

         try {

             res.close();

         } catch (SQLException e) {

             // TODO Auto-generated catch block

             e.printStackTrace();

         }

     }

 }