package com.atguigu.utils;

import java.io.IOException;

import java.sql.Connection;

import java.sql.DriverManager;

import java.sql.ResultSet;

import java.sql.SQLException;

import java.sql.Statement;

import java.util.Properties;

/*

 * 工具类：

 * 1、注册驱动：只要运行一次

 * 2、获取连接

 * 3、关闭资源

 */

public class JDBCUtils {

         private static String drivername;

         private static String url;

         private static String user;

         private static String password;

         private static Properties pro = new Properties();

         static{

                  try {

                          //加载，读取jdbc.properties配置的信息

                          //pro.load的作用是把jdbc.properties文件中配置的信息，一一put到pro这个map中

                          pro.load(ClassLoader.getSystemClassLoader().getResourceAsStream(“jdbc.properties”));

//                       drivername = pro.getProperty(“key”)

                          drivername = pro.getProperty(“drivername”);

                          url = pro.getProperty(“url”);

                          user = pro.getProperty(“user”);

                          password = pro.getProperty(“password”);

                          //注册驱动，加载驱动

                          Class.forName(drivername);

                  } catch (ClassNotFoundException e) {

                          e.printStackTrace();

                  } catch (IOException e) {

                          e.printStackTrace();

                  }

         }

         public static Connection getConnection()throws SQLException{

                  Connection conn = DriverManager.getConnection(url, user, password);

                  return conn;

         }

         public static void closeQuietly(Connection conn){

                  try {

                          if(conn!=null){

                                   conn.close();

                          }

                  } catch (SQLException e) {

                          e.printStackTrace();

                  }

         }

         public static void closeQuietly(Statement st){

                  try {

                          if(st!=null){

                                   st.close();

                          }

                  } catch (SQLException e) {

                          e.printStackTrace();

                  }

         }

         public static void closeQuietly(ResultSet rs){

                  try {

                          if(rs!=null){

                                   rs.close();

                          }

                  } catch (SQLException e) {

                          e.printStackTrace();

                  }

         }

         public static void closeQuietly(Statement st,Connection conn){

                  closeQuietly(st);

                  closeQuietly(conn);

         }

         public static void closeQuietly(ResultSet rs,Statement st,Connection conn){

                  closeQuietly(rs);

                  closeQuietly(st);

                  closeQuietly(conn);

         }

}