PHP实现货币换算的方法

本文实例讲述了PHP实现货币换算的方法。分享给大家供大家参考。

具体实现代码如下：

<?php 

/* 

* File: CurrencyConverter.php 

* Author: Simon Jarvis 

* Copyright: 2005 Simon Jarvis 

* Date: 10/12/05 

* Link: http://www.white-hat-web-design.co.uk/articles/php-currency-conversion.php 

* 

* This program is free software; you can redistribute it and/or 

* modify it under the terms of the GNU General Public License 

* as published by the Free Software Foundation; either version 2 

* of the License, or (at your option) any later version. 

* 

* This program is distributed in the hope that it will be useful, 

* but WITHOUT ANY WARRANTY; without even the implied warranty of 

* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 

* GNU General Public License for more details: 

* http://www.gnu.org/licenses/gpl.html 

* 

*/ 

class CurrencyConverter { 

   var $xml_file = "www.ecb.int/stats/eurofxref/eurofxref-daily.xml"; 

   var $mysql_host, $mysql_user, $mysql_pass, $mysql_db, $mysql_table; 

   var $exchange_rates = array(); 

   //Load Currency Rates 

   function CurrencyConverter($host,$user,$pass,$db,$tb) { 

      $this->mysql_host = $host; 

      $this->mysql_user = $user; 

      $this->mysql_pass = $pass; 

      $this->mysql_db = $db; 

      $this->mysql_table = $tb; 

      $this->checkLastUpdated(); 

      $conn = mysql_connect($this->mysql_host,$this->mysql_user,$this->mysql_pass); 

      $rs = mysql_select_db($this->mysql_db,$conn); 

      $sql = "SELECT * FROM ".$this->mysql_table; 

      $rs =  mysql_query($sql,$conn); 

      while($row = mysql_fetch_array($rs)) { 

         $this->exchange_rates[$row['currency']] = $row['rate']; 

      } 

   } 

   /* Perform the actual conversion, defaults to £1.00 GBP to USD */ 

   function convert($amount=1,$from="GBP",$to="USD",$decimals=2) { 

      return(number_format(($amount/$this->exchange_rates[$from])*$this->exchange_rates[$to],$decimals)); 

   } 

   /* Check to see how long since the data was last updated */ 

   function checkLastUpdated() { 

      $conn = mysql_connect($this->mysql_host,$this->mysql_user,$this->mysql_pass); 

      $rs = mysql_select_db($this->mysql_db,$conn); 

      $sql = "SHOW TABLE STATUS FROM ".$this->mysql_db." LIKE '".$this->mysql_table."'"; 

      $rs =  mysql_query($sql,$conn); 

      if(mysql_num_rows($rs) == 0 ) { 

         $this->createTable(); 

      } else { 

         $row = mysql_fetch_array($rs); 

         if(time() > (strtotime($row["Update_time"])+(12*60*60)) ) { 

            $this->downloadExchangeRates(); 

         } 

      } 

   } 

   /* Download xml file, extract exchange rates and store values in database */ 

   function downloadExchangeRates() { 

      $currency_domain = substr($this->xml_file,0,strpos($this->xml_file,"/")); 

      $currency_file = substr($this->xml_file,strpos($this->xml_file,"/")); 

      $fp = @fsockopen($currency_domain, 80, $errno, $errstr, 10); 

      if($fp) { 

         $out = "GET ".$currency_file." HTTP/1.1rn"; 

         $out .= "Host: ".$currency_domain."rn"; 

         $out .= "User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8) Gecko/20051111 Firefox/1.5rn"; 

         $out .= "Connection: Closernrn"; 

         fwrite($fp, $out); 

         while (!feof($fp)) { 

            $buffer .= fgets($fp, 128); 

         } 

         fclose($fp); 

         $pattern = "{<Cubes*currency='(w*)'s*rate='([d.]*)'/>}is"; 

         preg_match_all($pattern,$buffer,$xml_rates); 

         array_shift($xml_rates); 

         for($i=0;$i<count($xml_rates[0]);$i++) { 

            $exchange_rate[$xml_rates[0][$i]] = $xml_rates[1][$i]; 

         } 

         $conn = mysql_connect($this->mysql_host,$this->mysql_user,$this->mysql_pass); 

         $rs = mysql_select_db($this->mysql_db,$conn); 

         foreach($exchange_rate as $currency=>$rate) { 

            if((is_numeric($rate)) && ($rate != 0)) { 

               $sql = "SELECT * FROM ".$this->mysql_table." WHERE currency='".$currency."'"; 

               $rs =  mysql_query($sql,$conn) or die(mysql_error()); 

               if(mysql_num_rows($rs) > 0) { 

                  $sql = "UPDATE ".$this->mysql_table." SET rate=".$rate." WHERE currency='".$currency."'"; 

               } else { 

                  $sql = "INSERT INTO ".$this->mysql_table." VALUES('".$currency."',".$rate.")"; 

               } 

               $rs =  mysql_query($sql,$conn) or die(mysql_error()); 

            } 

         } 

      } 

   } 

   /* Create the currency exchange table */ 

   function createTable() { 

      $conn = mysql_connect($this->mysql_host,$this->mysql_user,$this->mysql_pass); 

      $rs = mysql_select_db($this->mysql_db,$conn); 

      $sql = "CREATE TABLE ".$this->mysql_table." ( currency char(3) NOT NULL default '', rate float NOT NULL default '0', PRIMARY KEY(currency) ) ENGINE=MyISAM"; 

      $rs =  mysql_query($sql,$conn) or die(mysql_error()); 

      $sql = "INSERT INTO ".$this->mysql_table." VALUES('EUR',1)"; 

      $rs =  mysql_query($sql,$conn) or die(mysql_error()); 

      $this->downloadExchangeRates(); 

   } 

} 

?>

<?php 

   include('CurrencyConverter.php'); 

   $x = new CurrencyConverter('your_host','your_username','your_password','your_database_name','your_table_name'); 

   echo $x->convert(2.50,'GBP','USD'); 

?>

希望本文所述对大家的php程序设计有所帮助。