非常实用的PHP常用函数汇总_php技巧

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本文实例总结了一些在php应用开发中常用到的函数,这些函数有字符操作,文件操作及其它的一些操作了,分享给大家供大家参考。具体如下:

1、PHP加密解密

PHP加密和解密函数可以用来加密一些有用的字符串存放在数据库里,并且通过可逆解密字符串,该函数使用了base64和MD5加密和解密。
function encryptDecrypt($key, $string, $decrypt){
    if($decrypt){
        $decrypted = rtrim(mcrypt_decrypt(MCRYPT_RIJNDAEL_256, md5($key), base64_decode($string), MCRYPT_MODE_CBC, md5(md5($key))), "12");
        return $decrypted;
    }else{
        $encrypted = base64_encode(mcrypt_encrypt(MCRYPT_RIJNDAEL_256, md5($key), $string, MCRYPT_MODE_CBC, md5(md5($key))));
        return $encrypted;
    }
}
使用方法如下:
//以下是将字符串“Helloweba欢迎您”分别加密和解密
//加密:
echo encryptDecrypt('password', 'Helloweba欢迎您',0);
//解密:
echo encryptDecrypt('password', 'z0JAx4qMwcF+db5TNbp/xwdUM84snRsXvvpXuaCa4Bk=',1);
2、PHP生成随机字符串

当我们需要生成一个随机名字,临时密码等字符串时可以用到下面的函数:
function generateRandomString($length = 10) {
    $characters = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';
    $randomString = '';
    for ($i = 0; $i < $length; $i++) {
        $randomString .= $characters[rand(0, strlen($characters) - 1)];
    }
    return $randomString;
}
使用方法如下:
echo generateRandomString(20);
3、PHP获取文件扩展名(后缀)

以下函数可以快速获取文件的扩展名即后缀。
function getExtension($filename){
  $myext = substr($filename, strrpos($filename, '.'));
  return str_replace('.','',$myext);
}
使用方法如下:
$filename = '我的文档.doc';
echo getExtension($filename);
4、PHP获取文件大小并格式化

以下使用的函数可以获取文件的大小,并且转换成便于阅读的KB,MB等格式。
function formatSize($size) {
    $sizes = array(" Bytes", " KB", " MB", " GB", " TB", " PB", " EB", " ZB", " YB");
    if ($size == 0) { 
        return('n/a'); 
    } else {
      return (round($size/pow(1024, ($i = floor(log($size, 1024)))), 2) . $sizes[$i]); 
    }
}
使用方法如下:
$thefile = filesize('test_file.mp3');
echo formatSize($thefile);
5、PHP替换标签字符

有时我们需要将字符串、模板标签替换成指定的内容,可以用到下面的函数:
function stringParser($string,$replacer){
    $result = str_replace(array_keys($replacer), array_values($replacer),$string);
    return $result;
}
使用方法如下:
$string = 'The {b}anchor text{/b} is the {b}actual word{/b} or words used {br}to describe the link {br}itself';
$replace_array = array('{b}' => '<b>','{/b}' => '</b>','{br}' => '<br />');
 
echo stringParser($string,$replace_array);
6、PHP列出目录下的文件名

如果你想列出目录下的所有文件,使用以下代码即可:
function listDirFiles($DirPath){
    if($dir = opendir($DirPath)){
         while(($file = readdir($dir))!== false){
                if(!is_dir($DirPath.$file))
                {
                    echo "filename: $file<br />";
                }
         }
    }
}
使用方法如下:
listDirFiles('home/some_folder/');
7、PHP获取当前页面URL

以下函数可以获取当前页面的URL,不管是http还是https。
function curPageURL() {
    $pageURL = 'http';
    if (!empty($_SERVER['HTTPS'])) {$pageURL .= "s";}
    $pageURL .= "://";
    if ($_SERVER["SERVER_PORT"] != "80") {
        $pageURL .= $_SERVER["SERVER_NAME"].":".$_SERVER["SERVER_PORT"].$_SERVER["REQUEST_URI"];
    } else {
        $pageURL .= $_SERVER["SERVER_NAME"].$_SERVER["REQUEST_URI"];
    }
    return $pageURL;
}
使用方法如下:
echo curPageURL();
8、PHP强制下载文件

有时我们不想让浏览器直接打开文件,如PDF文件,而是要直接下载文件,那么以下函数可以强制下载文件,函数中使用了application/octet-stream头类型。
function download($filename){
    if ((isset($filename))&&(file_exists($filename))){
       header("Content-length: ".filesize($filename));
       header('Content-Type: application/octet-stream');
       header('Content-Disposition: attachment; filename="' . $filename . '"');
       readfile("$filename");
    } else {
       echo "Looks like file does not exist!";
    }
}
使用方法如下:
download('/down/test_45f73e852.zip');
9、PHP截取字符串长度

我们经常会遇到需要截取字符串(含中文汉字)长度的情况,比如标题显示不能超过多少字符,超出的长度用...表示,以下函数可以满足你的需求。
/*
 Utf-8、gb2312都支持的汉字截取函数
 cut_str(字符串, 截取长度, 开始长度, 编码);
 编码默认为 utf-8
 开始长度默认为 0
*/
function cutStr($string, $sublen, $start = 0, $code = 'UTF-8'){
    if($code == 'UTF-8'){
        $pa = "/[x01-x7f]|[xc2-xdf][x80-xbf]|xe0[xa0-xbf][x80-xbf]|[xe1-xef][x80-xbf][x80-xbf]|xf0[x90-xbf][x80-xbf][x80-xbf]|[xf1-xf7][x80-xbf][x80-xbf][x80-xbf]/";
        preg_match_all($pa, $string, $t_string);
 
        if(count($t_string[0]) - $start > $sublen) return join('', array_slice($t_string[0], $start, $sublen))."...";
        return join('', array_slice($t_string[0], $start, $sublen));
    }else{
        $start = $start*2;
        $sublen = $sublen*2;
        $strlen = strlen($string);
        $tmpstr = '';
 
        for($i=0; $i<$strlen; $i++){
            if($i>=$start && $i<($start+$sublen)){
                if(ord(substr($string, $i, 1))>129){
                    $tmpstr.= substr($string, $i, 2);
                }else{
                    $tmpstr.= substr($string, $i, 1);
                }
            }
            if(ord(substr($string, $i, 1))>129) $i++;
        }
        if(strlen($tmpstr)<$strlen ) $tmpstr.= "...";
        return $tmpstr;
    }
}
使用方法如下:
$str = "jQuery插件实现的加载图片和页面效果";
echo cutStr($str,16);
10、PHP获取客户端真实IP

我们经常要用数据库记录用户的IP,以下代码可以获取客户端真实的IP:
//获取用户真实IP
function getIp() {
    if (getenv("HTTP_CLIENT_IP") && strcasecmp(getenv("HTTP_CLIENT_IP"), "unknown"))
        $ip = getenv("HTTP_CLIENT_IP");
    else
        if (getenv("HTTP_X_FORWARDED_FOR") && strcasecmp(getenv("HTTP_X_FORWARDED_FOR"), "unknown"))
            $ip = getenv("HTTP_X_FORWARDED_FOR");
        else
            if (getenv("REMOTE_ADDR") && strcasecmp(getenv("REMOTE_ADDR"), "unknown"))
                $ip = getenv("REMOTE_ADDR");
            else
                if (isset ($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], "unknown"))
                    $ip = $_SERVER['REMOTE_ADDR'];
                else
                    $ip = "unknown";
    return ($ip);
}
使用方法如下:
echo getIp();
11、PHP防止SQL注入

我们在查询数据库时,出于安全考虑,需要过滤一些非法字符防止SQL恶意注入,请看一下函数:
function injCheck($sql_str) { 
    $check = preg_match('/select|insert|update|delete|'|/*|*|../|./|union|into|load_file|outfile/', $sql_str);
    if ($check) {
        echo '非法字符!!';
        exit;
    } else {
        return $sql_str;
    }
}
使用方法如下:
echo injCheck('1 or 1=1');
12、PHP页面提示与跳转

我们在进行表单操作时,有时为了友好需要提示用户操作结果,并跳转到相关页面,请看以下函数:
function message($msgTitle,$message,$jumpUrl){
    $str = '<!DOCTYPE HTML>';
    $str .= '<html>';
    $str .= '<head>';
    $str .= '<meta charset="utf-8">';
    $str .= '<title>页面提示</title>';
    $str .= '<style type="text/css">';
    $str .= '*{margin:0; padding:0}a{color:#369; text-decoration:none;}a:hover{text-decoration:underline}body{height:100%; font:12px/18px Tahoma, Arial,  sans-serif; color:#424242; background:#fff}.message{width:450px; height:120px; margin:16% auto; border:1px solid #99b1c4; background:#ecf7fb}.message h3{height:28px; line-height:28px; background:#2c91c6; text-align:center; color:#fff; font-size:14px}.msg_txt{padding:10px; margin-top:8px}.msg_txt h4{line-height:26px; font-size:14px}.msg_txt h4.red{color:#f30}.msg_txt p{line-height:22px}';
    $str .= '</style>';
    $str .= '</head>';
    $str .= '<body>';
    $str .= '<div class="message">';
    $str .= '<h3>'.$msgTitle.'</h3>';
    $str .= '<div class="msg_txt">';
    $str .= '<h4 class="red">'.$message.'</h4>';
    $str .= '<p>系统将在 <span style="color:blue;font-weight:bold">3</span> 秒后自动跳转,如果不想等待,直接点击 <a href="{$jumpUrl}">这里</a> 跳转</p>';
    $str .= "<script>setTimeout('location.replace('".$jumpUrl."')',2000)</script>";
    $str .= '</div>';
    $str .= '</div>';
    $str .= '</body>';
    $str .= '</html>';
    echo $str;
}
使用方法如下:
message('操作提示','操作成功!','http://www.jb51.net/');
13、PHP计算时长

我们在处理时间时,需要计算当前时间距离某个时间点的时长,如计算客户端运行时长,通常用hh:mm:ss表示。
function changeTimeType($seconds) {
    if ($seconds > 3600) {
        $hours = intval($seconds / 3600);
        $minutes = $seconds % 3600;
        $time = $hours . ":" . gmstrftime('%M:%S', $minutes);
    } else {
        $time = gmstrftime('%H:%M:%S', $seconds);
    }
    return $time;
}
使用方法如下:
$seconds = 3712;
echo changeTimeType($seconds);

希望本文所述对大家的PHP程序设计有所帮助。

下面特为大家加点料希望大家能喜欢:

本文汇总了常用的PHP函数,包括获取客户端IP,字符串截取,下载等,详情请查看如下代码:

<?php
/**
 * 获取客户端IP
 * @return [string] [description]
 */
function getClientIp() {
 $ip = NULL;
 if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
  $arr = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
  $pos = array_search('unknown',$arr);
  if(false !== $pos) unset($arr[$pos]);
  $ip = trim($arr[0]);
 }elseif (isset($_SERVER['HTTP_CLIENT_IP'])) {
  $ip = $_SERVER['HTTP_CLIENT_IP'];
 }elseif (isset($_SERVER['REMOTE_ADDR'])) {
  $ip = $_SERVER['REMOTE_ADDR'];
 }
 // IP地址合法验证
 $ip = (false !== ip2long($ip)) ? $ip : '0.0.0.0';
 return $ip;
}

/**
 * 获取在线IP
 * @return String
 */
function getOnlineIp($format=0) {
 global $S_GLOBAL;
 if(empty($S_GLOBAL['onlineip'])) {
  if(getenv('HTTP_CLIENT_IP') && strcasecmp(getenv('HTTP_CLIENT_IP'), 'unknown')) {
   $onlineip = getenv('HTTP_CLIENT_IP');
  } elseif(getenv('HTTP_X_FORWARDED_FOR') && strcasecmp(getenv('HTTP_X_FORWARDED_FOR'), 'unknown')) {
   $onlineip = getenv('HTTP_X_FORWARDED_FOR');
  } elseif(getenv('REMOTE_ADDR') && strcasecmp(getenv('REMOTE_ADDR'), 'unknown')) {
   $onlineip = getenv('REMOTE_ADDR');
  } elseif(isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] && strcasecmp($_SERVER['REMOTE_ADDR'], 'unknown')) {
   $onlineip = $_SERVER['REMOTE_ADDR'];
  }
  preg_match("/[\d\.]{7,15}/", $onlineip, $onlineipmatches);
  $S_GLOBAL['onlineip'] = $onlineipmatches[0] ? $onlineipmatches[0] : 'unknown';
 }

 if($format) {
  $ips = explode('.', $S_GLOBAL['onlineip']);
  for($i=0;$i<3;$i++) {
   $ips[$i] = intval($ips[$i]);
  }
  return sprintf('%03d%03d%03d', $ips[0], $ips[1], $ips[2]);
 } else {
  return $S_GLOBAL['onlineip'];
 }
}



/**
 * 获取url
 * @return [type] [description]
 */
function getUrl(){
 $pageURL = 'http';
 if (isset($_SERVER["HTTPS"]) && $_SERVER["HTTPS"] == "on") {
 $pageURL .= "s";
 }
 $pageURL .= "://";
 if ($_SERVER["SERVER_PORT"] != "80") {
 $pageURL .= $_SERVER["HTTP_HOST"] . ":" . $_SERVER["SERVER_PORT"] . $_SERVER["REQUEST_URI"];
 } else {
 $pageURL .= $_SERVER["HTTP_HOST"] . $_SERVER["REQUEST_URI"];
 }
 return $pageURL;
}

/**
 * 获取当前站点的访问路径根目录
 * @return [type] [description]
 */
function getSiteUrl() {
 $uri = $_SERVER['REQUEST_URI']?$_SERVER['REQUEST_URI']:($_SERVER['PHP_SELF']?$_SERVER['PHP_SELF']:$_SERVER['SCRIPT_NAME']);
 return 'http://'.$_SERVER['HTTP_HOST'].substr($uri, 0, strrpos($uri, '/')+1);
}



/**
 * 字符串截取,支持中文和其他编码
 * @param [string] $str  [字符串]
 * @param integer $start [起始位置]
 * @param integer $length [截取长度]
 * @param string $charset [字符串编码]
 * @param boolean $suffix [是否有省略号]
 * @return [type]   [description]
 */
function msubstr($str, $start=0, $length=15, $charset="utf-8", $suffix=true) {
 if(function_exists("mb_substr")) {
  return mb_substr($str, $start, $length, $charset);
 } elseif(function_exists('iconv_substr')) {
  return iconv_substr($str,$start,$length,$charset);
 }
 $re['utf-8'] = "/[\x01-\x7f]|[\xc2-\xdf][\x80-\xbf]|[\xe0-\xef][\x80-\xbf]{2}|[\xf0-\xff][\x80-\xbf]{3}/";
 $re['gb2312'] = "/[\x01-\x7f]|[\xb0-\xf7][\xa0-\xfe]/";
 $re['gbk'] = "/[\x01-\x7f]|[\x81-\xfe][\x40-\xfe]/";
 $re['big5'] = "/[\x01-\x7f]|[\x81-\xfe]([\x40-\x7e]|\xa1-\xfe])/";
 preg_match_all($re[$charset], $str, $match);
 $slice = join("",array_slice($match[0], $start, $length));
 if($suffix) {
  return $slice."…";
 }
 return $slice;
}

/**
 * php 实现js escape 函数
 * @param [type] $string [description]
 * @param string $encoding [description]
 * @return [type]   [description]
 */
function escape($string, $encoding = 'UTF-8'){
 $return = null;
 for ($x = 0; $x < mb_strlen($string, $encoding);$x ++)
 {
 $str = mb_substr($string, $x, 1, $encoding);
 if (strlen($str) > 1) { // 多字节字符
  $return .= "%u" . strtoupper(bin2hex(mb_convert_encoding($str, 'UCS-2', $encoding)));
 } else {
  $return .= "%" . strtoupper(bin2hex($str));
 }
 }
 return $return;
}
/**
 * php 实现 js unescape函数
 * @param [type] $str [description]
 * @return [type]  [description]
 */
function unescape($str) {
 $str = rawurldecode($str);
 preg_match_all("/(?:%u.{4})|.{4};|&#\d+;|.+/U",$str,$r);
 $ar = $r[0];
 foreach($ar as $k=>$v) {
  if(substr($v,0,2) == "%u"){
   $ar[$k] = iconv("UCS-2","utf-8//IGNORE",pack("H4",substr($v,-4)));
  } elseif(substr($v,0,3) == "") {
   $ar[$k] = iconv("UCS-2","utf-8",pack("H4",substr($v,3,-1)));
  } elseif(substr($v,0,2) == "&#") {
   echo substr($v,2,-1)."";
   $ar[$k] = iconv("UCS-2","utf-8",pack("n",substr($v,2,-1)));
  }
 }
 return join("",$ar);
}

/**
 * 数字转人名币
 * @param [type] $num [description]
 * @return [type]  [description]
 */
function num2rmb ($num) {
 $c1 = "零壹贰叁肆伍陆柒捌玖";
 $c2 = "分角元拾佰仟万拾佰仟亿";
 $num = round($num, 2);
 $num = $num * 100;
 if (strlen($num) > 10) {
  return "oh,sorry,the number is too long!";
 }
 $i = 0;
 $c = "";
 while (1) {
  if ($i == 0) {
   $n = substr($num, strlen($num)-1, 1);
  } else {
   $n = $num % 10;
  }
  $p1 = substr($c1, 3 * $n, 3);
  $p2 = substr($c2, 3 * $i, 3);
  if ($n != '0' || ($n == '0' && ($p2 == '亿' || $p2 == '万' || $p2 == '元'))) {
   $c = $p1 . $p2 . $c;
  } else {
   $c = $p1 . $c;
  }
  $i = $i + 1;
  $num = $num / 10;
  $num = (int)$num;
  if ($num == 0) {
   break;
  }
 }
 $j = 0;
 $slen = strlen($c);
 while ($j < $slen) {
  $m = substr($c, $j, 6);
  if ($m == '零元' || $m == '零万' || $m == '零亿' || $m == '零零') {
   $left = substr($c, 0, $j);
   $right = substr($c, $j + 3);
   $c = $left . $right;
   $j = $j-3;
   $slen = $slen-3;
  }
  $j = $j + 3;
 }
 if (substr($c, strlen($c)-3, 3) == '零') {
  $c = substr($c, 0, strlen($c)-3);
 } // if there is a '0' on the end , chop it out
 return $c . "整";
}

/**
 * 特殊的字符
 * @param [type] $str [description]
 * @return [type]  [description]
 */
function makeSemiangle($str) {
 $arr = array(
  '0' => '0', '1' => '1', '2' => '2', '3' => '3', '4' => '4',
  '5' => '5', '6' => '6', '7' => '7', '8' => '8', '9' => '9',
  'A' => 'A', 'B' => 'B', 'C' => 'C', 'D' => 'D', 'E' => 'E',
  'F' => 'F', 'G' => 'G', 'H' => 'H', 'I' => 'I', 'J' => 'J',
  'K' => 'K', 'L' => 'L', 'M' => 'M', 'N' => 'N', 'O' => 'O',
  'P' => 'P', 'Q' => 'Q', 'R' => 'R', 'S' => 'S', 'T' => 'T',
  'U' => 'U', 'V' => 'V', 'W' => 'W', 'X' => 'X', 'Y' => 'Y',
  'Z' => 'Z', 'a' => 'a', 'b' => 'b', 'c' => 'c', 'd' => 'd',
  'e' => 'e', 'f' => 'f', 'g' => 'g', 'h' => 'h', 'i' => 'i',
  'j' => 'j', 'k' => 'k', 'l' => 'l', 'm' => 'm', 'n' => 'n',
  'o' => 'o', 'p' => 'p', 'q' => 'q', 'r' => 'r', 's' => 's',
  't' => 't', 'u' => 'u', 'v' => 'v', 'w' => 'w', 'x' => 'x',
  'y' => 'y', 'z' => 'z',
  '(' => '(', ')' => ')', '〔' => '[', '〕' => ']', '【' => '[',
  '】' => ']', '〖' => '[', '〗' => ']', '{' => '{', '}' => '}', '《' => '<',
  '》' => '>',
  '%' => '%', '+' => '+', '―' => '-', '-' => '-', '~' => '-',
  ':' => ':', '。' => '.', '、' => ',', ',' => '.', '、' => '.',
  ';' => ';', '?' => '?', '!' => '!', '…' => '-', '‖' => '|',
  '”' => '"', '“' => '"', ''' => '`', '‘' => '`', '|' => '|', '〃' => '"',
  ' ' => ' ','.' => '.');
 return strtr($str, $arr);
}

/**
 * 下载
 * @param [type] $filename [description]
 * @param string $dir  [description]
 * @return [type]   [description]
 */
function downloads($filename,$dir='./'){
 $filepath = $dir.$filename;
 if (!file_exists($filepath)){
  header("Content-type: text/html; charset=utf-8");
  echo "File not found!";
  exit;
 } else {
  $file = fopen($filepath,"r");
  Header("Content-type: application/octet-stream");
  Header("Accept-Ranges: bytes");
  Header("Accept-Length: ".filesize($filepath));
  Header("Content-Disposition: attachment; filename=".$filename);
  echo fread($file, filesize($filepath));
  fclose($file);
 }
}

/**
 * 创建一个目录树
 * @param [type] $dir [description]
 * @param integer $mode [description]
 * @return [type]  [description]
 */
function mkdirs($dir, $mode = 0777) {
 if (!is_dir($dir)) {
  mkdirs(dirname($dir), $mode);
  return mkdir($dir, $mode);
 }
 return true;
}

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