$filename = "/folder/" . $dirname . "/";

if (file_exists($filename)) {
    echo "The directory $dirname exists.";
} else {
    mkdir("folder/" . $dirname, 0755);
    echo "The directory $dirname was successfully created.";
    exit;
}

在Unix系统上，两者都将返回true——在Unix中，所有东西都是一个文件，包括目录。但要测试该名称是否已被占用，您应该同时检查两个名称。可能会有一个名为“foo”的常规文件，这将阻止你创建一个名为“foo”的目录。

$filename = "/folder/" . $dirname . "/";

if (file_exists($filename)) {
    echo "The directory $dirname exists.";
} else {
    mkdir("folder/" . $dirname, 0755);
    echo "The directory $dirname was successfully created.";
    exit;
}

$year = date("Y");   
$month = date("m");   
$filename = "../".$year;   
$filename2 = "../".$year."/".$month;

if(file_exists($filename)){
    if(file_exists($filename2)==false){
        mkdir($filename2,0777);
    }
}else{
    mkdir($filename,0777);
}

我就是这么做的

if(is_dir("./folder/test"))
{
  echo "Exist";
}else{
  echo "Not exist";
}

我认为realpath()可能是验证路径是否存在的最佳方法 http://www.php.net/realpath

下面是一个示例函数:

<?php
/**
 * Checks if a folder exist and return canonicalized absolute pathname (long version)
 * @param string $folder the path being checked.
 * @return mixed returns the canonicalized absolute pathname on success otherwise FALSE is returned
 */
function folder_exist($folder)
{
    // Get canonicalized absolute pathname
    $path = realpath($folder);

    // If it exist, check if it's a directory
    if($path !== false AND is_dir($path))
    {
        // Return canonicalized absolute pathname
        return $path;
    }

    // Path/folder does not exist
    return false;
}

相同函数的简写版本

<?php
/**
 * Checks if a folder exist and return canonicalized absolute pathname (sort version)
 * @param string $folder the path being checked.
 * @return mixed returns the canonicalized absolute pathname on success otherwise FALSE is returned
 */
function folder_exist($folder)
{
    // Get canonicalized absolute pathname
    $path = realpath($folder);

    // If it exist, check if it's a directory
    return ($path !== false AND is_dir($path)) ? $path : false;
}

输出示例

<?php
/** CASE 1 **/
$input = '/some/path/which/does/not/exist';
var_dump($input);               // string(31) "/some/path/which/does/not/exist"
$output = folder_exist($input);
var_dump($output);              // bool(false)

/** CASE 2 **/
$input = '/home';
var_dump($input);
$output = folder_exist($input);         // string(5) "/home"
var_dump($output);              // string(5) "/home"

/** CASE 3 **/
$input = '/home/..';
var_dump($input);               // string(8) "/home/.."
$output = folder_exist($input);
var_dump($output);              // string(1) "/"

使用

<?php

$folder = '/foo/bar';

if(FALSE !== ($path = folder_exist($folder)))
{
    die('Folder ' . $path . ' already exist');
}

mkdir($folder);
// Continue do stuff