详细介绍PHP的目录操作和文件操作

关于PHP中的目录操作和文件操作，也曾介绍过，不过有的人还是不是很明白。下面详细介绍PHP的目录操作和文件操作。

在任何计算机设备中,文件是都是必须的对象,而在Web编程中,文件的操作一直是web程序员的头疼的地方,而,文件的操作在cms系统中这是必须的,非常有用的,我们经常遇到生成文件目录,文件(夹)编辑等操作,现在我把PHP中的这些函数做一详细总结并实例示范如何使用.,关于对应的函数详细介绍,请查阅php手册.此处只总结重点.和需要注意的地方.(这在php手册是没有的.)

一、目录操作

首先介绍的是一个从目录读取的函数,opendir(),readdir(),closedir(),使用的时候是先打开文件句柄,而后迭代列出:

<ol class="dp-c">
<li class="alt"><span><span><?php    </span></span></span></li>
<li>
<span class="vars">$base_dir</span><span> = </span><span class="string">"filelist/"</span><span>;   </span>
</li>
<li class="alt">
<span class="vars">$fso</span><span> = opendir(</span><span class="vars">$base_dir</span><span>);   </span>
</li>
<li>
<span class="func">echo</span><span> </span><span class="vars">$base_dir</span><span>."  </span>
</li>
<li class="alt"><span> </span></li>
<li><span>" ;   </span></li>
<li class="alt">
<span class="keyword">while</span><span>(</span><span class="vars">$flist</span><span>=readdir(</span><span class="vars">$fso</span><span>)){   </span>
</li>
<li>
<span class="func">echo</span><span> </span><span class="vars">$flist</span><span>."   </span>
</li>
<li class="alt"><span>" ;   </span></li>
<li><span>}   </span></li>
<li class="alt">
<span class="func">closedir</span><span>(</span><span class="vars">$fso</span><span>)   </span>
</li>
<li><span>?> </span></li>
</ol>

这是讲返回文件目录下面的文件已经目录的程序(0文件将返回false).

有时候需要知道目录的信息,可以使用dirname($path)和basename($path),分别返回路径的目录部分和文件名名称部分,可用disk_free_space($path)返回看空间空余空间.

创建命令:

mkdir($path,0777),0777是权限码,在非window下可用umask()函数设置rmdir($path)

将删除路径在$path的文件.

dir -- directory 类也是操作文件目录的重要类,有3个方法,read,rewind,close,这是一个仿面向对象的类,它先使用的是打开文件句柄,然后用指针的方式读取的.,这里看php手册:

<ol class="dp-c">
<li class="alt"><span><span><?php    </span></span></span></li>
<li>
<span class="vars">$d</span><span> = dir(</span><span class="string">"/etc/php5"</span><span>);   </span>
</li>
<li class="alt">
<span class="func">echo</span><span> </span><span class="string">"Handle: "</span><span> . </span><span class="vars">$d</span><span>->handle . </span><span class="string">"n"</span><span>;   </span>
</li>
<li>
<span class="func">echo</span><span> </span><span class="string">"Path: "</span><span> . </span><span class="vars">$d</span><span>->path . </span><span class="string">"n"</span><span>;   </span>
</li>
<li class="alt">
<span class="keyword">while</span><span> (false !== (</span><span class="vars">$entry</span><span> = </span><span class="vars">$d</span><span>->read())) {   </span>
</li>
<li>
<span class="func">echo</span><span> </span><span class="vars">$entry</span><span>.</span><span class="string">"n"</span><span>;   </span>
</li>
<li class="alt"><span>}   </span></li>
<li>
<span class="vars">$d</span><span>->close();   </span>
</li>
<li class="alt"><span>?> </span></li>
</ol> 

输出:

<ol class="dp-xml">
<li class="alt"><span><span>Handle: Resource id #2   </span></span></li>
<li><span>Path: /etc/php5   </span></li>
<li class="alt"><span>.   </span></li>
<li><span>..   </span></li>
<li class="alt"><span>apache   </span></li>
<li><span>CGI   </span></li>
<li class="alt"><span>cli </span></li>
</ol>

文件的属性也非常重要,文件属性包括创建时间,最后修改时间,所有者,文件组,类型,大小等.

下面我们重点谈文件操作.

二、文件操作

A、读文件

首先是一个文件看能不能读取(权限问题),或者存在不,我们可以用is_readable函数获取信息。

<ol class="dp-c">
<li class="alt"><span><span><?php    </span></span></span></li>
<li>
<span class="vars">$file</span><span> = </span><span class="string">'dirlist.php'</span><span>;   </span>
</li>
<li class="alt">
<span class="keyword">if</span><span> (</span><span class="func">is_readable</span><span>(</span><span class="vars">$file</span><span>) == false) {   </span>
</li>
<li>
<span class="keyword">die</span><span>(</span><span class="string">'文件不存在或者无法读取'</span><span>);   </span>
</li>
<li class="alt">
<span>} </span><span class="keyword">else</span><span> {   </span>
</li>
<li>
<span class="func">echo</span><span> </span><span class="string">'存在'</span><span>;   </span>
</li>
<li class="alt"><span>}   </span></li>
<li><span>?> </span></li>
</ol>

判断文件存在的函数还有file_exists(下面演示),但是这个显然无is_readable全面.,当一个文件存在的话可以用

<ol class="dp-c">
<li class="alt"><span><span><?php    </span></span></span></li>
<li>
<span class="vars">$file</span><span> = </span><span class="string">"filelist.php"</span><span>;   </span>
</li>
<li class="alt">
<span class="keyword">if</span><span> (</span><span class="func">file_exists</span><span>(</span><span class="vars">$file</span><span>) == false) {   </span>
</li>
<li>
<span class="keyword">die</span><span>(</span><span class="string">'文件不存在'</span><span>);   </span>
</li>
<li class="alt"><span>}   </span></li>
<li>
<span class="vars">$data</span><span> = </span><span class="func">file_get_contents</span><span>(</span><span class="vars">$file</span><span>);   </span>
</li>
<li class="alt">
<span class="func">echo</span><span> htmlentities(</span><span class="vars">$data</span><span>);   </span>
</li>
<li><span>?> </span></li>
</ol>

但是file_get_contents函数在较低版本上不支持,可以先创建文件的一个句柄,然后用指针读取全部:

<ol class="dp-c">
<li class="alt"><span><span class="vars">$fso</span><span> = </span><span class="func">fopen</span><span>(</span><span class="vars">$cacheFile</span><span>, </span><span class="string">'r'</span><span>);   </span></span></li>
<li>
<span class="vars">$data</span><span> = </span><span class="func">fread</span><span>(</span><span class="vars">$fso</span><span>, </span><span class="func">filesize</span><span>(</span><span class="vars">$cacheFile</span><span>));   </span>
</li>
<li class="alt">
<span>fclose(</span><span class="vars">$fso</span><span>); </span>
</li>
</ol>

还有一种方式,可以读取二进制的文件:

<ol class="dp-c"><li class="alt"><span><span class="vars">$data</span><span> = implode(</span><span class="string">''</span><span>, file(</span><span class="vars">$file</span><span>)); </span></span></li></ol>

B、写文件

和读取文件的方式一样,先看看是不是能写:

<ol class="dp-c">
<li class="alt"><span><span>　<?php    </span></span></span></li>
<li>
<span class="vars">$file</span><span> = </span><span class="string">'dirlist.php'</span><span>;   </span>
</li>
<li class="alt">
<span class="keyword">if</span><span> (</span><span class="func">is_writable</span><span>(</span><span class="vars">$file</span><span>) == false) {   </span>
</li>
<li>
<span class="keyword">die</span><span>(</span><span class="string">"我是鸡毛,我不能"</span><span>);   </span>
</li>
<li class="alt"><span>}   </span></li>
<li><span>?> </span></li>
</ol>

能写了的话可以使用file_put_contents函数写入

<ol class="dp-c">
<li class="alt"><span><span><?php    </span></span></span></li>
<li>
<span class="vars">$file</span><span> = </span><span class="string">'dirlist.php'</span><span>;   </span>
</li>
<li class="alt">
<span class="keyword">if</span><span> (</span><span class="func">is_writable</span><span>(</span><span class="vars">$file</span><span>) == false) {   </span>
</li>
<li>
<span class="keyword">die</span><span>(</span><span class="string">'我是鸡毛,我不能'</span><span>);   </span>
</li>
<li class="alt"><span>}   </span></li>
<li>
<span class="vars">$data</span><span> = </span><span class="string">'我是可鄙,我想要'</span><span>;   </span>
</li>
<li class="alt">
<span class="func">file_put_contents</span><span> (</span><span class="vars">$file</span><span>, </span><span class="vars">$data</span><span>);   </span>
</li>
<li><span>?> </span></li>
</ol>

file_put_contents函数在php5中新引进的函数(不知道存在的话用function_exists函数先判断一下)低版本的php无法使用,可以使用如下方式:

<ol class="dp-c">
<li class="alt"><span><span class="vars">$f</span><span> = </span><span class="func">fopen</span><span>(</span><span class="vars">$file</span><span>, </span><span class="string">'w'</span><span>);   </span></span></li>
<li>
<span>fwrite(</span><span class="vars">$f</span><span>, </span><span class="vars">$data</span><span>);   </span>
</li>
<li class="alt">
<span>fclose(</span><span class="vars">$f</span><span>); </span>
</li>
</ol>

替换之.

写文件的时候有时候需要锁定,然后写:

<ol class="dp-c">
<li class="alt"><span><span class="keyword">function</span><span> cache_page(</span><span class="vars">$pageurl</span><span>,</span><span class="vars">$pagedata</span><span>){   </span></span></li>
<li>
<span class="keyword">if</span><span>(!</span><span class="vars">$fso</span><span>=</span><span class="func">fopen</span><span>(</span><span class="vars">$pageurl</span><span>,</span><span class="string">'w'</span><span>)){   </span>
</li>
<li class="alt">
<span class="vars">$this</span><span>->warns(</span><span class="string">'无法打开缓存文件.'</span><span>);</span><span class="comment">//trigger_error  </span><span> </span>
</li>
<li>
<span class="keyword">return</span><span> false;   </span>
</li>
<li class="alt"><span>}   </span></li>
<li>
<span class="keyword">if</span><span>(!</span><span class="func">flock</span><span>(</span><span class="vars">$fso</span><span>,LOCK_EX)){</span><span class="comment">//LOCK_NB,排它型锁定  </span><span> </span>
</li>
<li class="alt">
<span class="vars">$this</span><span>->warns(</span><span class="string">'无法锁定缓存文件.'</span><span>);</span><span class="comment">//trigger_error  </span><span> </span>
</li>
<li>
<span class="keyword">return</span><span> false;   </span>
</li>
<li class="alt"><span>}   </span></li>
<li>
<span class="keyword">if</span><span>(!fwrite(</span><span class="vars">$fso</span><span>,</span><span class="vars">$pagedata</span><span>)){</span><span class="comment">//写入字节流,serialize写入其他格式  </span><span> </span>
</li>
<li class="alt">
<span class="vars">$this</span><span>->warns(</span><span class="string">'无法写入缓存文件.'</span><span>);</span><span class="comment">//trigger_error  </span><span> </span>
</li>
<li>
<span class="keyword">return</span><span> false;   </span>
</li>
<li class="alt"><span>}   </span></li>
<li>
<span class="func">flock</span><span>(</span><span class="vars">$fso</span><span>,LOCK_UN);</span><span class="comment">//释放锁定  </span><span> </span>
</li>
<li class="alt">
<span>fclose(</span><span class="vars">$fso</span><span>);   </span>
</li>
<li>
<span class="keyword">return</span><span> true;   </span>
</li>
<li class="alt"><span>} </span></li>
</ol>

C、复制,删除文件

php删除文件非常easy,用unlink函数简单操作:

<ol class="dp-c">
<li class="alt"><span><span><?php    </span></span></span></li>
<li>
<span class="vars">$file</span><span> = </span><span class="string">'dirlist.php'</span><span>;   </span>
</li>
<li class="alt">
<span class="vars">$result</span><span> = @unlink (</span><span class="vars">$file</span><span>);   </span>
</li>
<li>
<span class="keyword">if</span><span> (</span><span class="vars">$result</span><span> == false) {   </span>
</li>
<li class="alt">
<span class="func">echo</span><span> </span><span class="string">'蚊子赶走了'</span><span>;   </span>
</li>
<li>
<span>} </span><span class="keyword">else</span><span> {   </span>
</li>
<li class="alt">
<span class="func">echo</span><span> </span><span class="string">'无法赶走'</span><span>;   </span>
</li>
<li><span>}   </span></li>
<li class="alt"><span>?> </span></li>
</ol>

即可.

复制文件也很容易:

<ol class="dp-c">
<li class="alt"><span><span><?php    </span></span></span></li>
<li>
<span class="vars">$file</span><span> = </span><span class="string">'yang.txt'</span><span>;   </span>
</li>
<li class="alt">
<span class="vars">$newfile</span><span> = </span><span class="string">'ji.txt'</span><span>; # 这个文件父文件夹必须能写   </span>
</li>
<li>
<span class="keyword">if</span><span> (</span><span class="func">file_exists</span><span>(</span><span class="vars">$file</span><span>) == false) {   </span>
</li>
<li class="alt">
<span class="keyword">die</span><span> (</span><span class="string">'小样没上线,无法复制'</span><span>);   </span>
</li>
<li><span>}   </span></li>
<li class="alt">
<span class="vars">$result</span><span> = </span><span class="func">copy</span><span>(</span><span class="vars">$file</span><span>, </span><span class="vars">$newfile</span><span>);   </span>
</li>
<li>
<span class="keyword">if</span><span> (</span><span class="vars">$result</span><span> == false) {   </span>
</li>
<li class="alt">
<span class="func">echo</span><span> </span><span class="string">'复制记忆ok'</span><span>;   </span>
</li>
<li><span>}   </span></li>
<li class="alt"><span>?> </span></li>
</ol>

可以使用rename()函数重命名一个文件夹.其他操作都是这几个函数组合一下就能实现的.

D、获取文件属性

我说几个常见的函数:

获取最近修改时间:

<ol class="dp-c">
<li class="alt"><span><span><?php    </span></span></span></li>
<li>
<span class="vars">$file</span><span> = </span><span class="string">'test.txt'</span><span>;   </span>
</li>
<li class="alt">
<span class="func">echo</span><span> </span><span class="func">date</span><span>(</span><span class="string">'r'</span><span>, </span><span class="func">filemtime</span><span>(</span><span class="vars">$file</span><span>));   </span>
</li>
<li><span>?> </span></li>
</ol>

返回的说Unix的时间戳,这在缓存技术常用.

相关的还有获取上次被访问的时间fileatime(),filectime()当文件的权限，所有者，所有组或其它 inode 中的元数据被更新时间,fileowner()函数返回文件所有者

<ol class="dp-c"><li class="alt"><span><span class="vars">$owner</span><span> = posix_getpwuid(</span><span class="func">fileowner</span><span>(</span><span class="vars">$file</span><span>)); </span></span></li></ol>

(非window系统),ileperms()获取文件的权限,

<ol class="dp-c">
<li class="alt"><span><span><?php    </span></span></span></li>
<li>
<span class="vars">$file</span><span> = </span><span class="string">'dirlist.php'</span><span>;   </span>
</li>
<li class="alt">
<span class="vars">$perms</span><span> = </span><span class="func">substr</span><span>(sprintf(</span><span class="string">'%o'</span><span>, </span><span class="func">fileperms</span><span>(</span><span class="vars">$file</span><span>)), -4);   </span>
</li>
<li>
<span class="func">echo</span><span> </span><span class="vars">$perms</span><span>;   </span>
</li>
<li class="alt"><span>?> </span></li>
</ol>

filesize()返回文件大小的字节数:

<ol class="dp-c">
<li class="alt"><span><span><?php    </span></span></span></li>
<li>
<span class="comment">// 输出类似：somefile.txt: 1024 bytes  </span><span> </span>
</li>
<li class="alt">
<span class="vars">$filename</span><span> = </span><span class="string">'somefile.txt'</span><span>;   </span>
</li>
<li>
<span class="func">echo</span><span> </span><span class="vars">$filename</span><span> . </span><span class="string">': '</span><span> . </span><span class="func">filesize</span><span>(</span><span class="vars">$filename</span><span>) . </span><span class="string">' bytes'</span><span>;   </span>
</li>
<li class="alt"><span>?> </span></li>
</ol>

获取文件的全部信息有个返回数组的函数stat()函数:

<ol class="dp-c">
<li class="alt"><span><span><?php    </span></span></span></li>
<li>
<span class="vars">$file</span><span> = </span><span class="string">'dirlist.php'</span><span>;   </span>
</li>
<li class="alt">
<span class="vars">$perms</span><span> = stat(</span><span class="vars">$file</span><span>);   </span>
</li>
<li>
<span>var_dump(</span><span class="vars">$perms</span><span>);   </span>
</li>
<li class="alt"><span>?> </span></li>
</ol>

那个键对应什么可以查阅详细资料,此处不再展开.

四、结束语

上面我简要的总结了一下几个文件操作,如果您熟练掌握以上列出的函数,已经在操作的时候没什么大的问题,php文件操作的函数变化比较快,现在已经非常强大了,文件这部分也是学习php非常重要的一部分,希望不要忽略.