PHP文件系统相关函数的功能详解_PHP教程
- WBOY원래의
- 2016-07-15 13:29:441012검색
我们通过对关于文件路径的解释：在Windows中，可以在路径中使用/和符号，而在其他的操作系统中只能使用/符号。出于一致性的缘故，我们统一使用/符号。
下面的PHP文件系统相关函数脚本样例可以显示一个目录清单，注释已经包含在代码中：
<ol class="dp-xml">
<li class="alt"><span><span class="tag"><strong><font color="#006699"></font></strong></span><span> /*把要读取的目录的全路径名存入一个名字为$dir_name的变量中。 */ </span></span></li>
<li class=""><span> </span></li>
<li class="alt">
<span>$</span><span class="attribute"><font color="#ff0000">dir_name</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">"/home/me/"</font></span><span>; </span>
</li>
<li class=""><span> </span></li>
<li class="alt"><span>/* 创建一个句柄，其值是打开一个给定目录的结果*/ </span></li>
<li class=""><span> </span></li>
<li class="alt">
<span>$</span><span class="attribute"><font color="#ff0000">dir</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">opendir</font></span><span>($dir_name); </span>
</li>
<li class=""><span> </span></li>
<li class="alt"><span>/* 建立一个文字块，用以放置列表元素（文件名字）*/ </span></li>
<li class=""><span> </span></li>
<li class="alt">
<span>$</span><span class="attribute"><font color="#ff0000">file_list</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">"<ul>"</ul></font></span><span>; </span>
</li>
<li class=""><span> </span></li>
<li class="alt"><span>/* 使用一个while语句，读取已经打开的目录中的所有元素，如果文件的名字不是“.”或“..”，则显示列表中的名字*/ </span></li>
<li class=""><span> </span></li>
<li class="alt">
<span>while ($</span><span class="attribute"><font color="#ff0000">file_name</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">readdir</font></span><span>($dir)) { </span>
</li>
<li class=""><span> </span></li>
<li class="alt"><span>if (($file_name != ".") && ($file_name != "..")) { </span></li>
<li class=""><span> </span></li>
<li class="alt">
<span>$file_list </span><span class="attribute"><font color="#ff0000">.</font></span><span>= </span><span class="attribute-value"><font color="#0000ff">"<li>$file_name"</li></font></span><span>; </span>
</li>
<li class=""><span> </span></li>
<li class="alt"><span>} </span></li>
<li class=""><span> </span></li>
<li class="alt"><span>} </span></li>
<li class=""><span> </span></li>
<li class="alt">
<span>$file_list </span><span class="attribute"><font color="#ff0000">.</font></span><span>= </span><span class="attribute-value"><font color="#0000ff">""</font></span><span>; </span>
</li>
<li class=""><span> </span></li>
<li class="alt"><span>/*关闭打开的目录，结束PHP模块*/ </span></li>
<li class=""><span> </span></li>
<li class="alt"><span>closedir($dir); </span></li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><span class="comments"><font color="#008200"><!-- Start your HTML --></font></span><span> </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">HTML</span><span class="tag">></span></span></font></strong><span> </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">HEAD</span><span class="tag">></span></span></font></strong><span> </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">TITLE</span><span class="tag">></span></span></font></strong><span>Directory Listing</span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">TITLE</span><span class="tag">></span></font></strong><span> </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">HEAD</span><span class="tag">></span></font></strong><span> </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">BODY</span><span class="tag">></span></span></font></strong><span> </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><span class="comments"><font color="#008200"><!-- Use PHP to print the name of the directory you read --></font></span><span> </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"><span class="tag-name">P</span><span class="tag">></span></span></font></strong><span>Files in: </span><span class="tag"><strong><font color="#006699"></font></strong></span><span> </span><span class="tag-name"><strong><font color="#006699">echo</font></strong></span><span> "$dir_name"; </span><strong><font color="#006699"><span class="tag">?></span><span class="tag"></span><span class="tag-name">p</span><span class="tag">></span></font></strong><span> </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><span class="comments"><font color="#008200"><!-- Use PHP to print the directory listing --></font></span><span> </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699"></font></strong></span><span> </span><span class="tag-name"><strong><font color="#006699">echo</font></strong></span><span> "$file_list"; </span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">BODY</span><span class="tag">></span></font></strong><span> </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><strong><font color="#006699"><span class="tag"></span><span class="tag-name">HTML</span><span class="tag">></span></font></strong><span> </span>
</li>
</ol>
好了，我们已经得到了一个目录清单。需要注意的是，要读取一个文件（稍后我们将进行讲解）或目录的内容，PHP运行的系统上的用户必须至少有读取文件的权限。
下面是一个如何拷贝文件的PHP文件系统相关函数例子：
<ol class="dp-xml">
<li class="alt"><span><span class="tag"><strong><font color="#006699"></font></strong></span><span> /*把你要拷贝的原文件的全路径赋给一个名字为$original的变量中，把拷贝的文件的全路径赋予一个名字为$copied的变量中*/ </span></span></li>
<li class=""><span> </span></li>
<li class="alt">
<span>$</span><span class="attribute"><font color="#ff0000">original</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">"/home/me/mydatabasedump"</font></span><span>; </span>
</li>
<li class=""><span> </span></li>
<li class="alt">
<span>$</span><span class="attribute"><font color="#ff0000">copied</font></span><span> = </span><span class="attribute-value"><font color="#0000ff">"/archive/mydatabasedumo_1010"</font></span><span>; </span>
</li>
<li class=""><span> </span></li>
<li class="alt"><span>/* 使用copy()函数拷贝原始文件，如果拷贝没有完成则会显示一个错误信息*/ </span></li>
<li class=""><span> </span></li>
<li class="alt"><span>@copy($original, $copied) or die("Couldn't copy file."); </span></li>
<li class=""><span> </span></li>
<li class="alt">
<span></span><span class="tag"><strong><font color="#006699">?></font></strong></span><span> </span>
</li>
</ol>
这个PHP文件系统相关函数的例子是一个文件备份系统的原型。在这段脚本运行时，它把文件拷贝到一个不同的位置进行保存。稍微修改一下守护程序，就可以在一天中你指定的时刻执行它，而无需用户的干预。
假定你在系统上安装了Lynx，可以创建一个守护程序的条目访问这个文件，访问这个文件会运行这个脚本并建立一个拷贝文件，下面的例子将在上午5点钟运行这个脚本，然后关闭Lynx：
0 5 * * * [username] lynx -dump http://localhost/copyfile.php 1>/dev/null 2>&1
如果运行的是CGI版本的PHP，可以跳过Lynx部分，而直接调用二进制文件：
0 5 * * * [username] php /path/to/copyfile.php 1>/dev/null 2>&1
성명：
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