PHP判断文件是否存在，可使用如下代码：
<ol class="dp-c">
<li class="alt"><span><span class="comment">//判断远程文件是否存在 </span><span> </span></span></li>
<li>
<span class="keyword">function</span><span> remote_file_exists(</span><span class="vars">$url</span><span>) { </span>
</li>
<li class="alt">
<span> </span><span class="vars">$executeTime</span><span> = </span><span class="func">ini_get</span><span>(</span><span class="string">'max_execution_time'</span><span>); </span>
</li>
<li>
<span> </span><span class="func">ini_set</span><span>(</span><span class="string">'max_execution_time'</span><span>, 0); </span>
</li>
<li class="alt">
<span> </span><span class="vars">$headers</span><span> = @get_headers(</span><span class="vars">$url</span><span>); </span>
</li>
<li>
<span> </span><span class="func">ini_set</span><span>(</span><span class="string">'max_execution_time'</span><span>, </span><span class="vars">$executeTime</span><span>); </span>
</li>
<li class="alt">
<span> </span><span class="keyword">if</span><span> (</span><span class="vars">$headers</span><span>) { </span>
</li>
<li>
<span> </span><span class="vars">$head</span><span> = </span><span class="func">explode</span><span>(</span><span class="string">' '</span><span>, </span><span class="vars">$headers</span><span>[0]); </span>
</li>
<li class="alt">
<span> </span><span class="keyword">if</span><span> (!</span><span class="func">empty</span><span class="keyword">empty</span><span>(</span><span class="vars">$head</span><span>[1]) && </span><span class="func">intval</span><span>(</span><span class="vars">$head</span><span>[1]) <span class="keyword">return</span><span> true; </span></span>
</li>
<li><span> } </span></li>
<li class="alt">
<span> </span><span class="keyword">return</span><span> false; </span>
</li>
<li><span>} </span></li>
</ol>
