php经过长时间的发展，很多用户都很了解php了，这里我发表一下个人理解，和大家讨论讨论，对php上传文件支持也越来越完美，在php 4.0.3以前我们只能用copy() 和 is_uploaded_file()方法结合来上传文件，呵呵，其实就是这样我们也会感觉到php相对于asp来说上传文件要方便很多，这也就是本人选择php的一点小小的引以为豪的地方。
PHP上传文件例：
<OL class=dp-xml><LI class=alt><SPAN><SPAN>if (!copy($file, $file.’.bak’)) { </SPAN></SPAN><LI class=""><SPAN>print (”failed to copy $file…</SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>br</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN>n”); </SPAN></SPAN><LI class=alt><SPAN>} </SPAN><LI class=""><SPAN>is_uploaded_file(string filename) </SPAN></LI></OL>如果 filename 所给出的文件是通过 HTTP POST 上传的则返回 TRUE。
<OL class=dp-xml><LI class=alt><SPAN><SPAN>move_uploaded_file(string filename, string destination) </SPAN></SPAN></LI></OL>
本函数检查并确保由 filename 指定的文件是合法的PHP上传文件（即通过 PHP 的 HTTP POST 上传机制所上传的）。如果文件合法，则将其移动为由 destination 指定的文件。由三个函数的解释就可以得到一个结论，move_uploaded_file()是copy()和is_uploaded_file()函数的结合，讲了这么半天大家用起这三个函数可能还会有些生疏，下面给大家两个例子：首先，建立一个前台页面，命名为index.html。
立即学习“PHP免费学习笔记（深入）”；
<OL class=dp-xml><LI class=alt><SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>form</SPAN></FONT></STRONG><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>enctype</FONT></SPAN><SPAN>=”multipart/form-data” </SPAN><SPAN class=attribute><FONT color=#ff0000>action</FONT></SPAN><SPAN>=”_URL_” </SPAN><SPAN class=attribute><FONT color=#ff0000>method</FONT></SPAN><SPAN>=”post”</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> </SPAN></SPAN><LI class=""><SPAN>Send this file: </SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>input</SPAN></FONT></STRONG><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>name</FONT></SPAN><SPAN>=”filename” </SPAN><SPAN class=attribute><FONT color=#ff0000>type</FONT></SPAN><SPAN>=”file”</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> </SPAN></SPAN><LI class=alt><SPAN></SPAN><STRONG><FONT color=#006699><SPAN class=tag><</SPAN><SPAN class=tag-name>input</SPAN></FONT></STRONG><SPAN> </SPAN><SPAN class=attribute><FONT color=#ff0000>type</FONT></SPAN><SPAN>=”submit” </SPAN><SPAN class=attribute><FONT color=#ff0000>value</FONT></SPAN><SPAN>=”Send File”</SPAN><SPAN class=tag><STRONG><FONT color=#006699>></FONT></STRONG></SPAN><SPAN> </SPAN></SPAN><LI class=""><SPAN></SPAN><STRONG><FONT color=#006699><SPAN class=tag></</SPAN><SPAN class=tag-name>form</SPAN><SPAN class=tag>></SPAN></FONT></STRONG><SPAN> </SPAN></SPAN></LI></OL>
1,下面是关于copy()和is_uploaded_file()方法上传文件的方法(保存为：copy.php,上传文件需要将index.html中的_URL_改为copy.php)
<OL class=dp-xml><LI class=alt><SPAN><STRONG><FONT color=#006699><SPAN class=tag><?</SPAN><SPAN class=tag-name>php</SPAN></FONT></STRONG><SPAN> </SPAN></SPAN><LI class=""><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>path</FONT></SPAN><SPAN>=”./uploadfiles/”;//上传文件的路径 </SPAN></SPAN><LI class=alt><SPAN>if(is_uploaded_file($filename)) </SPAN><LI class=""><SPAN>//特别注意这里，传递给is_uploaded_file的为$filename,可不要传递$_FILES[”filename”][”name”] </SPAN><LI class=alt><SPAN>{ </SPAN><LI class=""><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>file1</FONT></SPAN><SPAN>=$_FILES[”filename”][”name”]; </SPAN></SPAN><LI class=alt><SPAN>//注意这里$_POST[]方法为PHP4.1.0及以上版本支持,PHP以下的版本要用$HTTP_POST_FILES[]方法 </SPAN><LI class=""><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>file2</FONT></SPAN><SPAN>=$path.time().$file1; </SPAN></SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute><FONT color=#ff0000>flag</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>1</FONT></SPAN><SPAN>; </SPAN></SPAN><LI class=""><SPAN>} </SPAN><LI class=alt><SPAN>if($flag) $</SPAN><SPAN class=attribute><FONT color=#ff0000>result</FONT></SPAN><SPAN>=</SPAN><SPAN class=attribute-value><FONT color=#0000ff>copy</FONT></SPAN><SPAN>($file1,$file2); </SPAN></SPAN><LI class=""><SPAN>if($result) echo “上传成功！”; </SPAN><LI class=alt><SPAN></SPAN><SPAN class=tag><STRONG><FONT color=#006699>?></FONT></STRONG></SPAN><SPAN> </SPAN></SPAN></LI></OL>2,下面是关于move_uploaded_file()方法上传文件的方法(保存为：move.php,上传文件需要将index.html中的_URL_改为move.php)
<OL class=dp-xml><LI class=alt><SPAN><SPAN class=tag><?</SPAN><SPAN class=tag-name>php</SPAN><SPAN> </SPAN></SPAN><LI class=""><SPAN>$</SPAN><SPAN class=attribute>path</SPAN><SPAN>=”./uploadfiles/”;//上传路径 </SPAN></SPAN><LI class=alt><SPAN>if($_FILES[”filename”][”name”]) </SPAN><LI class=""><SPAN>{ </SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute>file1</SPAN><SPAN>=$_FILES[”filename”][”name”]; </SPAN></SPAN><LI class=""><SPAN>$</SPAN><SPAN class=attribute>file2</SPAN><SPAN> = $path.time().$file1; </SPAN></SPAN><LI class=alt><SPAN>$</SPAN><SPAN class=attribute>flag</SPAN><SPAN>=</SPAN><SPAN class=attribute-value>1</SPAN><SPAN>; </SPAN></SPAN><LI class=""><SPAN>} </SPAN><LI class=alt><SPAN>if($flag) $</SPAN><SPAN class=attribute>result</SPAN><SPAN>=</SPAN><SPAN class=attribute-value>move_uploaded_file</SPAN><SPAN>($_FILES[”filename”][”tmp_name”],$file2); </SPAN></SPAN><LI class=""><SPAN>//特别注意这里传递给move_uploaded_file的第一个参数为上传到服务器上的临时文件 </SPAN><LI class=alt><SPAN>if($result) echo “上传成功!”; </SPAN><LI class=""><SPAN></SPAN><SPAN class=tag>?></SPAN><SPAN> </SPAN></SPAN></LI></OL>文件上传就讲到这里了，这只是两个小程序，其实要完成文件上传所要的代码可不是这些就能了事的。一般还要有文件大小限制，文件扩展名选取，还有一些其它的安全方案。本人就写到这了，大家有兴趣写个完善的文件上传系统。呵呵!!!
