用POST方法上传文件

文件上传分为客户端和服务器端

客户端可以通过form表单进行上传

客户端使用html表单进行上传
enctype = "multipart/form-data"用来指定表单编码数据方式
method = "POST"指明发送数据的方法
<form action = "upload.php" method = "POST" enctype = "multipart/form-data">
<input type = "hidden" name = "MAXN_FILIE_SIZE" value = "100000">
选择文件：<input type = "file" name = "myFile">
<input type = "submit" value = "上传文件">
</form>

最主要的就是type="file"的<input>标签

服务器端

 <!--
     简单的文件上传的PHP脚本
 ->
 <?php
     $allowtype = array("gif","png","jpg");
     $size = 1000000;
     $path = "./upload";

     if($_FILES['myfile']['error'] > 0){
         echo "文件上传错误";
         switch($_FILES['myfile']['error']){
             case 1 :die('上传文件大小超过了PHP配置文件中的约定值');
             case 2 :die('上传文件大小超过了浏览器中的约定值');
             case 3 :die('文件只被上传部分');
             case 4 :die('没有上传的文件');
             default :die('其它错误');
         }
     }

     $hz = array_pop(explode(".",$_FILES['myfile']['name']));
     if(!in_array($hz,$allowtype)){
         die("这个后缀是<b>{$hz}</b>不是允许的类型");
     }

     if($_FILES['myfile']['size'] > $size){
         die("超过了允许的<b>$size</b>字节大小");
     }

     $filename = date("YmdHis").rand(100,999).".".$hz;

     if(is_uploaded_file($_FILES['myfile']['tmp_name'])){
         if(!move_uploaded_file($_FILES['myfile']['tmp_name'],$path.'/'.$filename)){
             die("不能将文件移动到指定目录");
         }
     }else{
         die("上传文件：{$_FILES['myfile']['name']}不是一个合法文件");
     }

     echo "文件{$myfile}上传成功，保存在目录{$path}中，大小为{$_FILES['myfile']['size']}字节";
 ?>

用POST方法将文件上传时主要运用到的是$_FILES[]全局数组

$_FILES是一个二维数组 $_FILES['myfile']['name'] $_FILES['myfile']['tmp_name'] $_FILES['myfile']['size'] $_FILES['myfile']['error'] $_FILES['myfile']['type']

用到的函数有：is_uploaded_file()  move_uploaded_file()

多个文件上传时只需要运用myfile[]数组即可 此时的$_FILES是三维数组

 <form action = "upload.php" method = "POST" enctype = "multipart/form-data">
             <input type = "hidden" name = "MAXN_FILIE_SIZE" value = "100000">
             选择文件1：<input type = "file" name = "myFile[]">
             选择文件2：<input type = "file" name = "myFile[]">
             选择文件3：<input type = "file" name = "myFile[]">
             <input type = "submit" value = "上传文件">
         </form>