php处理上传图片的步骤

<?php

header("content-type:text/html;charset=utf-8");

$allowType=array('jpg','gif','png','jpeg');

$maxsize=5000000;

if($_POST['sub']){

if($_FILES["spic"]["error"] > 0){

switch($_FILES["pic"]["error"]) {

case 1:

echo "上传的文件超过了 php.ini 中 upload_max_filesize 选项限制的值<br>";

break;

case 2:

echo "上传文件的大小超过了 HTML 表单中 MAX_FILE_SIZE 选项指定的值";

break;

case 3:

echo "文件只有部分被上传";

break;

case 4:

echo "没有文件被上传";

break;

default:

echo "末知错误";

}

exit;

}

$strArr=explode('.',$_FILES['spic']['name']);

$hz=$strArr[count($strArr)-1];

if(!in_array($hz,$allowType)){

exit("上传文件类型不正确.");

}

if($_FILES['spic']['size']>$maxsize){

exit("上传文件大小不能超过".$maxsize."字节.");

}

$fileName='./upload/';

if(!file_exists($fileName) || !is_writable($fileName)){

if(!@mkdir($fileName,0755)){

echo "建立上传目录失败，请重新指定上传目录";

}

}

if(is_uploaded_file($_FILES['spic']['tmp_name'])){

if(@move_uploaded_file($_FILES['spic']['tmp_name'],$fileName.$_FILES['spic']['name'])){

echo "上传文件成功";

}else{

echo "上传文件失败";

}

}else{

echo "非上传文件";

}

}