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php中上传图片

这里来看看php中如何上传图片的

先看代码check_image.php

<html>
    <head>
        <title></title>
        <style type="text/css"></style>
    </head>
    <body>
        <form action="check_image.php" method="post" enctype="multipart/form-data">
            <table>
                <tr>
                    <td>Your username</td>
                    <td><input type="text" name="username" /></td>
                </tr>
                <tr>
                    <td>Upload image*</td>
                    <td><input type="file" name="uploadfile"/></td>
                </tr>
                <tr>
                    <td colspan="2">
                        <small><em> * Acceptable image formats include: GIF, JPG/JPEG and PNG.</em></small>
                    </td>
                </tr>
                <tr>
                    <td>Image Caption</td>
                    <td><input type="text" name="caption"/></td>
                </tr>
                <tr>
                    <td colspan="2" style="text-align:center;">
                        <input type="submit" name="submit" value="Upload" />
                    </td>
                </tr>
            </table>
        </form>
    </body>
</html>

这里没什么可以说的,都是常见的html标签。

下面看看上传的代码check_image.php,重要的地方都做了注释,整个过程是先根据那个<input type="file" name="uploadfile"/>指定的图片路径来创建一个图片文件,然后再通过指定的上传路径生成这个图片。

<?php 
$db = mysql_connect(‘localhost‘,‘root‘,‘Ctrip07185419‘) or die(‘can not connect to database‘);
mysql_select_db(‘moviesite‘,$db) or die(mysql_error($db));
//上传文件的路径
$dir = ‘D:\Serious\phpdev\test\images‘;
/*
$_FILES:用在当需要上传二进制文件的地方,获得该文件的相关信息
$_FILES[‘userfile‘][‘name‘] 客户端机器文件的原名称。 
$_FILES[‘userfile‘][‘type‘] 文件的 MIME 类型,需要浏览器提供该信息的支持,例如“image/gif” 
$_FILES[‘userfile‘][‘size‘] 已上传文件的大小,单位为字节
$_FILES[‘userfile‘][‘tmp_name‘] 文件被上传后在服务端储存的临时文件名,注意不要写成了$_FILES[‘userfile‘][‘temp_name‘]很容易写错的,虽然tmp就是代表临时的意思,但是这里用的缩写
$_FILES[‘userfile‘][‘error‘] 和该文件上传相关的错误代码。[‘error‘] 
*/
if($_FILES[‘uploadfile‘][‘error‘] != UPLOAD_ERR_OK)
{
    switch($_FILES[‘uploadfile‘][‘error‘])
    {
        case UPLOAD_ERR_INI_SIZE: //其值为 1,上传的文件超过了 php.ini 中 upload_max_filesize 选项限制的值
            die(‘The upload file exceeds the upload_max_filesize directive in php.ini‘);
        break;
        case UPLOAD_ERR_FORM_SIZE: //其值为 2,上传文件的大小超过了 HTML 表单中 MAX_FILE_SIZE 选项指定的值
            die(‘The uploaded file exceeds the MAX_FILE_SIZE directive that was specified in the HTML form.‘);
        break;
        case UPLOAD_ERR_PARTIAL: //其值为 3,文件只有部分被上传
            die(‘The uploaded file was only partially uploaded.‘);
        break;
        case UPLOAD_ERR_NO_FILE: //其值为 4,没有文件被上传
            die(‘No file was uploaded.‘);
        break;
        case UPLOAD_ERR_NO_TMP_DIR: //其值为 6,找不到临时文件夹
            die(‘The server is missing a temporary folder.‘);
        break;
        case UPLOAD_ERR_CANT_WRITE: //其值为 7,文件写入失败
            die(‘The server failed to write the uploaded file to disk.‘);
        break;
        case UPLOAD_ERR_EXTENSION: //其他异常
            die(‘File upload stopped by extension.‘);
        break;
    }
}

$image_caption = $_POST[‘caption‘];
$image_username = $_POST[‘username‘];
$image_date = date(‘Y-m-D‘);
/*getimagesize方法返回一个数组,
$width : 索引 0 包含图像宽度的像素值,
$height : 索引 1 包含图像高度的像素值,
$type : 索引 2 是图像类型的标记:
1 = GIF,2 = JPG, 3 = PNG, 4 = SWF, 5 = PSD, 6 = BMP, 
7 = TIFF(intel byte order),8 = TIFF(motorola byte order),
9 = JPC,10 = JP2,11 = JPX,12 = JB2,13 = SWC,14 = IFF,15 = WBMP,16 = XBM,
$attr : 索引 3 是文本字符串,内容为“height="yyy" width="xxx"”,可直接用于 IMG 标记
*/

list($width,$height,$type,$attr) = getimagesize($_FILES[‘uploadfile‘][‘tmp_name‘]);

//imagecreatefromgXXX方法从一个url路径中创建一个新的图片
switch($type)
{
    case IMAGETYPE_GIF:
        $image = imagecreatefromgif($_FILES[‘uploadfile‘][‘tmp_name‘]) or die(‘The file you upload was not supported filetype‘);
        $ext = ‘.gif‘;
    break;
    case IMAGETYPE_JPEG:
        $image = imagecreatefromjpeg($_FILES[‘uploadfile‘][‘tmp_name‘]) or die(‘The file you upload was not supported filetype‘);
        $ext = ‘.jpg‘;
    break;    
    case IMAGETYPE_PNG:
        $image = imagecreatefrompng($_FILES[‘uploadfile‘][‘tmp_name‘]) or die(‘The file you upload was not supported filetype‘);
        $ext = ‘.png‘;
    break;    
    default    :
        die(‘The file you uploaded was not a supported filetype.‘);
}

$query = ‘insert into images(image_caption,image_username,image_date) values ("‘.$image_caption.‘","‘.$image_username.‘",now())‘;
mysql_query($query , $db) or die(mysql_error($db));
$last_id = mysql_insert_id();
//用写入的id作为图片的名字,避免同名的文件存放在同一目录中
$imagename = $last_id.$ext;
$query = ‘update images set image_filename="‘.$imagename.‘" where image_id=‘.$last_id;
mysql_query($query , $db) or die(mysql_error($db));
//有url指定的图片创建图片并保存到指定目录
switch($type)
{
    case IMAGETYPE_GIF:
        imagegif($image,$dir.‘/‘.$imagename);
    break;
    case IMAGETYPE_JPEG:
        imagejpeg($image,$dir.‘/‘.$imagename);
    break;
    case IMAGETYPE_PNG:
        imagepng($image,$dir.‘/‘.$imagename);
    break;
}
//销毁由url生成的图片
imagedestroy($image);
?>

<html>
    <head>
        <title></title>
    </head>
    <body>
        <h1>So how does it feel to be famous</h1>
        <p>Here is the picture you just upload to servers</p>
        <img src="http://www.mamicode.com/images/<?php echo $imagename;?>" alt="upload image" />
        <table>
        <tr>
            <td>Image save as:</td><td><?php echo $imagename?></td>
            <td>Image type:</td><td><?php echo $ext?></td>
            <td>Height:</td><td><?php echo $height?></td>
            <td>Width:</td><td><?php echo $width?></td>
            <td>Upload date:</td><td><?php echo $image_date?></td>
        </tr>
        </table>
    </body>
</html>

最后写道数据库中的信息如下: