12.4.3 處理多個文件上傳

當需要上傳多個文件的情況,有兩種實現的解決方法：
使用不同的表單元素
<input type="file" name="file_a">
<input type="file" name="file_b">
<input type="file" name="file_b">
使用數組格式的表單元素
<input type="file" name="file[]">
<input type="file" name="file[]">
<input type="file" name="file[]">

upform.html

<form action="upload.php" method="post" enctype="multipart/form-data" >
    name: <input type="text" name="username" value="" /><br>
    <input type="hidden" name="MAX_FILE_SIZE" value="1000000" />
    up pic: <input type="file" name="pic[]" value=""><br>
    up pic: <input type="file" name="pic[]" value=""><br>
    up pic: <input type="file" name="pic[]" value=""><br>
    up pic: <input type="file" name="pic[]" value=""><br>

    <input type="submit" value="upload" /><br>

</form> 

upload.php

<?php
header("Content-Type:text/html;charset=utf-8");
/*
Array
(
    [pic] => Array
        (
            [name] => 195_4074_831a070561e20a0.jpg
            [type] => image/jpeg
            [tmp_name] => C:\wamp\tmp\php45.tmp
            [error] => 0
            [size] => 43274
        )

)

[pic] = array(
  [0] => Array
        (
            [name] => 195_4074_831a070561e20a0.jpg
            [type] => image/jpeg
            [tmp_name] => C:\wamp\tmp\php45.tmp
            [error] => 0
            [size] => 43274
    )

  [1] => Array
        (
            [name] => 195_4074_831a070561e20a0.jpg
            [type] => image/jpeg
            [tmp_name] => C:\wamp\tmp\php45.tmp
            [error] => 0
            [size] => 43274
    )

  [2] => Array
        (
            [name] => 195_4074_831a070561e20a0.jpg
            [type] => image/jpeg
            [tmp_name] => C:\wamp\tmp\php45.tmp
            [error] => 0
            [size] => 43274
    )

  [3] => Array
        (
            [name] => 195_4074_831a070561e20a0.jpg
            [type] => image/jpeg
            [tmp_name] => C:\wamp\tmp\php45.tmp
            [error] => 0
            [size] => 43274
    )
    )
 * *
Array
(
    [pic] => Array
        (
            [name] => Array
                (
                    [0] => 175_2426_3ecb275c994a192.jpg
                    [1] => 195_4074_831a070561e20a0.jpg
                    [2] => 46348.jpg
                    [3] => 4e4b68e5a9334.jpg
                )

            [type] => Array
                (
                    [0] => image/jpeg
                    [1] => image/jpeg
                    [2] => image/jpeg
                    [3] => image/jpeg
                )

            [tmp_name] => Array
                (
                    [0] => C:\wamp\tmp\php30.tmp
                    [1] => C:\wamp\tmp\php31.tmp
                    [2] => C:\wamp\tmp\php32.tmp
                    [3] => C:\wamp\tmp\php33.tmp
                )

            [error] => Array
                (
                    [0] => 0
                    [1] => 0
                    [2] => 0
                    [3] => 0
                )

            [size] => Array
                (
                    [0] => 8374
                    [1] => 43274
                    [2] => 4052
                    [3] => 108521
                )

        )

)
 *
 *
 */


$num = count($_FILES['pic']['name']);

for($i=0; $i<$num; $i++) {

    //第一步： 判斷錯誤
    if($_FILES['pic']['error'][$i] > 0) {
        switch($_FILES['pic']['error'][$i]) {
            case 1:
                echo "表示上傳文件的大小超出了約定值。文件大小的最大值是在PHP配置文件中指定的，該指令是：upload_max_filesize<br>";
                break;
            case 2:
                echo "表示上傳文件大小超出了HTML表單隱藏域屬性的MAX＿FILE＿SIZE元素所指定的最大值1M<br>";
                break;
            case 3:
                echo "表示文件只被部分上傳<br>";
                break;
            case 4:
                echo "表示沒有上傳任何文件<br>";
                break;
        
            default:
                echo "末知錯誤<br>";
                
        }
    
        

        continue;
    }

    //第二步： 判斷類型
    $arr = explode(".", basename($_FILES['pic']['name'][$i]));
    $hz = array_pop($arr);
    
    $allowtype =array("gif", "png", "jpg", "jpeg");

    if(!in_array($hz, $allowtype)) {
        echo "上傳的類型不合法";
        continue;
    } 

    //第三步： 判斷大小
    $maxsize= 1000000;
    if($_FILES['pic']['size'][$i] > $maxsize) {
        echo "上傳的文件超過了，{$maxsize}字節!";
        continue;
    }


    //第四步， 上傳后的文件名一定要設置

    $tmpfile = $_FILES['pic']['tmp_name'][$i];
    $srcname = "./uploads/".date("YmdHis").rand(100, 999).".".$hz;

    //將臨時目錄下的上傳的文件，復制到我指定目錄下， 指定的名子就可以完成上傳
    if( move_uploaded_file($tmpfile, $srcname) ) {
        echo "上傳 {$_FILES['pic']['name'][$i]} 成功!<br>";
    }else{
        echo "上傳失敗!<br>";
    }

}