PHP开发的二手回收网站实现用户头像上传功能

<form action="upload.php" method="post" enctype="multipart/form-data">
    <input type="file" name="avatar" id="avatar" accept="image/*">
    <input type="submit" value="上传头像">
</form>

<?php
$targetDir = "uploads/"; // 上传文件存储路径
$targetFile = $targetDir . basename($_FILES["avatar"]["name"]);
$uploadOk = 1;
$imageFileType = strtolower(pathinfo($targetFile,PATHINFO_EXTENSION));

// 检查文件是否是图片格式
if(isset($_POST["submit"])) {
    $check = getimagesize($_FILES["avatar"]["tmp_name"]);
    if($check !== false) {
        echo "文件是图片格式 - " . $check["mime"] . ".";
        $uploadOk = 1;
    } else {
        echo "文件不是图片格式.";
        $uploadOk = 0;
    }
}

// 检查文件大小
if ($_FILES["avatar"]["size"] > 500000) {
    echo "文件过大，不能超过 500KB.";
    $uploadOk = 0;
}

// 允许上传的图片格式
$allowedExtensions = array("jpg", "jpeg", "png", "gif");
if(!in_array($imageFileType, $allowedExtensions)) {
    echo "只允许上传 JPG, JPEG, PNG, 或 GIF 格式的文件.";
    $uploadOk = 0;
}

// 检查上传状态
if ($uploadOk == 0) {
    echo "文件上传失败.";
} else {
    if (move_uploaded_file($_FILES["avatar"]["tmp_name"], $targetFile)) {
        echo "文件上传成功.";
    } else {
        echo "文件上传失败.";
    }
}
?>

<img src="uploads/<?php echo basename($targetFile); ?>" alt="用户头像">