php 上传图片易名

php 上传图片改名
从网上找了一段上传 图片代码，然后想把上传的图片名改成用户名+图片后缀（用户名为$user,)但是没看懂这段代码，所以不知道怎么弄，请各位指点

$user="hah";
$targetFolder = '/uploads'; // Relative to the root

if (!empty($_FILES)) {
	$tempFile = $_FILES['userfile']['tmp_name']; //
	$targetPath = $_SERVER['DOCUMENT_ROOT'] . $targetFolder;
	$targetFile = rtrim($targetPath,'//m.sbmmt.com/m/') . '//m.sbmmt.com/m/' . $_FILES['userfile']['name'];



	$fileTypes = array('jpg','jpeg','gif','png'); // File extensions
	$fileParts = pathinfo($_FILES['userfile']['name']);

	if (in_array($fileParts['extension'],$fileTypes)) {
		$arr = getimagesize($tempFile);
         


		move_uploaded_file( $tempFile,$targetFile);
		$data = array(
				"state" => '00',
				"desc"  => 	'ok',
				"src"   => "http://localhost/uploads/".$_FILES['userfile']['name'],
				"touxiang"  => 	$touxiangs,
		);


		echo json_encode($data);
	} else {
		echo 'Invalid file type.';
	}
}

------解决方案--------------------
修改第7行
$targetFile = rtrim($targetPath,'//m.sbmmt.com/m/') . '//m.sbmmt.com/m/' . $_FILES['userfile']['name'];

------解决方案--------------------
$targetFile = $targetPath . '//m.sbmmt.com/m/' . $user . '.' . pathinfo($_FILES['userfile']['name'], PATHINFO_EXTENSION);
------解决方案--------------------

$user="hah";
$targetFolder = '/uploads'; // Relative to the root

if (!empty($_FILES)) {
	$tempFile = $_FILES['userfile']['tmp_name']; //
	$targetPath = $_SERVER['DOCUMENT_ROOT'] . $targetFolder;


	$fileTypes = array('jpg','jpeg','gif','png'); // File extensions
	$fileParts = pathinfo($_FILES['userfile']['name']);

	$targetFile = rtrim($targetPath,'//m.sbmmt.com/m/') . '//m.sbmmt.com/m/' . $user . '.' .$fileParts['extension'];
	if (in_array($fileParts['extension'],$fileTypes)) {
		$arr = getimagesize($tempFile);
         


		move_uploaded_file( $tempFile,$targetFile);
		$data = array(
				"state" => '00',
				"desc"  => 	'ok',
				"src"   => "http://localhost/uploads/".$user . '.' .$fileParts['extension'],
				"touxiang"  => 	$touxiangs,
		);


		echo json_encode($data);
	} else {
		echo 'Invalid file type.';
	}
}





?>