本例将设计一个具体文件操作界面，允许用户删除指定目录下的所有文本文件，运行结果如图11.17所示。
图11.17 管理指定类型文件
【操作步骤】
第1步，创建index.php，设计一个表格，遍历当前目录所有文件。删除指定目录下特定格式文件的实现原理与删除所有文件相同，只是在创建删除链接前对文件的格式进行判断，如果文件是.txt类型，那么就输出删除的超链接，否则将直接输出文件的名称。
<table>
<tr>
<th>项目名</th>
<th>大小</th>
<th>创建日期</th>
<th>最后修改时间</th>
<th>操作</th>
</tr>
<?php
if (! isset ( $_GET ['catalog'] ) || empty ( $_GET ['catalog'] ))
$current_directory = getcwd (); //获得脚本目录
else
$current_directory = $_GET ['catalog'];
chdir ( iconv ( "utf-8", "gb2312", $current_directory ) ); //改变当前目录
echo "<span class='STYLE4'>当前目录:</span><span class='STYLE2'>" . iconv ( "gb2312", "utf-8", getcwd () ) . "</span><hr>";
$ml = opendir ( iconv ( "utf-8", "gb2312", $current_directory ) ); //打开目录
$php_self = $_SERVER['PHP_SELF'];
while ( $gain_directory = readdir ( $ml ) ) { //循环读取目录中的目录及文件
echo "<tr><td>";
if (is_dir ( $gain_directory )) { //判断是目录
if ($gain_directory == ".") {
$catalog = getcwd (); //显示当前目录
$catalog = iconv ( "gb2312", "utf-8", $catalog );
echo "<a href=$php_self?catalog=".urlencode($catalog).">锁定</a>";
} elseif ($gain_directory == "..") {
$catalog = getcwd () . "\.."; //上级目录
$catalog = iconv ( "gb2312", "utf-8", $catalog );
echo "<a href=$php_self?catalog=".urlencode($catalog).">上级目录</a>";
} else {
$catalog = getcwd () . "\$gain_directory"; //子目录
$catalog = iconv ( "gb2312", "utf-8", $catalog );
echo "<a href=$php_self?catalog=".urlencode($catalog).">" . iconv ( "gb2312", "utf-8", $gain_directory ) . "</a>";
}
} else {
$ext = substr ( $gain_directory, strrpos ( $gain_directory, "." ) );
if (strtoupper ( $ext ) == ".TXT" ) {
$catalog = getcwd ();
$catalog = iconv ( "gb2312", "utf-8", $catalog );
echo "<a href=./look_file.php?catalog=".urlencode($catalog)."&filename=" . urlencode(iconv ( "gb2312", "utf-8", $gain_directory )) . "&type=" . urlencode($ext) . ">" . iconv ( "gb2312", "utf-8", $gain_directory ) . "</a>";
} else {
echo iconv ( "gb2312", "utf-8", $gain_directory );
}
}
if (is_dir ( $gain_directory ))
$file_size = "目录";
else
$file_size = filesize ( $gain_directory );
echo "<td>$file_size</td>";
$create_time = date ( "Y-m-d H:i:s", filectime ( $gain_directory ) );
echo "<td>" . iconv ( "gb2312", "utf-8", $create_time ) . "</td>";
$update_time = date ( "Y-m-d H:i:s", filemtime ( $gain_directory ) );
echo "<td>$update_time</td>";
echo "<td>";
if ($gain_directory == ".") {
$catalog = getcwd (); //显示当前目录
} elseif ($gain_directory == "..") {
$catalog = getcwd () . "\.."; //上级目录
} else {
$catalog = getcwd () . "\$gain_directory"; //子目录
$ext = substr ( $gain_directory, strrpos ( $gain_directory, "." ) );
if (strtoupper ( $ext ) == ".TXT") {
echo "<a href='delete.php?catalog=".urlencode($catalog)."&filename=" . urlencode(getcwd ()) . "' title='删除目录或者文件' >删除</a>";
} else {
//echo iconv ( "gb2312", "utf-8", $gain_directory );
}
}
echo "</td>";
echo "</tr>";
}
closedir ( $ml );
?>
</table>
第2步，创建look_file.php文件，完成对.txt’后缀文件的读取操作。
<a href="index.php">返回目录</a> <br>
<?php
$catalog = iconv ( "utf-8", "gb2312", urldecode ( $_GET ['catalog'] ) ); //获取文件的信息,设置编码
$filename = iconv ( "utf-8", "gb2312", urldecode ( $_GET ['filename'] ) ); //获取文件的信息,设置编码
$type = iconv ( "utf-8", "gb2312", urldecode ( $_GET ['type'] ) ); //获取文件的信息,设置编码
$arr = file ( $catalog . "\\" . $filename ); //读取文件
foreach ( $arr as $value ) { //循环输出文件内容
$value = htmlentities ( $value, ENT_COMPAT, "UTF-8" ); //特殊字符的转换
echo $value . "<br>"; //输出内容
}
?>
第3步，创建delete.php文件，完成对指定文件的删除操作。
<?php
header("Content-type: text/html; charset=utf-8"); //设置文件编码格式
$count=substr_count($_GET['catalog'],'.');
if($count>=1){
if(unlink($_GET['catalog'])){
echo "<script>alert('文件删除成功！'); window.location.href='index.php?catalog=".urlencode($_GET['filename'])."';</script>";
}else{
echo "<script>alert('文件删除失败！'); history.back();</script>";
}
}
?>
一个好的功能模块，不应只在一个程序中使用，还应具有重用价值。例如，数据库的连接、操作方法以及分页技术等，一次开发后将会在很多的程序中使用，避免对类似程序进行重复开发，浪费不必要的时间。作为一个程序员，在每次开发时不仅要考虑新的功能、新的技术，更重要的是充分运用已有资源，既可以提高程序的开发效率，又可以避免开发新技术产生的一些问题。