尝试使用此方法:

$dir      = opendir($path);
$filename = array();

while ($filename = readdir($dir)) {
if (eregi("\.pdf",$filename)){
    $content  = shell_exec('C:/AppServ/www/pdfs/pdftotext '.$filename.' ');
    $read     = strtok ($filename,".");
    $testfile = "$read.txt";
    $file     = fopen($testfile,"r");
    if (filesize($testfile)==0){} 
    else{
        $text = fread($file,filesize($testfile));
        fclose($file);
        echo "</br>"; echo "</br>";
    }
}