app2/comment.php

<?php
   require_once "pdo.php";
   session_start();

if(isset($_POST['comment'])&&isset($_POST['id'])&&isset($_POST['article_id']))
{
    if (strlen($_POST['comment']) < 1 ) {
    $_SESSION['error'] = '输入不能为空';
    header( 'Location: view.php?article_id='.$_POST['article_id']) ;
    return;
}

$sql = "INSERT INTO commentsss (comment_id,article_id,name,user_id,content) 
          VALUES (:comment_id,:article_id,:name,:user_id,:comment)";
$stmt = $pdo->prepare($sql);
try{
    $stmt->execute(array(
        ':comment_id' => $_POST['id'],
        ':article_id' => $_POST['article_id'],
        ':name' => $_SESSION['name'],
        ':user_id' => $_SESSION['user_id'],
        ':comment' => $_POST['comment']
    ));
    }catch (Exception $e) {
        $_SESSION['error'] = '非法';
        header( 'Location:view.php?article_id='.$_POST['article_id'] ) ;
        return;
    }

$_SESSION['success'] = 'Record Added';
header( 'Location: view.php?article_id='.$_POST['article_id']) ;
return;
}