<?php
class PostsController extends AppController {

    public $helpers = array('Html', 'Form');

    public function index() {
        $this->set('posts', $this->Post->find('all'));
    }

    // 追加 Start ------------------------------------------------
    public function view($id = null) {
        if (!$id) {
            throw new NotFoundException(__('Invalid post'));
        }

        $post = $this->Post->findById($id);
        if (!$post) {
            throw new NotFoundException(__('Invalid post'));
        }
        $this->set('post', $post);
    }
    // 追加 END --------------------------------------------------
}

<!-- File: /app/View/Posts/view.ctp -->

<h1><?php echo h($post['Post']['title']); ?></h1>

<p><small>Created: <?php echo $post['Post']['created']; ?></small></p>

<p><?php echo h($post['Post']['body']); ?></p>