Custom Post Type Not Working

I am making a new theme and need a custom post type for “Books”. I used this website to generate the custom post type code for the functions.php file.

While the list of “Books” works fine, for some reason I keep getting a 404 error for the single “Books” page. I followed the instructions on the WordPress Codex site in terms of naming the file (single-mj_books.php) but it still isn’t working.

Here is my functions.php code:

class mj_books {

	function mj_books() {
		add_action('init',array($this,'create_post_type'));
	}

	function create_post_type() {
		$labels = array(
		    'name' => 'Books',
		    'singular_name' => 'Book',
		    'add_new' => 'Add New',
		    'all_items' => 'All Books',
		    'add_new_item' => 'Add New Book',
		    'edit_item' => 'Edit Book',
		    'new_item' => 'New Book',
		    'view_item' => 'View Book',
		    'search_items' => 'Search Books',
		    'not_found' =>  'No Books found',
		    'not_found_in_trash' => 'No Books found in trash',
		    'parent_item_colon' => 'Parent Books:',
		    'menu_name' => 'Books'
		);
		$args = array(
			'labels' => $labels,
			'description' => "",
			'public' => true,
			'exclude_from_search' => true,
			'publicly_queryable' => true,
			'show_ui' => true,
			'show_in_nav_menus' => true,
			'show_in_menu' => true,
			'show_in_admin_bar' => true,
			'menu_position' => 20,
			'menu_icon' => null,
			'capability_type' => 'post',
			'hierarchical' => true,
			'supports' => array('title','editor','thumbnail'),
			'has_archive' => false,
			'rewrite' => array('slug' => 'books'),
			'query_var' => true,
			'can_export' => true
		);
		register_post_type('mj_books',$args);
	}
}

$mj_books = new mj_books();

Is there something I am doing wrong? Please help. Thanks!