Drupal 8 Custom module example

example.info.yml

name: Drupal 8 custom module example
type: module
description: 'Example for Drupal 8 modules.'
package: Custom
version: 8.x
core: 8.x

example.module

<?php
/**
 * @File
 * Example custom module for Drupal 8.
 * @author Rakesh James
 */

/**
 * Implementing hook_menu().
 */
function example_menu() {
  // The paths given here need to match the ones in example.routing.yml exactly.
  $items['/mypage/page'] = array(
    'title' => 'First page',
    'description' => 'This is a example page.',
    // The name of the route from example.routing.yml
    'route' => 'example.my_page',
  );
  return $items;
}

example.routing.yml

example.my_page:
  path: '/mypage/page'
  defaults:
    _content: '\Drupal\example\Controller\ExampleController::myPage'
    _title: 'My first page in Drupal8'
  requirements:
    _permission: 'access content'

ExampleController.php

<?php
/**
 * @file
 * @author Rakesh James
 * Contains \Drupal\example\Controller\ExampleController.
 * Please place this file under your example(module_root_folder)/src/Controller/
 */
namespace Drupal\example\Controller;
/**
 * Provides route responses for the Example module.
 */
class ExampleController {
  /**
   * Returns a simple page.
   *
   * @return array
   *   A simple renderable array.
   */
  public function myPage() {
    $element = array(
      '#markup' => 'Hello world!',
    );
    return $element;
  }
}
?>